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Casting a Performance Cylinder head in the Garage
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- čas přidán 19. 01. 2024
- In this video I finally get on to using to tools I have made do casting and Melt some Aluminum.
Check it out and see how I go.
The goal is to double the Horse Power my race bike engine produces with a custom cylinder Head.
Looks pretty awrsome! Couple of tips, dont use PLA. Use something like Polycast PVB. It burns out clean. If you try to use compressed air to remove the PLA ash residue, you can, and it kinda works, but the air pressure required will also wreck the plaster mold. Trust me, i tried. For the finest details in plaster molds, you can use a vacuum table set up. The detail and fidelity you can get is unbelievable. Gravity feeding works, too, but you need the metal to be a little hotter. And great choice with a pouring basin and the runner bypassing the part, but if you still have issues with part filling and dont want to run a vacuum, you need more head pressure. Large, thin walls are most difficult to fill. Aluminum tends to be more viscous so it needs more help. What kind of aluminum are you using? For cylinder heads the go-to is usually a356. Hope this helps and good luck!
Funny you mention that, I'm currently printing out the next design with polycast as we speak.
I was thanking some sort of vacuum setup would make a big difference, wasn't sure where to start.
I'm going to have a look into it as like you said large thin walls are going to be a pain for sure.
Yeah I'm using A356.
Any idea on max pouring temp? The internet tells me 680c to 750c.
Yes this is super helpful.
Thankyou Paul
@@TheMotorcycleForge Pouring temperature is a tricky thing to nail down because every process is different and there are lots of variables. The general rule of thumb is to pour hot enough to completely fill the mold, and no hotter, but that has a problem, too.
I've poured Za-12, an alloy that flows better than A356, into a plaster mold that was gravity fed, like yours, only the metal and the mold were overheated. The mold was above the melting point of the Za-12, and the metal was probably 2-300c too hot. It still didn't fill tiny details. Sometimes the part just has to have help, like a centrifuge set up, or lots of head pressure (much taller mold, part in the bottom, tall sprue which has it's own issues) or a vacuum. You would need a vacuum table and some holes in the bottom of your flasks.
A vacuum table is just something that uses a vacuum pump to suck air through the investment plaster, which should be slightly porous if you are using the correct stuff. This effectively removes air bubbles trapped in the mold, and uses the atmosphere above the mold to force metal into fine details. It works for jewelers, and the results are incredible. I use an off the shelf vacuum casting set up from Vevor to degass the mold and also pull a vacuum while casting. Sounds like you are australian? not sure where you get it there, but there is a Brit with a channel @vogman who build his own set up with a pump made from PVC. He has since moved up to a Kayacast vacuum set up which is the better version of the one I have.
He has some videos that would help you out, especially since the flasks you made would pull a vacuum from the bottom instead of evenly through the walls like a perforated flask. There is a work around and it works fine, i think it's called the "straw technique". Oh and I use pieces of polycast filament as straws and vents, it works great, but blue jewelers sprue wax is must easier to work with in my opinion.
sorry for the wall of text!
-Paul
So much to learn, yeah from what I have read poring temp and mold temp vary a ton between different set ups.
Someone said mold temp half of the alu temp, I'm going to try that next.
I may invest in vacuum setup if I'm unable to cast a full size head, not super fussed about the scaled down one as I'm aware it will be a lot harder.
OK I will check out his video's and see what I can learn from him.
Don't be sorry haha, I need all the help I can get.
Cheers Logan
I was also going to mention vacuum casting, however, the part is large enough that the size of vacuum well he'll need would be quite expensive for a hobbyist.
Que tipo de gesso posso usar
That's freaking awesome
Thanks man!
Something I've wanted to try is to make a negative with a 3D print and then use it to make a wax positive. I used to work in a casting house and they made their positives with wax. It was specialized of course but you could get really high res parts with it.
That sounds interesting, I think with modern technology the way to make super detailed parts is to make a positive using a resin 3d printer.
Awesome video as usual, can't wait for the next one.
Thank you very much.
Great video! There is A LOT of work behind this video, I'm dreaming of similiar project but I am still in the CAD phase :)
Maybe try to increase temperature a bit or more head pressure?
If it is too time consuming to print a complete head for testing and the downscaled version might have to fine details you could try with a slice of the full size head? Best of luck!
Thanks man, yep the hours are adding up that's for sure. Mold temp was definitely not as hot as it should have been. The alu itself was pretty close to max temp for mechanical properties.
Main reason for doing scalded down ones first was much less cost per casting so I can get more attempts at practicing.😁
Suggest more head pressure behind feeding the aluminium. Vaccum added and hotter melt would nail it.
Yep that's currently the plan, thanks for the input.
Great video.
Would love some more details, longer videos would be nice!
OK awesome to hear and good to know.
I'll make the next one a bit longer and keep in more of the details!
thats frikkin cool as hell
Thanks man!
ive heard some bad things about casting and pouring hot metals on concrete, esp as the temperatures go up, if there is a spill it can cause the water in the concrete to explode sending liquid hot metal everywhere
Yep read that as well, hence the heated steel plate I'm pouring on to mitigate most of that potential problem.😬
How about using a funnel to increase the graviational feed of the molten aluminium?
Yep I have a taller and wider sprue for the next attempt
You're attempting to directly cast from the pour sprue, and that's a headache.
First thing first. You're inlet sprue is too small, and your outlet sprue is extremely undersized.
What you want to do, is have the same size inlet and outlet sprue risers. these need to be significantly sized, as they allow fast filling of the cavity, and allows the metal to pull excess material from them so shrinkage happens mostly in the risers, and not in the casting itself. (sunken in surfaces on a casting are a pain)
You also want to separate your fill sprue, from your casting. using a series of "runners" and "gates" is the best method, as it allows the metal to flow into the part from multiple directions. This will help eliminate cold shuts (the metal freezing before the mold is completely filled)
Create a ring around your part, that is roughly 1/2 the diameter of your fill sprue, this is the "runner".
smaller 1/4 diameter "gates" connect the "runner" to the part on at least 2 sides (more if you can fit it)
On the top of your part, you'll have the "riser" this serves as a "well" of molten metal the part can pull from when cooling.
Any points that are prone to trapping air, you want to put small "risers" these will let the air escape, and serve as little miniature wells.
I cannot thank you enough for this info, a lot of the info on the next wasn't very clear.
I will definitely be using these tips in the next casting attempts.
Molde foi feito de que
a small part that like, it is much better to do a LOST WAX or lost FOAM method with a silica sand slurry mold. you MUST preheat that sand casting, you need a lot more information but over all, much better than i would expect from a 1st time attempt with no real experience with those small parts. i did a LOT of DIY casting for RC parts and once i started doing lost wax in a silica slurry mold, things DRASTICALLY went better and faster.
OK thank you for the information Timothy, I will look into that right away.
How easy would it be to remove that style of mold from the insides of the casting like the water jacket?
@@TheMotorcycleForge The aluminum just takes the place of the wax, you can put in a core out of CO2 activated sand. the issue is the amount of work to get it finished, sand in and on the surface layer is impossible to machine or sand down or file. a silica slury mold is the key here, the wax is just faster, or if you have a 3d printer go with a PLA and bake out the contents then pour the aluminum. you will need a furnace for that though.
OK good to know, I'm currently using 3d printer and burning the pla out to get a mold in the investment.
Need to improve gating system for sure and better heat management.
@@TheMotorcycleForge I think a lot of the issue you might have there is a little moisture in that sand, next time pop that mold int he oven for 15 minutes at 500. might make a difference? its a small pour, still, keep up the good work and content
Thanks man, will do.
John Britten much?
He my Hero and a huge inspiration for sure 😁