After a brief look both here and viewing other's modifications on CZcams,, I don't see any suggestion to use silicone HEAT SINK GREASE when mounting the bridge rectifier. That is always a good thing to use for transferring heat away from the rectifier unit. It is low-cost enough to be included in the budget mod..
I do mention that for anyone doing this they would be best to have a dedicated heat-sink for the rectifier. But you are correct; the use of a thermal interface material between the rectifier and heat-sink would definitely be advised. I never intended this video to be a full tutorial, so I didn't get into those types of details. But that's something that shouldn't be overlooked. Thanks.
Spent many years in the electronics industry, whenever attaching a heatsink, ALWAYS use thermal grease. A poor thermal connection between a component and the heatsink can /will reduce the effectiveness of the H.S. by 50% or more. Just a dab will do. You’re only trying to fill the pores/gaps between the two surfaces. Too much actually increases the thermal resistance.
Thermal grease is to be used on mirror like finishes and in minuscule amounts. When you cake it on there and let it squeeze out the sides it is making more of an insulator than a thermal transfer paste.
Thank you. Just installed a $21 200amp bridge rectifier in a HF 125 flux core welder without a capacitor based on your youtube video. I am extremely happy with the results without buying the additional parts. I could not justify the added expense, I would just buy a better welder. Being a novice welder I had terrible welds with the original unmodified configuration, now I see much better penetration.
This is a helpful comment. I'm about to convert my 90 amp and don't want to throw more than $30 at it. I'm stoked about getting better welds with less wire and less grinding.
you showed me more useful info in less time by actually getting to the point and with shots of before and after welds than any boring multipart series so far.. i"ve decided to go with capacitors and a greased heat sink. results will have to be at least equal to what you have shown . also a replacement shrouded fan from a computer. thank you
@@steven33068 Directly from a PC they are typically 12VDC. There are many fans that are the same size that are 120VAC also. Just searched Amazon and found several.
Thank you for doing the conversion and showing us the results! Definitely an eye opener comparing the penetration results between the stock AC and the DC- with only a rectifier! Would be interesting to see the results with adding the capacitor you mentioned perhaps doing to yours. I know you explained how you spliced in for adding the rectifier, but (for me anyway) I’m not sure I understand HOW you spliced in or with what wire I could purchase. You did show us where the connections come from internally and go to on the rectifier. I can solder and put heat syncs on, I just didn’t understand the location to cut and type wire to use. Thank You Very Much for doing the conversion, showing us the component to do it cheaply and those amazing results!
For cable, I used 4 gauge welding cable (purchased on Amazon). You could use just about any 4 gauge wire, but "welding" cable has more, smaller strands so it is more flexible and easier to work with. The wire that comes from the transformer is a stiff, solid wire. It is spliced to a more flexible wire that runs to the work clamp on one side, and that runs to the wire feed system on the other side. At each of these splices there is a small, white wire that is also spliced on. This white wire must stay on the AC side. That is all how it is from the factory. I simply cut the flexible cables after the splice. Once you cut both (one for the work clamp, one for the wire feed) you have four ends; two which lead to the transformer, one that leads to the work/ground clamp, and one that leads to the wire feed system. The 4 gauge wire I purchased was simply used to extend each of these to reach the rectifier. Hopefully that makes sense. Let me know if you need clarification on anything.
Thanks to this video, I modified my "Speedway" 90A flux welder by wiring in a 200A rectifier. Immediately I noticed almost no spatter and my welds were consistent, flatter, and immeasurably better than what I was getting from the AC output.
Nice. Glad it worked out for you. One thing I didn't really cover in the video is that a heat sink and thermal interface material (paste or pad) would be a good idea for the rectifier. I didn't use one for the video, but for long-term use, the rectifier will hold up far better if you are able to draw heat out of it.
@@bigtb1717 Thank you for posting this and mentioning the heat sink. I plan on making my own to fit the small confines of the welder's case. I had to move the main transformer fully aft and mount the cooling fan outside the case just to fit the rectifier. :)
I just did this conversion with just the 200 amp full bridge rectifier omg 😱 day and night difference, almost no more bb spatter, and I noticed a huge power increase, soo much hotter and soo much more penetration with .035 flux core maxed out wow 🤩, so with 30 bucks for 200 amp rectifier holy moly soo much smoother arc and like 90 percent less spatter totally worth it and this video confirms it
i absolutely loved this video, thanks man. i love messing around with welders. i modded a clarke mig 150en with a spool gun, and modded a cheap Chinese arc welder to run scratch tig with foot pedal to control amperage,just for fun, both working great.
Start collecting transformers out of microwave ovens (MOTs). Tear out the secondary coils (real thin wires) and replace them with about 14 or 15 turns of 8AWG. Hook up four good sized ones in parallel if you want to run it 120V. Or connect 2 in series and the other 2 in series, then both of them in parallel if you want it 220. (These connections are for the primary coils only. Keep all the secondary coils in parallel.) To give you an idea on how it works... Microwave ovens need about 2200 volts to work, not alot of current. Arc welders are the oppisite. They need more current and less voltage. So the primary coil in both the ovens and welders stay the same, but the secondary are different. Many turns of a thin wire in the secondary produces hi voltage, but low current. Thicker wires at less turns produces more current and less voltage. Each transformer should be as close to each other in size, but not really crucial if youre connecting them all parallel at the primary for 120V use. Just make sure all 4 secondaries have the same guage wire and same amount of turns and are all connected in parallel at the secondaries. This keeps the voltage low but increases the current. You probably already know all this stuff...I sorry. Lol Lota videos on this though in the case you dont.
Ok so I did mine and the only issue I had was I didn’t plant out the mounting of the rectifier correctly so that when reassembled, one of the screws that hold the pos. Lead on the rectifier was hitting the big metal part (transformer?) in the welder and shorting it out and blowing a circuit when 8 pulled the trigger. So I had to find a couple pan head screws to use and it gave me the clearance I needed so it wouldn’t short itself out. Did a few test welds and what a difference this hack makes. A lot less spatter, and stronger welds plus... when I used to run it as stock, A/C, if I tried to run a bead more than 4 inches or so long, it would pop the 20 amp circuit in my garage... now I can run them all I want with no problems. The only thing I did notice, don’t know if it’s good or bad was that I used to be able to run it on “high” with a wire speed of 7 but now, it sputters on 7 but works great on 4 ...go figure. But I am happy with the turn out... it’s a lot better welder now.
this is some great info I have the harbor freight flux welder and its absolute shit I will be doing this but ill use a dedicated heat sink thanks for the info what size was those terminals you used
the biggest problem with doing the conversion the way it's done here because of exactly what he pointed out, the current for the wire feed circuit is pulled right from the transformer with the current for the gun and because the connectivity and penetration is so much better after conversion so much more current goes out to the weld that it ends up starving the wire feed circuit burning out the pcb, the only successful HF conversions that actually last are the ones where they also added a separate transformer to run the wire feed and increased the cooling and lastly a large heat sink for the rectifier is a must, big cap also helps smooth out the current. do the conversion right and the HF welder will out weld any of the lincoln 115v welders...
I got the Jobsmart 125 MIG from Tractor Supply. About 10 years ago. Similar transformer type, AC output flux core by appearance. However mine does use a seperate transformer for the wire feed. My wire spool loads from the side. I had plenty of room to bolt the 200amp bridge onto an amazon heat sink about 4x6 inches thats near an inch thick. Bought a metric tap and used the machine screws that come with the rectifier. And some thermal paste. Mounted the bridge/heat sink near the fan with lots of room for airflow. F.Y.I. Stated output on the front of the Welder cabinet says: "27.1vac @80 amp high." "17.1vac @40 amp low". Adding the rectifier you, subtract 1.4 vdc across the forward diode pairs from stated voltage. And a 140 watt drop in power on high. So, it's still a weakling voltage machine. Volts should be 50 vdc open circuit. Next time buy a Inverter type for 3 X. more $.
I have this exate machine and rectifier and your video is the only one I've been able to fine of this exact model. can you show me or explain how the min max switch and power switch is wired? I made the mistake of unplugging everything during a conversion and don't know how to reconnect everything. I'm pretty close to having it hooked back up properly but I can't get the Wire feed to ingage and I keep blowing the breaker.
Great video. I'm planning on converting my harbor freight welder next week. I have just 2 quick questions about the welder. First, where do you connect the white wire for the wire feed and second, how has the welder been working for you because I see other videos where they are using transformers and other crap which is to me over kill. I like your way because you just use the rectifier only. Again, great video and thanks. Your boy Eric from So.Cal.
I just left that wire where it was. Just make sure that if you do cut or disconnect that wire that you re-connect it on the AC side of the circuit. I simply connected the rectifier after that wire and all was well. I honestly haven't used the welder much. There shouldn't be an issue not using a capacitor or inductor. Using them just smooths out the arc. But the way I did it was just for proof of concept and testing, not for long term use. If you want it to be reliable you should install a heatsink on the rectifier and use some type of thermal compound between the rectifier and heatsink for proper heat transfer.
Just watched this video. You can use a thick piece of square or rectangle aluminum dimond plating for a heat sink from menards or Lowe's . Just put the dimond side facing towards the metal plate your going to mount the electrical box to then between the aluminum plate and that electrical box you installed put some heat sink compound between the two to help wick away the heat. The gaps between the diamonds act as passage ways for the air to flow through to help wick away the heat . On my harbor freight mig welder i changed out the ground clamp to a better quality clamp with a stronger bit and oiled the rotating shafts and bearings . I also buy rolls of mig wire from menards since its made in america and if you buy 3 or more it drops the price from 17.00 something 16.00 something a spool. I buy the small spools . Menards is cheaper on rolls of wire compared to harbor freight or other places. I also use a heavy gauge extension cord when welding. When your weld plates like you did your suppost to angle grind the edges of the plates : V shape to make a better stronger joint/seam weld.
Are you saying I should have bevel the edge of the vertical piece on these joints? If you are trying to get a full penetration weld, such as on a butt weld, then beveling can help and may be required. But with a fillet weld on a "T" joint or an inside corner joint in general, beveling isn't always practical, and it isn't normally done as far as I know. There may be situations where it is done, but I don't think it's typical. With an inside corner joint the fillet size determines the strength of the weld, and many weld specifications will call out the weld height and leg size for the fillet on an inside corner joint. With something like a thick pad-eye or similar situation, a bevel could be worthwhile. But with a typical inside corner joint like I show in this testing, I haven't seen beveling done. But if I'm missing something, let me know. I'm always willing to learn, and if there is a common procedure of beveling inside corner joints that I've missed, I'm all ears. Thanks.
Sorry, but your logic in using diamond plate as a heat sink, is flawed. What you want is maximum surface contact between the rectifier body and the surface it's mounted to. The air gaps caused by the diamonds on the plate material won't "wick away" the heat, as air is a poor conductor of heat compared to metal. You are correct with regard to heat sink compound.
Thank you so very much. I have the 90 amp model and it is pretty much useless at anything more that sheet metal. Have you considered adding Dinse plugs to allow a conversion to stick welding also? 3/16" rods would be well within your 125 amp range and you could weld DC+ or DC- and use almost any rods out there...
I cut the wires with a small wire/cable cutter I have. It's just a little hand-held snips made for wires. You could also just use a pair of side-cutters. I soldered the wires together and protected the connections with shrink tube. The ring terminals I crimped on, then soldered.
Great video and demo! What's your thoughts on doing this modification for spot/butt welding thin gauge sheet metal? I'm restoring a 16 Gauge exhaust system and want to reduce the chance of burning through. Would this assist or should I just keep practicing on scrap pieces (16-18 Gauge)?
After the conversion it will weld much smoother, but I don't think it will prevent burn-through on thin material very much. It might help a little, just due to the more consistent arc, but I think practice and figuring out a technique that works for you will be more important. The limited setting adjustments on this welder are what is going to hold back its performance on thin material more than anything. What size wire are you using? If you are are using 0.035" wire by chance, moving down to 0.030" wire might help a tiny bit as well.
@@bigtb1717 Nice, thanks for the soliid info. I was using the genertic 0.30 but got some brand name 0.30 recentley. Notice the feed roller was set for the 0.35 initially from the store. Was just practicing on 16G. Getting better!
I was excited to see the posting of this video. Seeing those results I personally think that the conversion is worth the effort even if it's only installing the rectifier. What wire were you using in this test? Is the welder on a 20amp circuit? Last question, is this machine the newer 125 or the older 90 machine? Thank you for posting your test and results.
It is the newer 125A machine. I do have it plugged into a dedicated 20A circuit on a 20A breaker. Edit: Also, in previous testing I measured 130-140 amps of output from this welder when plugged into the same outlet, so I don't think the supply is holding it back any more than any other 120V circuit would hold back any welder. If someone already has this welder and can't afford something better, I agree that it's a worthwhile modification. In fact, if it were my only welder I'd probably get a capacitor for it as well. Should smooth out the arc. If someone is just starting out, it might be worthwhile to look into other options, vs. buying this one with the intention of modifying it. We're spoiled for choice these days.
Oh, and I was using Lincoln NR-211MP wire. Common stuff, picked up at the local big box hardware. I like that wire a lot better than the stuff that came with the welder.
bigtb1717 I have the 90amp version but haven’t used it YET - haha. You mentioned “other options” if purchasing new. What DC flux core welder would you suggest for someone like me who is budget restricted?
Keep in mind, none of the other options are nearly as cheap as the HF welder. I will be reviewing the Century FC90 soon. It used to be $169, but it is $199 now, as far as I can tell. It is a DC output welder and I'm optimistic about performance, though I have barely used it so far. Lincoln has a DC output flux core for around $270. Quite a step up in price, but it works well and is simple and reliable. I haven't looked into other options much, but I'd look into Everlast, Razorweld, Klutch and possibly a few others I can't think of off-hand. You may end up still deciding the HF fits your budget best. It is definitely the cheapest.
I see your rectifier is rated at 200 amp, 1600v. Amazon has several flavors of that are there any other specifics I should know before ordering? Thanks for this video.
I picked the one I did based on amps (200A gives a bit of breathing room, for hopefully better reliability), it had screw terminals, and it was prime shipping from Amazon. You are only dealing with voltages under 50V, so 1600V is way overkill, but it's probably overrated anyway. You just need a single phase, full-wave (most you'll find are full-wave, but just make sure you don't get a half-wave) bridge rectifier that can handle the amps and volts. Nothing else special about it. There is a 150A rectifier on Amazon for under $14 shipped that is smaller and would be a bit easier to fit inside. It is from the same seller I ordered from, and I would have tried that one first, but I decided to go up in amps. FYI, I used 4 gauge wire. I didn't do this yet, but I may end up putting a thermal pad between the rectifier and the side cover of the welder. Neither surface (the back of the rectifier or the welder panel) is very flat, and a thermal pad would improve contact and may aid in heat transfer. Something you may want to consider as well, depending on where/how you are going to mount the rectifier. Good luck and be careful. Safety first when dealing with electrical components.
is 'tied in' a welding technical term? I googled it & didn't find anything similar to what you're explaining. I'm assuming you're referring to the amount of penetration, but I'm not sure. Can you please clarify? thanks
Sorry, I don't know where I picked that term up over the years. But you pretty much have it. "Tied in" just means that the the weld metal melted into and mixed with the base metal, at least slightly. It's basically just a way of saying there was at least some, small amount of penetration. So if the toes are "tied in," then the base metal melted at least a tiny bit at the toes and the weld metal and base metal mixed together a bit. So the two are "tied" together. If something wasn't "tied in," then the weld metal is essentially just laying on the base metal and the base metal didn't melt at all. The two may still be stuck together somewhat (similar to a braze or solder joint), but it isn't as strong of a connection as if the base metal had melted and mixed in with the weld metal, essentially becoming one.
I did not add a fan. That is the stock fan. I didn't inspect the fan closely. But it may be a universal, brushed motor, or it could be an AC motor fan.
Just FYI, I ordered an Amico ARC140 and should have it in a week or two. Once I have it and get time, I'll be testing it out and making a video or two about it.
Yes, that is how I had it set up. Flux cure runs really poor on electrode positive (negative "ground"). Converting to DC and running electrode negative (positive ground) runs far better. AC flips polarity 60 times a second, which is one reason it runs poorly with flux core. 50% of the time it is electrode positive. Electrode negative runs smoother, less spatter and better penetration.
what are your thoughts on using 8 awg for the wiring to/from the rectifier & cap? I'm trying to get this conversion done, but accidentally purchased 8AWG THHN wire instead of going with 4 or 6 awg. Considering the short runs, should 8 AWG be ok, or will I necessarily need to go bigger?
With the short runs they would probably work okay. 8 AWG will technically have well over twice the voltage drop, compared to 4 AWG. But it's probably not enough to meaningfully effect how the welder runs. The main factor is that 8 gauge wire will heat up much faster. It still may not be be an issue for smaller projects. If you have a big project and weld a lot, you may overheat the wire insulation. It would depend on a lot of factors, like how long the wires actually end up, if they have any airflow from the fan over them, etc.
Great video. Please consider a short tutorial on the butt and ring connectors you used, how you crimped them and links to purchase them. I'm thinking of replacing my cheap Chinese ground cable with a 6 gauge cable. HF has 16 ft, 6 gauge jumper cables for $15. Do you think replacing the ground cable would help? Cheers
Replacing the ground cable probably wouldn't help much. Also, the stock ground cable is 4 gauge, so 6 gauge would be smaller and would be a down-grade.
@Dominique Hardie Awesome! Thank you so much for the info and I'll look that up now. The cable that came with my welder is only 8 gauge. I purchased a nice clamp from HF, got a 24V transformer for the wire feed motor, a 150amp full bridged rectifier and a dines connector for the ground. Cheers brother
@10:45 My Chicago Electric 125 welder from Harbor Freight came with instructions that said it was a 20% duty cycle machine out of the box. This counter renders it for spot welds or what you do a "long-run" you can go ahead and take a coffee break for 5 minutes. Not for the one making a living as a welder.
I never tried welding really thin metal with it. You can still turn down the output after doing this, but it doesn't have infinite adjustment of the voltage, so I can't say how thin of metal you could weld before or after this modification. The modification will allow it to weld smoother with far less spatter, which I think would be a good think for auto body work, but you certainly don't need extra penetration. If that is your main use case, I probably wouldn't bother with the modification.
@@bigtb1717 wouldn’t say that would be my main use case I want to be able to do a lot of things with it but auto body is definitely one of them maybe I’ll just put the Lincoln wire in it and upgrade the ground clamp and get some anti spatter spray
Great video, but for about $70 more wouldn't it make more sense just to get the Century FC-90?, and have to mess with buying all these additional parts to upgrade the HF model?
I can’t remember if I said it in this video, or one of my others on this welder, but my feelings are that if you already have this welder and want to convert it or just thnk it sounds like a fun project, by all means. But I wouldn’t recommend buying this welder with the intention of converting it to DC. Personally I’d recommend just buying a more expensive welder.
The century is an inverter. One component goes gad then you need a new welder; this one however can be turned into dc with a rectifier bridge, a transformer is way more reliable than inverter
Hey brother... which gauge wire did you use? I did this conversion a couple years ago but forgot wire size... The wire I purchased on eBay was not oxygen free and it oxidized at the terminal connectors and the unit has failed😢
One question. I have see other tutorials and they use capacitors to smooth out the current the machine puts out. Is it absolutely necessary or can I just go without it?
I didn't really intend this to be a tutorial, just a basic as possible conversion to test performance. If you are converting one for normal use the main thing you should do different than me is that the rectifier should have a heat-sink and some thermal compound between the rectifier and the heatsink. It will need something to keep it from overheating. A capacitor isn't absolutely critical, but it will smooth out the voltage and make the arc a bit smoother, so it is a good idea. It's also a good idea to have a bleed-down resistor across the capacitor so it will drain down the voltage when you stop welding. Otherwise the wire could stay live from the charge in the capacitor when you stop welding. You could leave out the capacitor and get by. Even without the capacitor it will still weld better than it does out of the box. Some people also use or create a simple inductor to smooth out the amperage as well. Again, not critical, but it may make things run a little smoother.
Thats the point of the video as far as i can tell, he wanted to show that no, smoothing caps arent 'necessary" for changing output using a full wave or bridge rectifier, its just not clean output but any kind of dc will be much better than what the hf spatterwelder can do
You could. I think the more important thing would be to put a heat-sink on the rectifier. I didn't put one on mine for the video because I mostly wanted to see how well it would run. Barring any quality or overrating issues with the rectifier, I think a single one should hold up okay if it has a heat-sink.
Putting diodes in parallel is not a good idea. It's almost impossible to get the current to divide between them equally. You'd be much better off using a 250 or 300 Amp rectifier.
Can you post a link on where to buy or just an overall search criteria for me to use I'm new to welding for the most part and am not able to make this welder perform very well stock.
Are you looking for the rectifier? You could search Amazon, eBay, etc. for 200a full wave rectifier, or 200a bridge rectifier. I hesitate to post a link because things change so often with these types of listings, it may break or simply take people to the wrong place at some point.
Yes it's the cheapest but you all will want to do a heat sink, compasidor, bleed resistor and a ferrite core and if you have the older welders you will want to put a plastic shroud around fan blades to pull air in thru back vents
For sure. Flux core will always have spatter, but AC output will increase spatter noticeably. Converting to DC will provide smaller spatter BBs that don't stick quite as hard.
I am so sorry for bothering you, but I had done everything you did to specs. Everything was fine up until the point where I turned on the welder and pulled the welding gun switch...nothing! I tried it again...nothing. I removed the motor from the welder to see how f it was bad, turns out it was still good. So whatever I did it's not getting any power to the motor. The relay is good ,the 2 fuses inside are good and not blown and there's nothing I can see physically that is wrong. What did I do wrong?
It's hard to say for sure what is wrong. The two control wires on the output of the transformer, did they both stay connected where the were? Do you have a multi-meter? If so, do you get any voltage on the wire when you pull the switch and the motor just doesn't run, or does the welding output not turn on either?
so i have the 120v 90 amp version of this...just to make sure, if i do this mod, it will then be DCEN when done? someone said it already is DCEN, that ALL Flux core welders are, Migs are not. is this true? i have a bunch of flux core wire that says you need to use DCEN thats why i ask. thanks!
After the mod it will be DCEN. You do have to ensure this when you do the mod. The rectifier will have a positive and a negative output terminal. You have connect the negative terminal to the wire feed system and the positive terminal to the work/ground clamp. There are definitely flux core welders that are not DCEN. The 90A welder you have is AC. Most self-shielded flux core wire is designed to work with DCEN, so it doesn't work very well on AC. That is why this conversion helps so much, because stock it is not DCEN, it is AC. Converting it to DCEN helps a lot. Solid wire, gas shielded MIG is normally run on DCEP for steel and stainless, DCEN for aluminum. Most MIG welders can be switched between EN and EP for running different wire, including flux core. There are even some flux core wires designed to be used with shielding gas and they use DCEP. So there are a lot of different situations. Most commonly, flux core is run on DCEN and MIG run is DCEP.
It seems that any knowledgeable welder suggest switching the DC polarity on a flux core welder, why aren't they just built this way? Or included with a switch?
This particular welder has AC output to save cost. In this video I convert it to DC output and wire it for electrode negative, which is the polarity that works best with most self-shielded flux core wire. Most flux core only welders that have DC output are built to have the proper polarity for flux core and do not need to be switched. Solid wire, gas shielded MIG uses electrode positive and most MIG welders that can run gas shielding will be built with a way to swap polarity so you can run MIG or flux core.
@@bigtb1717 I need some 8 gauge wire and connectors but also I think I'm gonna go all the way and do a cap and resistor, except im an idiote and im unsure of what to go with there too. Im fould a cap that is 47000 uf 50v and I think I can run two 10v 100 resistor. I have them in my cart but haven't purchased them yet. What are your thoughts?
So I got the wire and stuff but couldn't wait to finish my bike. All I did was change the ground clamp and that was huge. My welds are really good. My fabrication skills... not so good.look like I bought Harley parts from China.hahs but with some tweaks I managed to make them work.
Help.... lol I’m a little confused about the white wires... you said to do the splices AFTER the white wires, then you said What ever you do, makes sure they wind up on the A/C side of the rectifier. So in other words, they don’t change at all? They come out of the transformer and go to where ever... and that’s how they stay? We don’t need to switch them around like we are the big wires ? Just want to be sure. Thanks!
Correct. They can stay right were they are. By "AC side of the rectifier" I meant that they should stay on the AC side of the circuit, not that they should necessarily be connected directly to the rectifier. You just don't want them to be on the DC side of the circuit. Hopefully that makes sense.
And now, I finally got my rectifier in from amazon and I looked at it and there are no markings to tell me which side is ac and hitch is dc lol there’s just + and - but one side does have a little ~ next to each terminal...
One comment one question: First, the question - how much splatter reduction did you see with this mod? I’m planning on doing this and reducing the splatter is of primary importance to me as I have a Hobart stick welder that I use for anything structural or that needs deep penetration. I’m planning on forgoing the capacitors as well because I don’t want to put the money into it AND IMHO, it’s dangerous if you don’t do it right! I think anyone who throws a capacitor in there without a system to diffuse the leftover charge is playing with fire. Eventually, you’ll forget and grab the ground while your still holding the electrode. Second, the comment. I see a lot of people out there complaining about these welders being useless. That has not been my experience and it makes me wonder if it’s the welder and not the machine. First off, get yourself some decent wire. I use Lincoln electric flux core in .030 and .035 and it works great. Less splatter and good beads. Second, clean the surface!!! This isn’t stick welding on 220 where you’re going to punch through grease, rust and even paint without issues. Third, and I think this is likely the problem with most people - learn how to run a good bead first, preferably with a stick welder. I use my flux 125 on all sorts of materials and it works pretty good as is, out of the box (minus the splatter) especially since I got it for a $40 open box special. Turn down your wire feed to 5 or 6. Take your time and let the heat build so you create a good puddle. Stitch it back and forth. Make sure your tension is set correctly - i.e. you should be able to stop the wire with light pressure from one finger. I welded a engine cart together last week using this welder and some square stock and it’s holding my 800 lb Jeep 4.0 engine right now, solid as a rock.
Spatter is definitely reduced. Mostly the spatter is a bit more fine (smaller spatter bb size). The AC output results in larger spatter that is often more difficult to remove. With DC output it's definitely better. There is still spatter though. But there is less. I agree that if you install a capacitor it should have a bleed-down resistor to drain off the voltage. However, I would say getting flashed is probably the bigger danger as compared to shock. The open circuit voltage on a welder like this is far lower than on a stick welder, and a stick welder output is live all the time. Still could get shocked, but I think it's far more likely to simply get flashed after lifting the helmet or before lowering it if the wire touches the table or work piece. I agree that this welder is very capable for the money. Up to 1/8th of an inch thick material it works very well. Above that it gets very little penetration. Technique and settings can help achieve a decent looking weld, but I have found the penetration to be seriously lacking on 3/16" thick material. The A/C output really holds it back. With DC output it runs smoother and burns in better. But again, that doesn't mean it can't make welds that are strong enough for a lot of projects as it is out of the box. I think people go a little overboard in both directions when talking about this welder. Some people seem to adamantly claim that it is just as capable as any more expensive welder but people just want to justify their expensive welders so they put this one down. Others simply insist it's 100% junk. The truth is definitely somewhere in the middle. The machine definitely has limitations and it simply isn't as capable as a 240V welder, or even a similar welder with DC output. But within its limitations it works fine.
bigtb1717 good to know about the shock vs flash. Now that you mention it, both of my comments relate directly to another instructional video I watched today in that 1) the person who made the video flashed himself the first time he used the welder and 2) he judged the upgrade as poor because both the “beads” he put down looked like garbage - though I have seen a lot of comments knocking this welder as well. The gentleman in this other video literally just pushed the trigger and dragged the electrode for a couple seconds on the metal surface. Zero technique, zero patience. I have also found that this welder works great for the 1/16 and 1/8 tube I usually use to fab little things around my shop. If anything, I find the conservative nature of this welder beneficial in that I’m not blowing holes through square tubing left and right. Like you said, the bottom line is that this welder functions well for what it is, but is limited in versatility and will NOT weld things for you or lay perfect beads without some effort and knowledge! It’s been very handy for me around my shop though - it’s my go-to for quick tack welds with the shelves I just built, as well as thin tubing. I’m hoping that the conversion to DC will eliminate enough splatter to allow me to use it to weld frame stiffeners to my Jeep, but I’m keeping my expectations tempered. I guess that since I bought mine for a song, I tend to fall on the over-optimistic side of the argument, though! I have one suggestion/comment, and I certainly don’t want this some come off as condescending, but I’ve heard and found that, contrary to what many people assume, turning the speed down on the wire feed will allow for deeper welds. As I understand it, adding new wire/steel to the puddle has the effect of cooling the puddle, and therefore the slower you add wire, the more penetration you get (within reason). This is because: 1) the puddle reaches a higher temp because you’re not constantly adding metal and 2) the bead builds slower so you can stay in one place longer. I’ve found a wire speed of 5 to 7 to be good for most applications, with a tendency for 6. Additionally, in regarding to upgrading or adding a cooling fan - I chose to keep my secondary cooling fan on a separate circuit. Meaning I had a 115 vac muffin fan that pushes about 40 CFM laying around and decided to power it with an independent plug, the logic in this being that if the goal is to extend duty cycle, I’m better off with an independent power source rather than utilizing the welders system. This may not make much of a difference in practice, but I am a novice/hobbyist.
bigtb1717 and I absolutely agree about it not being a 240v. My Hobart stick-mate is 240 and it blows through grime, rust, and paint and still gets solid welds.
I'm always open to comments and suggestions. I understand what you are saying about heat and wire speed. In general, increasing the wire feed speed _should_ increase the amperage, causing a hotter weld. However, if the welder is near max output and you increase wire speed it could cause issues. There is definitely a point where piling too much weld on top will result in the arc basically just heating the bead, rather than burning into the base metal, but often that's from too slow a travel speed for the wire feed rate, rather than due to wire feed rate itself. I have a video where I tested this welder with different combinations of travel speed and wire feed speed settings, cutting and etching each joint and comparing penetration. Actually, I think one of the sets of etched welds I show for comparison in this video is from that testing. One way or another, I've always heard that with welding, never say never because there are exceptions to everything.
Ive heard to reduce splatter, you need to switch to electrode negative, so your hottest point is the metal you're welding into, rather than using 70% power on the tiny wire. Ive also heard that these Chinese machines (or any smaller welders, potentially) need to "warm up" before it starts to penetrate as intended and not splatter as much. I have the dinky 90amp version of the flux core welder and it takes a bit of time before it really starts to weld easier (same techniques/settings, just a warmed up machine).
Thank you for the video, I'd be interested in seeing more tests on this. I'm curious, you went DCEN correct? Because some set it like it's regular MIG not knowing the difference.
Yep, DCEN. I went over it pretty quick in the video, but I did mention connecting the positive terminal on the rectifier to the work clamp and the negative terminal connected to the wire feed. I've made the mistake of running self shielded flux core on DCEP in the past, and it runs worse than AC.
@@bigtb1717 I must have missed it, but yeah. My friend bought this machine and when I used it I immediately decided it needed to be converted, so I've been looking into there simplest way to do so and your video was very helpful.
bigtb1717 You mention you might put a capacitor in. Please tell me why, what size/type (perhaps a link to the one you would suggest) and how you would wire it in? Thank You Very Much!
I don't know how much you know about how AC power works, but the voltage is a sine-wave pattern that alternates back and forth between positive and negative. The rectifier changes the negative portion to positive, so the output is always the same polarity, rather than alternating. But since the source is a sine-wave, the output from the rectifier is constantly pulsing. A capacitor can help smooth out these pulses and in turn, smooth the output of the welder. A capacitor would get wired in parallel with the DC output. It would ideally use wire as large (or nearly as large) as the rest of the circuit. I think 50,000 uF or more is generally recommended. A capacitor stores voltage, so you would also want to connect a bleed down resistor, otherwise the output can stay live after you stop welding. Many people add an inductor as well. Leaving out these extra components is why an AC output welder can be so much less expensive. That's why I wanted to see how much difference just a rectifier made, without also having to stuff a capacitor, inductor and related items into the welder.
@@bigtb1717 thank you for that explanation. I've seen videos of the much bigger mod. So if this mod fails and I'm assuming the bridge would go first. Would I just replace it and try again?
Strange. That shouldn't have changed. Is the wire feeder running constantly as well? If I remember correctly, the power for it came from the output transformer.
@@bigtb1717yeah I wired it up again and it still is always live, idk where I went wrong. I wired up the clamp to negative, the gun to positive, and does it matter which side goes where for the ac parts bc I just did them at random?
I have a brand new 125 never used yet, not a welder so I'm getting as much advice as I can here. I cant weld until Saturday because my helmet isn't here yet. So I could the dc bridge and bought it and a bett ground clamp for 26 $ on Amazon free shipping if you buy the clamp. Hows it holding up,and have you used it much? And as a newbie should I do it?
I would try it as-is first. On thinner stuff (1/8") it will do okay stock. If you do decide to put in a rectifier, I would recommend getting a heat-sink for the rectifier. I didn't use one because I wanted to easily and quickly see how much difference a rectifier alone would provide. If I was going to be using the machine a lot, I'd want a heat-sink. On that note, I haven't use the welder much since the conversion.
@@bigtb1717 like everything else I found one on Amazon. Thanks again for all your help. My helmet should come today and I have a whole lot of scrap stuff ..so here I go.
@@davidfellows6250 Cool. The smoke from flux core builds up quick. Good ventilation is important and is easy to overlook. No matter how cold it is I open the garage door when I weld flux core. Also, fumes from anything zinc plated can make you sick, so be mindful of that when welding anything zinc plated. Also, never clean something you are going to weld with brake cleaner. The fumes from super-heated brake cleaner can be extremely poisonous. Just something some things to think about. Be safe and have fun!
I had a big project for work and then I went on vacation. I should have a few calm weekends coming up (hopefully). I plan to do some welding videos soon. It shouldn't take much time to check the DC output of this machine once I get back to it. I'll add that to the list. Thanks.
I notice I'm commenting on a video that is several months old, but I have a few questions if you can help. First one is the connection of the rectifier. On the AC side does the connections matter? Is there a positive on negative on that side? Then on the DC side you make the gun portion connect to the negative and the ground clamp connect to the positive? Also, will this still only arc when the trigger is pulled or will it be hot without trigger pulled? I've seen several videos of people saying after installing the capacitor they needed to discharge it since it was still live.
There is no polarity on the AC side. On the DC side you are correct, negative goes to the wire feed/gun and positive goes to the ground/work clamp. If you install a capacitor it will charge up as soon as you start welding and will stay charged when you stop, leaving the wire live. If you install a capacitor it is highly recommended that you install a discharge resistor across the capacitor. I'd have to do a bit of research to get recommendations for resistor ratings. The resistor will cause a bit of draw on the capacitor and will drain it down when you stop welding, so the wire doesn't remain live.
I like your ideas,,, and I have a new HF 125 welder, want to use it for thin gauge metal without all the splatter. Question: How about using a 300 amp 1600 v rectifier to decrease the amount of heat stress and a heavy duty induction/coil to smooth current out a little.? $25 on ebay
An inductor can be helpful, but how large or how small an inductor can make a difference in the arc. It's difficult to say just how large or small an inductor you would want to use. You probably wouldn't need to buy an inductor, I think some people just wind a wire around something inside. I've seen on forums where guys talk about how many turns of wire they use. I'd say a capacitor is probably just as important for smoothing things out.
@Mere Woman; Thin gauge metal? Buy an Inverter machine that can dial down current to 25Amp. Spend About $75 more than this welder. But If you try this mod, I believe you will need: A large aluminum finned heatsink, screwed to the rectifier base with a thin film of thermal paste in between. And positioned in the case for fan airflow to dissipate heat. After the mod, it's still a 20% duty cycle machine. 2 minute weld time, followed by eight minute cool down. An Inverter machine may have a 60% duty cycle.
The common self shielded flux core wires that people would run on this machine are going to run on DCEN. DCEP runs very poor with self shielded flux core and would be extremely unlikely to give satisfactory penetration. There are some gas shielded flux core wires, and some specialty self shielded flux core wires that run on DCEP, but I don't know of any that could be run with this welder.
I know this is a L O N G time after your video, but... Could I bolt a square flat piece of aluminum to the place you bolted the rectifier first, then bolt the rectifier to it as a heat sink? The aluminum dissipating the heat faster than metal. Or is that too simple minded? Oh, thanx for the help and tests on things to show real life results. Good stuff!
A plate of aluminum would definitely help a little, particularly if it was flat and could draw out heat more efficiently, but something that was exposed to the outside of the case or to the airflow of the fan inside would be better.
@@bigtb1717 Good point! Yes, it was my intention to use a flat piece of aluminum about a quarter inch thick and bigger than the base of the rectifier so it's bolted first, then the rectifier onto it. Of course, cutting a square hole in the side along with the aluminum would ensure a good cooling!
@@atran3462 Yes, this welder is poorly conceived as built. However, supply chain from China sells many, many Bridge Rectifers. Adding much extra profit.
I agree. In my video I just wanted to test the penetration difference, but if you want to do this on a machine that will get much use and want it to be reliable, you will want some kind of heat-sink on the rectifier and would ideally have a thermal interface material between the rectifier and heat-sink.
In early March 2023 I have browser-searched for DC welders with transformer arc generation. I could not find any under $600.00 U.S.D. Therefore-to put $200 in this $150 purchase price still has you at least $250 to the better and in Illinois you'll have to pay another $60 in sales taxes.
Can upgrading the power cord to the machine from the stock one help it get more power easily to the machine? My little portable Chicago ele. stick welder has a much thicker power cord on it than my 90 amp Chicago ele. flux core. I'm thinking, bigger power cord plus this mod and adding a better ground clamp would go a long way. Also, whats your thoughts on replacing the electrode gun and cable with a better one? Or don't bother as it wont make any real difference?
Upgrading the power cord probably wouldn't make a big difference, but it might help a tiny bit. It's probably not long enough to cause much voltage drop, but the less voltage drop, the better. A better ground clamp can definitely help with consistency, and is worth the upgrade, in my opinion. I don't know that replacing the gun and cable for it would be worth the effort. It's not the greatest, but I don't think it's holding the machine back very much.
someone needs to come up with a amp control. thin metel pow holes ... lower amps or voltage i guess easier on the dc side to do this.. good video tho i was goin to do this 2 years ago hahhaah have all the stuff .. still not get to it hahah
For self-shielded flux core, the "electrode" should be negative. So after the conversion the wire drive should be connected to the negative (-) output of the rectifier and the work/ground clamp should be connected to the positive output of the rectifier.
Yes, once you convert to DC, the output of the rectifier will be DC with + and - terminals. So the polarity can be set properly for flux core when you are installing the rectifier.
I do want to copy this, I know how to connect terminals and solder. The main issue with the video is that all the heat shrink, wires splices, etc, it's all black. It isn't very helpful for someone not familiar with the various parts of a transformer or welder on an electrical engineering level. Knowing my luck, I'd try to do the conversion and blow something up with the welder. The video could be improved with perhaps a voice over, a freeze frame, and some hand-drawn arrows using the before and after shots of the welder's internals. Or a diagram?
Unfortunately, this video was never really meant to be a "how-to" for this conversion, I just wanted to show, in general, what I did. This video was more about showing the drastic difference in performance after doing nothing more than rectifying the output to DC. For instance, at the very least you should also put some type of heat-sink on the rectifier with thermal paste between the two. A capacitor (or capacitors) will also help to smooth the output, though it's not strictly necessary. I could probably make a diagram or a new video if you can't find any other how-to videos out there.
@@bigtb1717 I get that. The unfortunate thing is almost every video I manage to find is about 2 or 3 years old and the presentation is from a post-project perspective. Or the quality of the video is potato grade. Searches for some higher quality video and information lead me to your video. I guess the search goes on, lol.
I actually have a second one of these welders. I’ll consider doing a full, start to finish DC conversion video with it. But it might be a while before I can get to it. I’ve been really busy with work and family stuff, so it might take a while to get around to it.
I agree. Now that the Titanium 125 is available I definitely recommend it over this machine in general, and I certainly wouldn't recommend purchasing this machine with the intention of converting it.
The Titanium is better in that it is already DCEN. However this welder will take a 10# wire spool where the Titanium will only take a 2# spool. I bought mine before knowing about the AC issue. Ignorance is bliss. I likely would have bought the Titanium, had I known the difference. I did convert mine to DCEN with a capacitor and it made a whole new welder out of it.
But it is not "putting lipstick on a pig" as the first video before yours on this DC conversion topic. If "$xx.xx" raises the value of the machine, them the machine is no longer a "X" value; it value has increased. If you put a strong running Chevy 454 big block in a canoe, the canoe is now worth more than before the addition of the big-block. In fact, it could be that an "$xx.xx" investment/modification could increase the machines value by a multiple of the cost to convert it. The video I watched before your put in a heat sink about triple the thickness of the rectifier.
I did the conversion as basic as possible just to demonstrate the difference in performance, even without anything other than a rectifier. If someone was going to do this conversion with the intention of putting it through normal use, they would definitely want to use a proper heatsink for the rectifier. In general, I wouldn't recommend anyone purchase this welder with the express purpose of converting it, unless they just wanted a project or something, in which case, have at it. But considering the cost of welders like the Titanium Flux 125, which is better in many respects, I'd definitely go that route over buying and converting this one. But if you already have this welder and want to convert it, you can definitely get more performance out of it after converting it to DC.
@@bigtb1717 Ya- The expense of $50.00 is so much better than laying out two Ben Franklin's plus 10% sales taxes for another machine with my 30-year on-and-off cash starvation situations in my life.. I rest the welder 4/5ths of most times. If I violate, then Inlet it sit for 8x the summation of time violated. I just have 12-linear-inches to perform. But I just am not getting the hang of it. I am welding 11-gauge cold steel to a hike I made subframe on a 1999 Toyota Solara to change out a bad caged nut..
After a brief look both here and viewing other's modifications on CZcams,, I don't see any suggestion to use silicone HEAT SINK GREASE when mounting the bridge rectifier. That is always a good thing to use for transferring heat away from the rectifier unit. It is low-cost enough to be included in the budget mod..
I do mention that for anyone doing this they would be best to have a dedicated heat-sink for the rectifier. But you are correct; the use of a thermal interface material between the rectifier and heat-sink would definitely be advised.
I never intended this video to be a full tutorial, so I didn't get into those types of details. But that's something that shouldn't be overlooked. Thanks.
I used the grease...and used an old heat sink from a junked PC I had in the shop...it was the same size of the rectifier !
Spent many years in the electronics industry, whenever attaching a heatsink, ALWAYS use thermal grease. A poor thermal connection between a component and the heatsink can /will reduce the effectiveness of the H.S. by 50% or more. Just a dab will do. You’re only trying to fill the pores/gaps between the two surfaces. Too much actually increases the thermal resistance.
Thermal grease is to be used on mirror like finishes and in minuscule amounts. When you cake it on there and let it squeeze out the sides it is making more of an insulator than a thermal transfer paste.
Very nice how you show the cross section cut view, great work
Thank you. Just installed a $21 200amp bridge rectifier in a HF 125 flux core welder without a capacitor based on your youtube video. I am extremely happy with the results without buying the additional parts. I could not justify the added expense, I would just buy a better welder. Being a novice welder I had terrible welds with the original unmodified configuration, now I see much better penetration.
This is a helpful comment. I'm about to convert my 90 amp and don't want to throw more than $30 at it. I'm stoked about getting better welds with less wire and less grinding.
you showed me more useful info in less time by actually getting to the point and with shots of before and after welds than any boring multipart series so far.. i"ve decided to go with capacitors and a greased heat sink. results will have to be at least equal to what you have shown . also a replacement shrouded fan from a computer.
thank you
How did you add a shrouded pc fan from a pc when they are DC fans? The output to the stock fan is AC. Im trying to do the exact same thing.
@@steven33068 Directly from a PC they are typically 12VDC. There are many fans that are the same size that are 120VAC also. Just searched Amazon and found several.
You certainly answered some questions I had about the conversion. Thanks
Thank you for doing the conversion and showing us the results! Definitely an eye opener comparing the penetration results between the stock AC and the DC- with only a rectifier! Would be interesting to see the results with adding the capacitor you mentioned perhaps doing to yours.
I know you explained how you spliced in for adding the rectifier, but (for me anyway) I’m not sure I understand HOW you spliced in or with what wire I could purchase. You did show us where the connections come from internally and go to on the rectifier. I can solder and put heat syncs on, I just didn’t understand the location to cut and type wire to use.
Thank You Very Much for doing the conversion, showing us the component to do it cheaply and those amazing results!
For cable, I used 4 gauge welding cable (purchased on Amazon). You could use just about any 4 gauge wire, but "welding" cable has more, smaller strands so it is more flexible and easier to work with.
The wire that comes from the transformer is a stiff, solid wire. It is spliced to a more flexible wire that runs to the work clamp on one side, and that runs to the wire feed system on the other side. At each of these splices there is a small, white wire that is also spliced on. This white wire must stay on the AC side. That is all how it is from the factory. I simply cut the flexible cables after the splice. Once you cut both (one for the work clamp, one for the wire feed) you have four ends; two which lead to the transformer, one that leads to the work/ground clamp, and one that leads to the wire feed system. The 4 gauge wire I purchased was simply used to extend each of these to reach the rectifier. Hopefully that makes sense. Let me know if you need clarification on anything.
bigtb1717 That explains it. Thank you!
Thanks for the video and the steps and information behind it.
Thanks to this video, I modified my "Speedway" 90A flux welder by wiring in a 200A rectifier. Immediately I noticed almost no spatter and my welds were consistent, flatter, and immeasurably better than what I was getting from the AC output.
Nice. Glad it worked out for you. One thing I didn't really cover in the video is that a heat sink and thermal interface material (paste or pad) would be a good idea for the rectifier. I didn't use one for the video, but for long-term use, the rectifier will hold up far better if you are able to draw heat out of it.
@@bigtb1717 Thank you for posting this and mentioning the heat sink. I plan on making my own to fit the small confines of the welder's case. I had to move the main transformer fully aft and mount the cooling fan outside the case just to fit the rectifier. :)
Wow, the proof is all I needed to convert mine, ordering the parts now!
I just ordered my parts. How did it work out for you?
I just did this conversion with just the 200 amp full bridge rectifier omg 😱 day and night difference, almost no more bb spatter, and I noticed a huge power increase, soo much hotter and soo much more penetration with .035 flux core maxed out wow 🤩, so with 30 bucks for 200 amp rectifier holy moly soo much smoother arc and like 90 percent less spatter totally worth it and this video confirms it
Great presentation
awesome video bud! Thank you.. I got this welder yesterday wish me luck.. lol
Some say DC Electrode Negative is the trick with that kind of welder. Ty for the info
i absolutely loved this video, thanks man. i love messing around with welders. i modded a clarke mig 150en with a spool gun, and modded a cheap Chinese arc welder to run scratch tig with foot pedal to control amperage,just for fun, both working great.
Start collecting transformers out of microwave ovens (MOTs).
Tear out the secondary coils (real thin wires) and replace them with about 14 or 15 turns of 8AWG. Hook up four good sized ones in parallel if you want to run it 120V. Or connect 2 in series and the other 2 in series, then both of them in parallel if you want it 220. (These connections are for the primary coils only. Keep all the secondary coils in parallel.)
To give you an idea on how it works...
Microwave ovens need about 2200 volts to work, not alot of current. Arc welders are the oppisite. They need more current and less voltage. So the primary coil in both the ovens and welders stay the same, but the secondary are different. Many turns of a thin wire in the secondary produces hi voltage, but low current. Thicker wires at less turns produces more current and less voltage. Each transformer should be as close to each other in size, but not really crucial if youre connecting them all parallel at the primary for 120V use. Just make sure all 4 secondaries have the same guage wire and same amount of turns and are all connected in parallel at the secondaries. This keeps the voltage low but increases the current.
You probably already know all this stuff...I sorry. Lol
Lota videos on this though in the case you dont.
@@AngryHybridApe Wow, all that can fit in the welder cabinet?
Very good video.
Ok so I did mine and the only issue I had was I didn’t plant out the mounting of the rectifier correctly so that when reassembled, one of the screws that hold the pos. Lead on the rectifier was hitting the big metal part (transformer?) in the welder and shorting it out and blowing a circuit when 8 pulled the trigger. So I had to find a couple pan head screws to use and it gave me the clearance I needed so it wouldn’t short itself out. Did a few test welds and what a difference this hack makes. A lot less spatter, and stronger welds plus... when I used to run it as stock, A/C, if I tried to run a bead more than 4 inches or so long, it would pop the 20 amp circuit in my garage... now I can run them all I want with no problems. The only thing I did notice, don’t know if it’s good or bad was that I used to be able to run it on “high” with a wire speed of 7 but now, it sputters on 7 but works great on 4 ...go figure. But I am happy with the turn out... it’s a lot better welder now.
this is some great info I have the harbor freight flux welder and its absolute shit I will be doing this but ill use a dedicated heat sink thanks for the info what size was those terminals you used
the biggest problem with doing the conversion the way it's done here because of exactly what he pointed out, the current for the wire feed circuit is pulled right from the transformer with the current for the gun and because the connectivity and penetration is so much better after conversion so much more current goes out to the weld that it ends up starving the wire feed circuit burning out the pcb, the only successful HF conversions that actually last are the ones where they also added a separate transformer to run the wire feed and increased the cooling and lastly a large heat sink for the rectifier is a must, big cap also helps smooth out the current. do the conversion right and the HF welder will out weld any of the lincoln 115v welders...
I got the Jobsmart 125 MIG from Tractor Supply. About 10 years ago.
Similar transformer type, AC output flux core by appearance.
However mine does use a seperate transformer for the wire feed.
My wire spool loads from the side.
I had plenty of room to bolt the 200amp bridge onto an amazon heat sink about 4x6 inches thats near an inch thick.
Bought a metric tap and used the machine screws that come with the rectifier. And some thermal paste.
Mounted the bridge/heat sink near the fan with lots of room for airflow.
F.Y.I.
Stated output on the front of the Welder cabinet says: "27.1vac @80 amp high."
"17.1vac @40 amp low".
Adding the rectifier you, subtract 1.4 vdc across the forward diode pairs from stated voltage.
And a 140 watt drop in power on high.
So, it's still a weakling voltage machine.
Volts should be 50 vdc open circuit.
Next time buy a Inverter type for 3 X. more $.
I have this exate machine and rectifier and your video is the only one I've been able to fine of this exact model. can you show me or explain how the min max switch and power switch is wired? I made the mistake of unplugging everything during a conversion and don't know how to reconnect everything. I'm pretty close to having it hooked back up properly but I can't get the Wire feed to ingage and I keep blowing the breaker.
Great video. I'm planning on converting my harbor freight welder next week. I have just 2 quick questions about the welder. First, where do you connect the white wire for the wire feed and second, how has the welder been working for you because I see other videos where they are using transformers and other crap which is to me over kill. I like your way because you just use the rectifier only. Again, great video and thanks. Your boy Eric from So.Cal.
I just left that wire where it was. Just make sure that if you do cut or disconnect that wire that you re-connect it on the AC side of the circuit. I simply connected the rectifier after that wire and all was well.
I honestly haven't used the welder much. There shouldn't be an issue not using a capacitor or inductor. Using them just smooths out the arc. But the way I did it was just for proof of concept and testing, not for long term use. If you want it to be reliable you should install a heatsink on the rectifier and use some type of thermal compound between the rectifier and heatsink for proper heat transfer.
Just watched this video. You can use a thick piece of square or rectangle aluminum dimond plating for a heat sink from menards or Lowe's . Just put the dimond side facing towards the metal plate your going to mount the electrical box to then between the aluminum plate and that electrical box you installed put some heat sink compound between the two to help wick away the heat. The gaps between the diamonds act as passage ways for the air to flow through to help wick away the heat . On my harbor freight mig welder i changed out the ground clamp to a better quality clamp with a stronger bit and oiled the rotating shafts and bearings . I also buy rolls of mig wire from menards since its made in america and if you buy 3 or more it drops the price from 17.00 something 16.00 something a spool. I buy the small spools . Menards is cheaper on rolls of wire compared to harbor freight or other places. I also use a heavy gauge extension cord when welding. When your weld plates like you did your suppost to angle grind the edges of the plates : V shape to make a better stronger joint/seam weld.
Are you saying I should have bevel the edge of the vertical piece on these joints?
If you are trying to get a full penetration weld, such as on a butt weld, then beveling can help and may be required. But with a fillet weld on a "T" joint or an inside corner joint in general, beveling isn't always practical, and it isn't normally done as far as I know. There may be situations where it is done, but I don't think it's typical. With an inside corner joint the fillet size determines the strength of the weld, and many weld specifications will call out the weld height and leg size for the fillet on an inside corner joint. With something like a thick pad-eye or similar situation, a bevel could be worthwhile. But with a typical inside corner joint like I show in this testing, I haven't seen beveling done.
But if I'm missing something, let me know. I'm always willing to learn, and if there is a common procedure of beveling inside corner joints that I've missed, I'm all ears. Thanks.
Sorry, but your logic in using diamond plate as a heat sink, is flawed. What you want is maximum surface contact between the rectifier body and the surface it's mounted to. The air gaps caused by the diamonds on the plate material won't "wick away" the heat, as air is a poor conductor of heat compared to metal. You are correct with regard to heat sink compound.
Thank you so very much. I have the 90 amp model and it is pretty much useless at anything more that sheet metal. Have you considered adding Dinse plugs to allow a conversion to stick welding also? 3/16" rods would be well within your 125 amp range and you could weld DC+ or DC- and use almost any rods out there...
i have the 90 Amp version too.... i wish he would have answered your question about stick welding... it would be cool if it could be done.
Thank you for showing how to convert it from a/c to d/c . How do you cut those wire and how do you connected them together
I cut the wires with a small wire/cable cutter I have. It's just a little hand-held snips made for wires. You could also just use a pair of side-cutters. I soldered the wires together and protected the connections with shrink tube. The ring terminals I crimped on, then soldered.
bigtb1717 thank you !
Great video and demo!
What's your thoughts on doing this modification for spot/butt welding thin gauge sheet metal? I'm restoring a 16 Gauge exhaust system and want to reduce the chance of burning through.
Would this assist or should I just keep practicing on scrap pieces (16-18 Gauge)?
After the conversion it will weld much smoother, but I don't think it will prevent burn-through on thin material very much. It might help a little, just due to the more consistent arc, but I think practice and figuring out a technique that works for you will be more important. The limited setting adjustments on this welder are what is going to hold back its performance on thin material more than anything.
What size wire are you using? If you are are using 0.035" wire by chance, moving down to 0.030" wire might help a tiny bit as well.
@@bigtb1717 Nice, thanks for the soliid info. I was using the genertic 0.30 but got some brand name 0.30 recentley. Notice the feed roller was set for the 0.35 initially from the store. Was just practicing on 16G. Getting better!
now I understand. thanks
I was excited to see the posting of this video. Seeing those results I personally think that the conversion is worth the effort even if it's only installing the rectifier. What wire were you using in this test? Is the welder on a 20amp circuit? Last question, is this machine the newer 125 or the older 90 machine? Thank you for posting your test and results.
It is the newer 125A machine. I do have it plugged into a dedicated 20A circuit on a 20A breaker. Edit: Also, in previous testing I measured 130-140 amps of output from this welder when plugged into the same outlet, so I don't think the supply is holding it back any more than any other 120V circuit would hold back any welder.
If someone already has this welder and can't afford something better, I agree that it's a worthwhile modification. In fact, if it were my only welder I'd probably get a capacitor for it as well. Should smooth out the arc. If someone is just starting out, it might be worthwhile to look into other options, vs. buying this one with the intention of modifying it. We're spoiled for choice these days.
Oh, and I was using Lincoln NR-211MP wire. Common stuff, picked up at the local big box hardware. I like that wire a lot better than the stuff that came with the welder.
@@bigtb1717 I agree
bigtb1717 I have the 90amp version but haven’t used it YET - haha.
You mentioned “other options” if purchasing new. What DC flux core welder would you suggest for someone like me who is budget restricted?
Keep in mind, none of the other options are nearly as cheap as the HF welder. I will be reviewing the Century FC90 soon. It used to be $169, but it is $199 now, as far as I can tell. It is a DC output welder and I'm optimistic about performance, though I have barely used it so far.
Lincoln has a DC output flux core for around $270. Quite a step up in price, but it works well and is simple and reliable. I haven't looked into other options much, but I'd look into Everlast, Razorweld, Klutch and possibly a few others I can't think of off-hand. You may end up still deciding the HF fits your budget best. It is definitely the cheapest.
I see your rectifier is rated at 200 amp, 1600v. Amazon has several flavors of that are there any other specifics I should know before ordering?
Thanks for this video.
I picked the one I did based on amps (200A gives a bit of breathing room, for hopefully better reliability), it had screw terminals, and it was prime shipping from Amazon. You are only dealing with voltages under 50V, so 1600V is way overkill, but it's probably overrated anyway. You just need a single phase, full-wave (most you'll find are full-wave, but just make sure you don't get a half-wave) bridge rectifier that can handle the amps and volts. Nothing else special about it. There is a 150A rectifier on Amazon for under $14 shipped that is smaller and would be a bit easier to fit inside. It is from the same seller I ordered from, and I would have tried that one first, but I decided to go up in amps.
FYI, I used 4 gauge wire.
I didn't do this yet, but I may end up putting a thermal pad between the rectifier and the side cover of the welder. Neither surface (the back of the rectifier or the welder panel) is very flat, and a thermal pad would improve contact and may aid in heat transfer. Something you may want to consider as well, depending on where/how you are going to mount the rectifier.
Good luck and be careful. Safety first when dealing with electrical components.
bigtb1717 Thanls for the specifics to look for when purchasing the rectifier.
is 'tied in' a welding technical term? I googled it & didn't find anything similar to what you're explaining. I'm assuming you're referring to the amount of penetration, but I'm not sure. Can you please clarify? thanks
Sorry, I don't know where I picked that term up over the years. But you pretty much have it. "Tied in" just means that the the weld metal melted into and mixed with the base metal, at least slightly. It's basically just a way of saying there was at least some, small amount of penetration. So if the toes are "tied in," then the base metal melted at least a tiny bit at the toes and the weld metal and base metal mixed together a bit. So the two are "tied" together.
If something wasn't "tied in," then the weld metal is essentially just laying on the base metal and the base metal didn't melt at all. The two may still be stuck together somewhat (similar to a braze or solder joint), but it isn't as strong of a connection as if the base metal had melted and mixed in with the weld metal, essentially becoming one.
I’ve got a strong feeling after using this same welder they’re only for thin gauge sheet metal
Did you add that fan also? How's that doable? that's an AC connection to the stock fan. Those CPU style fans are DC right?
I did not add a fan. That is the stock fan. I didn't inspect the fan closely. But it may be a universal, brushed motor, or it could be an AC motor fan.
I see you've done videos on the Amico TIG welder, have you considered doing one on their super cheap stick one?
I haven't, but I'll look into it.
@@bigtb1717 Their arc 140 is $99 USD and I'm curious on the penetration. A friend got one a while ago and it's one of the cheapest on Amazon.
Just FYI, I ordered an Amico ARC140 and should have it in a week or two. Once I have it and get time, I'll be testing it out and making a video or two about it.
can you do positive ground with this setup?I have heard that flux core runs better less splatter
Yes, that is how I had it set up. Flux cure runs really poor on electrode positive (negative "ground"). Converting to DC and running electrode negative (positive ground) runs far better. AC flips polarity 60 times a second, which is one reason it runs poorly with flux core. 50% of the time it is electrode positive. Electrode negative runs smoother, less spatter and better penetration.
Thanks, I'm gonna give this a shot. as it stands right now the welder is pretty much useless.
what are your thoughts on using 8 awg for the wiring to/from the rectifier & cap? I'm trying to get this conversion done, but accidentally purchased 8AWG THHN wire instead of going with 4 or 6 awg. Considering the short runs, should 8 AWG be ok, or will I necessarily need to go bigger?
With the short runs they would probably work okay. 8 AWG will technically have well over twice the voltage drop, compared to 4 AWG. But it's probably not enough to meaningfully effect how the welder runs. The main factor is that 8 gauge wire will heat up much faster. It still may not be be an issue for smaller projects. If you have a big project and weld a lot, you may overheat the wire insulation. It would depend on a lot of factors, like how long the wires actually end up, if they have any airflow from the fan over them, etc.
Woukdnt use thhn. Stranded is best.. oxygen free 0awg grounding wire neant for car stereos would be cheapest and best..
Great video. Please consider a short tutorial on the butt and ring connectors you used, how you crimped them and links to purchase them. I'm thinking of replacing my cheap Chinese ground cable with a 6 gauge cable. HF has 16 ft, 6 gauge jumper cables for $15. Do you think replacing the ground cable would help? Cheers
Replacing the ground cable probably wouldn't help much. Also, the stock ground cable is 4 gauge, so 6 gauge would be smaller and would be a down-grade.
@@bigtb1717 My welder came with an 8 gauge ground cable, so I'd be stepping up in gauge.
@Dominique Hardie Awesome! Thank you so much for the info and I'll look that up now. The cable that came with my welder is only 8 gauge. I purchased a nice clamp from HF, got a 24V transformer for the wire feed motor, a 150amp full bridged rectifier and a dines connector for the ground. Cheers brother
@Dominique Hardie Just ordered the 6 gauge wire. $1.05/ft, free shipping and made the USA. Thank you again and hope you had a great Thanksgiving.
@10:45
My Chicago Electric 125 welder from Harbor Freight came with instructions that said it was a 20% duty cycle machine out of the box.
This counter renders it for spot welds or what you do a "long-run" you can go ahead and take a coffee break for 5 minutes. Not for the one making a living as a welder.
Doing this conversion would I be able to weld thin metal like fenders on cars and stuff like that or would it be too hot now?
I never tried welding really thin metal with it. You can still turn down the output after doing this, but it doesn't have infinite adjustment of the voltage, so I can't say how thin of metal you could weld before or after this modification. The modification will allow it to weld smoother with far less spatter, which I think would be a good think for auto body work, but you certainly don't need extra penetration. If that is your main use case, I probably wouldn't bother with the modification.
@@bigtb1717 wouldn’t say that would be my main use case I want to be able to do a lot of things with it but auto body is definitely one of them maybe I’ll just put the Lincoln wire in it and upgrade the ground clamp and get some anti spatter spray
Great video, but for about $70 more wouldn't it make more sense just to get the Century FC-90?, and have to mess with buying all these additional parts to upgrade the HF model?
I can’t remember if I said it in this video, or one of my others on this welder, but my feelings are that if you already have this welder and want to convert it or just thnk it sounds like a fun project, by all means. But I wouldn’t recommend buying this welder with the intention of converting it to DC. Personally I’d recommend just buying a more expensive welder.
The century is an inverter. One component goes gad then you need a new welder; this one however can be turned into dc with a rectifier bridge, a transformer is way more reliable than inverter
I like mine how it was made just don't like the copper coated wire is all takes more energy to heat it up and doesn't leave good weld lines
Hey brother... which gauge wire did you use? I did this conversion a couple years ago but forgot wire size... The wire I purchased on eBay was not oxygen free and it oxidized at the terminal connectors and the unit has failed😢
Oh, it has been a while, but I'm pretty sure it was 4 gauge.
@@bigtb1717 that's what I thought 🤔 too...just wanted confirmation 😜 thanks for the reply sir
@@mariocooldude9092 No problem!
So would not using a cap damage the welder in the long run?
No, it won't hurt anything. A capacitor can help smooth the output, for a smoother arc. But not having it won't damage anything.
One question. I have see other tutorials and they use capacitors to smooth out the current the machine puts out. Is it absolutely necessary or can I just go without it?
I didn't really intend this to be a tutorial, just a basic as possible conversion to test performance. If you are converting one for normal use the main thing you should do different than me is that the rectifier should have a heat-sink and some thermal compound between the rectifier and the heatsink. It will need something to keep it from overheating. A capacitor isn't absolutely critical, but it will smooth out the voltage and make the arc a bit smoother, so it is a good idea. It's also a good idea to have a bleed-down resistor across the capacitor so it will drain down the voltage when you stop welding. Otherwise the wire could stay live from the charge in the capacitor when you stop welding. You could leave out the capacitor and get by. Even without the capacitor it will still weld better than it does out of the box. Some people also use or create a simple inductor to smooth out the amperage as well. Again, not critical, but it may make things run a little smoother.
Thats the point of the video as far as i can tell, he wanted to show that no, smoothing caps arent 'necessary" for changing output using a full wave or bridge rectifier, its just not clean output but any kind of dc will be much better than what the hf spatterwelder can do
Will it be better if you put 2 of the 200a bridge rectifier in parallel , might last longer
You could. I think the more important thing would be to put a heat-sink on the rectifier. I didn't put one on mine for the video because I mostly wanted to see how well it would run. Barring any quality or overrating issues with the rectifier, I think a single one should hold up okay if it has a heat-sink.
Putting diodes in parallel is not a good idea. It's almost impossible to get the current to divide between them equally. You'd be much better off using a 250 or 300 Amp rectifier.
With this mod you can still use the reg 20amp outlet like stock form right??
Yes.
Can you post a link on where to buy or just an overall search criteria for me to use I'm new to welding for the most part and am not able to make this welder perform very well stock.
Are you looking for the rectifier? You could search Amazon, eBay, etc. for 200a full wave rectifier, or 200a bridge rectifier. I hesitate to post a link because things change so often with these types of listings, it may break or simply take people to the wrong place at some point.
@@bigtb1717 I got ya yea I found one on amazon just looking for a capacitor
Yes it's the cheapest but you all will want to do a heat sink, compasidor, bleed resistor and a ferrite core and if you have the older welders you will want to put a plastic shroud around fan blades to pull air in thru back vents
Does this improve on the duty cycle of the welder? Or is the duty cycle linked to transformer and so it will stay the same?
This won't change the duty cycle. As you say, it's still going to be tied to the transformer, which is still doing the same amount of work.
@@bigtb1717 Thanks
@@bigtb1717 Does doing this conversion reduce splatter?
For sure. Flux core will always have spatter, but AC output will increase spatter noticeably. Converting to DC will provide smaller spatter BBs that don't stick quite as hard.
I am so sorry for bothering you, but I had done everything you did to specs. Everything was fine up until the point where I turned on the welder and pulled the welding gun switch...nothing! I tried it again...nothing. I removed the motor from the welder to see how f it was bad, turns out it was still good. So whatever I did it's not getting any power to the motor. The relay is good ,the 2 fuses inside are good and not blown and there's nothing I can see physically that is wrong. What did I do wrong?
It's hard to say for sure what is wrong. The two control wires on the output of the transformer, did they both stay connected where the were? Do you have a multi-meter? If so, do you get any voltage on the wire when you pull the switch and the motor just doesn't run, or does the welding output not turn on either?
so i have the 120v 90 amp version of this...just to make sure, if i do this mod, it will then be DCEN when done? someone said it already is DCEN, that ALL Flux core welders are, Migs are not. is this true? i have a bunch of flux core wire that says you need to use DCEN thats why i ask. thanks!
After the mod it will be DCEN. You do have to ensure this when you do the mod. The rectifier will have a positive and a negative output terminal. You have connect the negative terminal to the wire feed system and the positive terminal to the work/ground clamp.
There are definitely flux core welders that are not DCEN. The 90A welder you have is AC. Most self-shielded flux core wire is designed to work with DCEN, so it doesn't work very well on AC. That is why this conversion helps so much, because stock it is not DCEN, it is AC. Converting it to DCEN helps a lot.
Solid wire, gas shielded MIG is normally run on DCEP for steel and stainless, DCEN for aluminum. Most MIG welders can be switched between EN and EP for running different wire, including flux core. There are even some flux core wires designed to be used with shielding gas and they use DCEP. So there are a lot of different situations. Most commonly, flux core is run on DCEN and MIG run is DCEP.
Awesome, thanks a lot!
“Welder turned down a little bit” There is only low and max settings. Were you welding on the low setting?
No, I had the voltage set on high the whole time. I only adjusted the wire feed speed.
bigtb1717 ok cool, Thankyou
It seems that any knowledgeable welder suggest switching the DC polarity on a flux core welder, why aren't they just built this way? Or included with a switch?
This particular welder has AC output to save cost. In this video I convert it to DC output and wire it for electrode negative, which is the polarity that works best with most self-shielded flux core wire. Most flux core only welders that have DC output are built to have the proper polarity for flux core and do not need to be switched. Solid wire, gas shielded MIG uses electrode positive and most MIG welders that can run gas shielding will be built with a way to swap polarity so you can run MIG or flux core.
I got my dc bridge today. On the ac side you didn't say what side goes where. It might not matter being ac but does it?
Nope. On the AC side it doesn’t matter which wire goes where.
@@bigtb1717 didn't think so but..
Hey, better safe than sorry. Hope it all goes well. Let me know how it turns out.
@@bigtb1717 I need some 8 gauge wire and connectors but also I think I'm gonna go all the way and do a cap and resistor, except im an idiote and im unsure of what to go with there too. Im fould a cap that is 47000 uf 50v and I think I can run two 10v 100 resistor. I have them in my cart but haven't purchased them yet. What are your thoughts?
So I got the wire and stuff but couldn't wait to finish my bike. All I did was change the ground clamp and that was huge. My welds are really good. My fabrication skills... not so good.look like I bought Harley parts from China.hahs but with some tweaks I managed to make them work.
Help.... lol I’m a little confused about the white wires... you said to do the splices AFTER the white wires, then you said What ever you do, makes sure they wind up on the A/C side of the rectifier. So in other words, they don’t change at all? They come out of the transformer and go to where ever... and that’s how they stay? We don’t need to switch them around like we are the big wires ? Just want to be sure. Thanks!
Correct. They can stay right were they are. By "AC side of the rectifier" I meant that they should stay on the AC side of the circuit, not that they should necessarily be connected directly to the rectifier. You just don't want them to be on the DC side of the circuit. Hopefully that makes sense.
And now, I finally got my rectifier in from amazon and I looked at it and there are no markings to tell me which side is ac and hitch is dc lol there’s just + and - but one side does have a little ~ next to each terminal...
@@hdrjunkie The + and - mark the positive and negative on the DC side of the rectifier. The ~ symbols are the AC input side.
Great!! Thanks again for the help!
What gauge wire is it? I need to know for the lugs
I think I used 4 gauge. With the short lengths, you could probably get away with 6 gauge.
@@bigtb1717 thx
One comment one question:
First, the question - how much splatter reduction did you see with this mod? I’m planning on doing this and reducing the splatter is of primary importance to me as I have a Hobart stick welder that I use for anything structural or that needs deep penetration. I’m planning on forgoing the capacitors as well because I don’t want to put the money into it AND IMHO, it’s dangerous if you don’t do it right! I think anyone who throws a capacitor in there without a system to diffuse the leftover charge is playing with fire. Eventually, you’ll forget and grab the ground while your still holding the electrode.
Second, the comment. I see a lot of people out there complaining about these welders being useless. That has not been my experience and it makes me wonder if it’s the welder and not the machine. First off, get yourself some decent wire. I use Lincoln electric flux core in .030 and .035 and it works great. Less splatter and good beads. Second, clean the surface!!! This isn’t stick welding on 220 where you’re going to punch through grease, rust and even paint without issues. Third, and I think this is likely the problem with most people - learn how to run a good bead first, preferably with a stick welder. I use my flux 125 on all sorts of materials and it works pretty good as is, out of the box (minus the splatter) especially since I got it for a $40 open box special. Turn down your wire feed to 5 or 6. Take your time and let the heat build so you create a good puddle. Stitch it back and forth. Make sure your tension is set correctly - i.e. you should be able to stop the wire with light pressure from one finger. I welded a engine cart together last week using this welder and some square stock and it’s holding my 800 lb Jeep 4.0 engine right now, solid as a rock.
Spatter is definitely reduced. Mostly the spatter is a bit more fine (smaller spatter bb size). The AC output results in larger spatter that is often more difficult to remove. With DC output it's definitely better. There is still spatter though. But there is less.
I agree that if you install a capacitor it should have a bleed-down resistor to drain off the voltage. However, I would say getting flashed is probably the bigger danger as compared to shock. The open circuit voltage on a welder like this is far lower than on a stick welder, and a stick welder output is live all the time. Still could get shocked, but I think it's far more likely to simply get flashed after lifting the helmet or before lowering it if the wire touches the table or work piece.
I agree that this welder is very capable for the money. Up to 1/8th of an inch thick material it works very well. Above that it gets very little penetration. Technique and settings can help achieve a decent looking weld, but I have found the penetration to be seriously lacking on 3/16" thick material. The A/C output really holds it back. With DC output it runs smoother and burns in better. But again, that doesn't mean it can't make welds that are strong enough for a lot of projects as it is out of the box. I think people go a little overboard in both directions when talking about this welder. Some people seem to adamantly claim that it is just as capable as any more expensive welder but people just want to justify their expensive welders so they put this one down. Others simply insist it's 100% junk. The truth is definitely somewhere in the middle. The machine definitely has limitations and it simply isn't as capable as a 240V welder, or even a similar welder with DC output. But within its limitations it works fine.
bigtb1717 good to know about the shock vs flash. Now that you mention it, both of my comments relate directly to another instructional video I watched today in that 1) the person who made the video flashed himself the first time he used the welder and 2) he judged the upgrade as poor because both the “beads” he put down looked like garbage - though I have seen a lot of comments knocking this welder as well. The gentleman in this other video literally just pushed the trigger and dragged the electrode for a couple seconds on the metal surface. Zero technique, zero patience. I have also found that this welder works great for the 1/16 and 1/8 tube I usually use to fab little things around my shop. If anything, I find the conservative nature of this welder beneficial in that I’m not blowing holes through square tubing left and right. Like you said, the bottom line is that this welder functions well for what it is, but is limited in versatility and will NOT weld things for you or lay perfect beads without some effort and knowledge! It’s been very handy for me around my shop though - it’s my go-to for quick tack welds with the shelves I just built, as well as thin tubing. I’m hoping that the conversion to DC will eliminate enough splatter to allow me to use it to weld frame stiffeners to my Jeep, but I’m keeping my expectations tempered. I guess that since I bought mine for a song, I tend to fall on the over-optimistic side of the argument, though!
I have one suggestion/comment, and I certainly don’t want this some come off as condescending, but I’ve heard and found that, contrary to what many people assume, turning the speed down on the wire feed will allow for deeper welds. As I understand it, adding new wire/steel to the puddle has the effect of cooling the puddle, and therefore the slower you add wire, the more penetration you get (within reason). This is because: 1) the puddle reaches a higher temp because you’re not constantly adding metal and 2) the bead builds slower so you can stay in one place longer. I’ve found a wire speed of 5 to 7 to be good for most applications, with a tendency for 6. Additionally, in regarding to upgrading or adding a cooling fan - I chose to keep my secondary cooling fan on a separate circuit. Meaning I had a 115 vac muffin fan that pushes about 40 CFM laying around and decided to power it with an independent plug, the logic in this being that if the goal is to extend duty cycle, I’m better off with an independent power source rather than utilizing the welders system. This may not make much of a difference in practice, but I am a novice/hobbyist.
bigtb1717 and I absolutely agree about it not being a 240v. My Hobart stick-mate is 240 and it blows through grime, rust, and paint and still gets solid welds.
I'm always open to comments and suggestions. I understand what you are saying about heat and wire speed. In general, increasing the wire feed speed _should_ increase the amperage, causing a hotter weld. However, if the welder is near max output and you increase wire speed it could cause issues. There is definitely a point where piling too much weld on top will result in the arc basically just heating the bead, rather than burning into the base metal, but often that's from too slow a travel speed for the wire feed rate, rather than due to wire feed rate itself. I have a video where I tested this welder with different combinations of travel speed and wire feed speed settings, cutting and etching each joint and comparing penetration. Actually, I think one of the sets of etched welds I show for comparison in this video is from that testing. One way or another, I've always heard that with welding, never say never because there are exceptions to everything.
Ive heard to reduce splatter, you need to switch to electrode negative, so your hottest point is the metal you're welding into, rather than using 70% power on the tiny wire. Ive also heard that these Chinese machines (or any smaller welders, potentially) need to "warm up" before it starts to penetrate as intended and not splatter as much. I have the dinky 90amp version of the flux core welder and it takes a bit of time before it really starts to weld easier (same techniques/settings, just a warmed up machine).
Thank you for the video, I'd be interested in seeing more tests on this. I'm curious, you went DCEN correct? Because some set it like it's regular MIG not knowing the difference.
Yep, DCEN. I went over it pretty quick in the video, but I did mention connecting the positive terminal on the rectifier to the work clamp and the negative terminal connected to the wire feed.
I've made the mistake of running self shielded flux core on DCEP in the past, and it runs worse than AC.
@@bigtb1717 I must have missed it, but yeah. My friend bought this machine and when I used it I immediately decided it needed to be converted, so I've been looking into there simplest way to do so and your video was very helpful.
bigtb1717 You mention you might put a capacitor in. Please tell me why, what size/type (perhaps a link to the one you would suggest) and how you would wire it in? Thank You Very Much!
I don't know how much you know about how AC power works, but the voltage is a sine-wave pattern that alternates back and forth between positive and negative. The rectifier changes the negative portion to positive, so the output is always the same polarity, rather than alternating. But since the source is a sine-wave, the output from the rectifier is constantly pulsing.
A capacitor can help smooth out these pulses and in turn, smooth the output of the welder. A capacitor would get wired in parallel with the DC output. It would ideally use wire as large (or nearly as large) as the rest of the circuit. I think 50,000 uF or more is generally recommended. A capacitor stores voltage, so you would also want to connect a bleed down resistor, otherwise the output can stay live after you stop welding. Many people add an inductor as well. Leaving out these extra components is why an AC output welder can be so much less expensive.
That's why I wanted to see how much difference just a rectifier made, without also having to stuff a capacitor, inductor and related items into the welder.
@@bigtb1717 thank you for that explanation. I've seen videos of the much bigger mod. So if this mod fails and I'm assuming the bridge would go first. Would I just replace it and try again?
I did the mod but now the welder is always live as opposed to before where it only sparked when I squeezed the trigger
Strange. That shouldn't have changed. Is the wire feeder running constantly as well? If I remember correctly, the power for it came from the output transformer.
@@bigtb1717 I think I might have wired something poorly, I had to improvise because I couldn’t find 4 gauge butt splices
@@bigtb1717 it’s also super inconsistent which further leads me to believe I wired it up poorly
@@bigtb1717yeah I wired it up again and it still is always live, idk where I went wrong. I wired up the clamp to negative, the gun to positive, and does it matter which side goes where for the ac parts bc I just did them at random?
I have a brand new 125 never used yet, not a welder so I'm getting as much advice as I can here. I cant weld until Saturday because my helmet isn't here yet. So I could the dc bridge and bought it and a bett ground clamp for 26 $ on Amazon free shipping if you buy the clamp. Hows it holding up,and have you used it much? And as a newbie should I do it?
I would try it as-is first. On thinner stuff (1/8") it will do okay stock. If you do decide to put in a rectifier, I would recommend getting a heat-sink for the rectifier. I didn't use one because I wanted to easily and quickly see how much difference a rectifier alone would provide. If I was going to be using the machine a lot, I'd want a heat-sink. On that note, I haven't use the welder much since the conversion.
@@bigtb1717 I have a piece of aluminum does that qualify or are we talking finns?
A block of aluminum might help a bit, but something with fins would be best.
@@bigtb1717 like everything else I found one on Amazon. Thanks again for all your help. My helmet should come today and I have a whole lot of scrap stuff ..so here I go.
@@davidfellows6250 Cool. The smoke from flux core builds up quick. Good ventilation is important and is easy to overlook. No matter how cold it is I open the garage door when I weld flux core. Also, fumes from anything zinc plated can make you sick, so be mindful of that when welding anything zinc plated. Also, never clean something you are going to weld with brake cleaner. The fumes from super-heated brake cleaner can be extremely poisonous. Just something some things to think about. Be safe and have fun!
Do a video with DC and Amps output with the Fluke.
I had a big project for work and then I went on vacation. I should have a few calm weekends coming up (hopefully). I plan to do some welding videos soon. It shouldn't take much time to check the DC output of this machine once I get back to it. I'll add that to the list. Thanks.
@@bigtb1717 Great, I'm looking forward to seeing the conversion output.
What wire gauge did you use?
I used 4 gauge welding cable.
INE brand which leaves beautiful welds and size 030
I notice I'm commenting on a video that is several months old, but I have a few questions if you can help. First one is the connection of the rectifier. On the AC side does the connections matter? Is there a positive on negative on that side? Then on the DC side you make the gun portion connect to the negative and the ground clamp connect to the positive?
Also, will this still only arc when the trigger is pulled or will it be hot without trigger pulled? I've seen several videos of people saying after installing the capacitor they needed to discharge it since it was still live.
There is no polarity on the AC side. On the DC side you are correct, negative goes to the wire feed/gun and positive goes to the ground/work clamp.
If you install a capacitor it will charge up as soon as you start welding and will stay charged when you stop, leaving the wire live. If you install a capacitor it is highly recommended that you install a discharge resistor across the capacitor. I'd have to do a bit of research to get recommendations for resistor ratings. The resistor will cause a bit of draw on the capacitor and will drain it down when you stop welding, so the wire doesn't remain live.
bigtb1717 thank you!
I like your ideas,,, and I have a new HF 125 welder, want to use it for thin gauge metal without all the splatter. Question: How about using a 300 amp 1600 v rectifier to decrease the amount of heat stress and a heavy duty induction/coil to smooth current out a little.? $25 on ebay
An inductor can be helpful, but how large or how small an inductor can make a difference in the arc. It's difficult to say just how large or small an inductor you would want to use. You probably wouldn't need to buy an inductor, I think some people just wind a wire around something inside. I've seen on forums where guys talk about how many turns of wire they use. I'd say a capacitor is probably just as important for smoothing things out.
A 300 Amp rectifier is a good idea. It will be operating at approximately one-third of its maximum rating and as a result, have a longer lifespan.
@Mere Woman;
Thin gauge metal? Buy an Inverter machine that can dial down current to 25Amp.
Spend About $75 more than this welder.
But If you try this mod, I believe you will need:
A large aluminum finned heatsink, screwed to the rectifier base with a thin film of thermal paste in between. And positioned in the case for fan airflow to dissipate heat.
After the mod, it's still a 20% duty cycle machine. 2 minute weld time, followed by eight minute cool down.
An Inverter machine may have a 60% duty cycle.
Most convert to DCEN, but DCEP gives deeper penetration.
The common self shielded flux core wires that people would run on this machine are going to run on DCEN. DCEP runs very poor with self shielded flux core and would be extremely unlikely to give satisfactory penetration. There are some gas shielded flux core wires, and some specialty self shielded flux core wires that run on DCEP, but I don't know of any that could be run with this welder.
I know this is a L O N G time after your video, but...
Could I bolt a square flat piece of aluminum to the place you bolted the rectifier first, then bolt the rectifier to it as a heat sink? The aluminum dissipating the heat faster than metal. Or is that too simple minded?
Oh, thanx for the help and tests on things to show real life results. Good stuff!
A plate of aluminum would definitely help a little, particularly if it was flat and could draw out heat more efficiently, but something that was exposed to the outside of the case or to the airflow of the fan inside would be better.
@@bigtb1717
Good point! Yes, it was my intention to use a flat piece of aluminum about a quarter inch thick and bigger than the base of the rectifier so it's bolted first, then the rectifier onto it. Of course, cutting a square hole in the side along with the aluminum would ensure a good cooling!
4 diodes =0.7x4=2.8V
P=VI cos Theta,; assume Cos(theta)=1. Hence, Ploss=2.8 x125A = 350 Watts loss, very warm ! 🥵
@@atran3462 Yes, this welder is poorly conceived as built. However, supply chain from China sells many, many Bridge Rectifers. Adding much extra profit.
4 diodes =0.7x4=2.8V
P=VI cos Theta,; assume Cos(theta)=1. Hence, Ploss=2.8 x125A = 350 Watts loss, very warm ! 🥵 To avoid thermal runaway, Need thermal grease for reliable
I agree. In my video I just wanted to test the penetration difference, but if you want to do this on a machine that will get much use and want it to be reliable, you will want some kind of heat-sink on the rectifier and would ideally have a thermal interface material between the rectifier and heat-sink.
In early March 2023 I have browser-searched for DC welders with transformer arc generation. I could not find any under $600.00 U.S.D.
Therefore-to put $200 in this $150 purchase price still has you at least $250 to the better and in Illinois you'll have to pay another $60 in sales taxes.
I think i need to snap in a 30 fuse in the box
Can upgrading the power cord to the machine from the stock one help it get more power easily to the machine? My little portable Chicago ele. stick welder has a much thicker power cord on it than my 90 amp Chicago ele. flux core.
I'm thinking, bigger power cord plus this mod and adding a better ground clamp would go a long way. Also, whats your thoughts on replacing the electrode gun and cable with a better one? Or don't bother as it wont make any real difference?
Upgrading the power cord probably wouldn't make a big difference, but it might help a tiny bit. It's probably not long enough to cause much voltage drop, but the less voltage drop, the better. A better ground clamp can definitely help with consistency, and is worth the upgrade, in my opinion. I don't know that replacing the gun and cable for it would be worth the effort. It's not the greatest, but I don't think it's holding the machine back very much.
Good to know... thanks again!
someone needs to come up with a amp control. thin metel pow holes ... lower amps or voltage i guess easier on the dc side to do this.. good video tho i was goin to do this 2 years ago hahhaah have all the stuff .. still not get to it hahah
How can I change the polarity that's the problem
For self-shielded flux core, the "electrode" should be negative. So after the conversion the wire drive should be connected to the negative (-) output of the rectifier and the work/ground clamp should be connected to the positive output of the rectifier.
@@bigtb1717 I know but how do I do it on the 125 Chicago flux welder is what I mean
The Chicago Electric Flux 90 and 125 have AC output in stock form. AC does not have a specific polarity.
@@bigtb1717 ok so if I DC convert it can I change the polarity or no
Yes, once you convert to DC, the output of the rectifier will be DC with + and - terminals. So the polarity can be set properly for flux core when you are installing the rectifier.
I do want to copy this, I know how to connect terminals and solder. The main issue with the video is that all the heat shrink, wires splices, etc, it's all black. It isn't very helpful for someone not familiar with the various parts of a transformer or welder on an electrical engineering level. Knowing my luck, I'd try to do the conversion and blow something up with the welder. The video could be improved with perhaps a voice over, a freeze frame, and some hand-drawn arrows using the before and after shots of the welder's internals. Or a diagram?
Unfortunately, this video was never really meant to be a "how-to" for this conversion, I just wanted to show, in general, what I did. This video was more about showing the drastic difference in performance after doing nothing more than rectifying the output to DC. For instance, at the very least you should also put some type of heat-sink on the rectifier with thermal paste between the two. A capacitor (or capacitors) will also help to smooth the output, though it's not strictly necessary. I could probably make a diagram or a new video if you can't find any other how-to videos out there.
@@bigtb1717 I get that. The unfortunate thing is almost every video I manage to find is about 2 or 3 years old and the presentation is from a post-project perspective. Or the quality of the video is potato grade. Searches for some higher quality video and information lead me to your video. I guess the search goes on, lol.
I actually have a second one of these welders. I’ll consider doing a full, start to finish DC conversion video with it. But it might be a while before I can get to it. I’ve been really busy with work and family stuff, so it might take a while to get around to it.
Why not just buy the Titanium 125, for nearly the same price on sale. It's already DC negative
I agree. Now that the Titanium 125 is available I definitely recommend it over this machine in general, and I certainly wouldn't recommend purchasing this machine with the intention of converting it.
In fact, I have a review of the Titanium 125. It's better in several ways beyond just being DC output, thought that is the biggest improvement.
The Titanium is better in that it is already DCEN. However this welder will take a 10# wire spool where the Titanium will only take a 2# spool. I bought mine before knowing about the AC issue. Ignorance is bliss. I likely would have bought the Titanium, had I known the difference. I did convert mine to DCEN with a capacitor and it made a whole new welder out of it.
Informative, but you repeat yourself and talk way too much.
Thanks for the feedback. Always looking to improve. Cheers!
You don't know how to weld bro. Operator error
What do you think I did wrong, and what do you think I should have done different to make it right?
And you do?
Everyone knows how to do it except the dude getting it done.
@@bigtb1717 i love that he couldn't reply to your questions... shows how good a welder he is...lol.
But it is not "putting lipstick on a pig" as the first video before yours on this DC conversion topic.
If "$xx.xx" raises the value of the machine, them the machine is no longer a "X" value; it value has increased.
If you put a strong running Chevy 454 big block in a canoe, the canoe is now worth more than before the addition of the big-block.
In fact, it could be that an "$xx.xx" investment/modification could increase the machines value by a multiple of the cost to convert it.
The video I watched before your put in a heat sink about triple the thickness of the rectifier.
I did the conversion as basic as possible just to demonstrate the difference in performance, even without anything other than a rectifier. If someone was going to do this conversion with the intention of putting it through normal use, they would definitely want to use a proper heatsink for the rectifier.
In general, I wouldn't recommend anyone purchase this welder with the express purpose of converting it, unless they just wanted a project or something, in which case, have at it. But considering the cost of welders like the Titanium Flux 125, which is better in many respects, I'd definitely go that route over buying and converting this one. But if you already have this welder and want to convert it, you can definitely get more performance out of it after converting it to DC.
@@bigtb1717
Ya- The expense of $50.00 is so much better than laying out two Ben Franklin's plus 10% sales taxes for another machine with my 30-year on-and-off cash starvation situations in my life..
I rest the welder 4/5ths of most times. If I violate, then Inlet it sit for 8x the summation of time violated.
I just have 12-linear-inches to perform. But I just am not getting the hang of it. I am welding 11-gauge cold steel to a hike I made subframe on a 1999 Toyota Solara to change out a bad caged nut..