This is a very good explanation and really great advice. When I was doing collision repair, it was standard practice to apply filler directly to bare metal to save both time and money. However, every time a repair would get into an area that had filler applied from a previous repair I would always find some type of corrosion between the filler and metal and the filler could often be popped off. As a result of this, once I opened my own shop doing restoration work, I started spraying epoxy after doing metal work but before applying filler. The cost of two coats of epoxy is nothing compared to the cost of your reputation when you have to warranty a repair for bubbling/blistering.
I understand what's being explained here but there are so many variables in body and paint and different techniques. Like what condition that bare metal on that Dodge was in before the body work was even started. We don't know. The filler could have been applied over sanded rust like some amateurs do. So was it really the filler reaction or poor prep? Like people online bashing polyester primer adhesion not realizing years ago it was only designed for small areas of bare metal not whole bare panels. I did a collision repair on my own car with filler over metal. Daily driver in road salt put over 200k and the filler never popped. Point is, the epoxy is a fail safe but there are a lot of different situations out there that no one will ever know what was done. Some of these restorations were done years ago before better products and techniques.
Agreed... years ago repair shops used filler over bare metal all the time.....I've removed 40 year old repairs over bare metal and even over un- catalyzed paint that was still in good condition ...
Explaining it perfectly. I've been in the body shop biz 32+years and been around it over 35 years. Everyone out there was taught to plastic over bare metal. Guys that have been doing this type of work from way back when, cannot grasp the idea of not putting plastic work directly over bare metal. Hard to teach an old dog new tricks. This channel if great. Keep it coming. Is nice to see a real professional approach to this type of work.
I entirely agree with you on this and use filler over epoxy these days. But... back in the day I did use it straight over clean prepped metal and I've still got a car I restored in '89 (35 years ago!) that still hasn't suffered filler failure anywhere to date, so the old school method doesn't always fail!
So many shops go to bare metal and start body work. I'm a newb and know better . Why take a chance? Again this channel continues to give quality videos. Ty!
I am sure its a great thing to do ...and this technician has been taught this from the begining ....but 20 years ago when i worked in an auto body repair shop ....it was very common to put filler on bare metal ....and then y2k urathane primer over the repair ....usually several coats so it could be blocked to profection ....then after all the pre prep before paint ....would use a color specific tinted sealer to lock it all down ....all body work comes down to prep ....better the surface is prepped better results you will achieve....i did a 94 s10 frame off and did several areas of bare metal filler ....and it still looks amazing to this day ....i dont own it anymore but paint and body work still looks amazing on the truck.....but i am sure the epoxy has its benifits .....but you can use filler on bare metal
Great explanation, WAY back in “the day” we did collision repair we would use fiberglass “kitty hair” over bare metal when we would have done a metal patch repair, then primer and finish with body filler as needed
Good explanation. Unfortunately it’s never going to happen in the collision world. Fortunately quality guys know better. We’ve had an epoxy based body filler in testing for years now. It’s actually an aircraft spec coating. It has phenomenal adhesion, zero shrinkage, very tough, and has give to it. And because it’s epoxy, it’s 100% acceptable to put directly to metal. It takes 8 hours to cure, but worth it completely.
I agree with this guy, filler onto bare metal starts rusting because of the acid in product doesn’t matter how clean the surface is it starts the rusting process.
it's crazy i just watched D.I.Y Auto schools channel and his saying totally the opposite thing (maybe a bit old school in his way of thinking?) however I'm with you on this one epoxy is there to seal up metal then once sealed you work on top of that and to me that makes far more sense.. I'm even going epoxy, body filler, epoxy over the body filler and then final paint might be over kill but in the 40 series Landcruiser world most people seem to go this route
Is it safe to put my high build right over my epoxy? I’m locking down my filler and exposed metal from sanding with another coat of epoxy and would wait about 2 hrs and then stack 3 coats of high build. My tds sheet says I can do this but like to hear from some of the best. Just trying to save myself more sanding if possible. I’m just worried about possible solvent trap or do you think it should be ok. After high build is sprayed my cab will sit for a good month or so before I go back to blocking to make sure everything has shrunk and off gassed.
I always thought what a bs idea to put something else than rust inhibiter on pure metal? I use, cause epoxy stuff is very expensive in brasil, a paint or primer that´s made to go over rust. I clean and treat chemical before, but I use this direct on rust stuff, then i go with filler. I´m not a pro, but I did on my first job what "everybody" told to do, and it went wrong. today I go my way and it works better,
My hat is off to you my friend. It's surprising how many so called "tech's" don't know this and don't care! It's just unfortunate that by the time this becomes standard practice the amount of vehicles made will barely have any metal in them😂😁
Kitty hair is a polyester product like all fillers. It’s no exception. Always epoxy first. Sense we’re hear, I’ll recommend Fibertech. It’s tough as nails and was our go-to for years before our switch to Epoxy filler. Kitty Hair should have been discontinued 40 years ago.
You should be able to epoxy over filler and technically get the same results. Either way, you'll be sanding through the epoxy before you put filler over it. So technically, the epoxy will be compromised before you apply filler. As long as you don't leave the metal exposed for to long before you finish bondo and spray epoxy it should give you similar results. I've done both but I prefer directly to metal because the epoxy tends to be brittle and could have adhesion problems after sanding it with 80 to 120 grit. And either way I would epoxy over everything after the filler was finished sanded.
Does bondo Glass suck up water too like regular bondo or is it really waterproof like it advertises? Do you think it will rust also if you put it on bare metal?
Yes I preach this because of watching linear blocks vids, just makes good sense, but the old school guys will rip your head off because they have been doing it for years and it lasts forever 🙄.
If you’re not using a crud thug over your metal on the rust of course filler and epoxy will come off numb nuts. At the end of the day, metal has a way of being prepped period. If you don’t do it right in any area, your epoxy will peel as well.
Body filler on bare metal is a faster way and better way of working old schools because if your metal is not prepped correctly to 80 grit sand paper at minimum, epoxy can peel just like filler. Saying filler shouldn’t go on bare metal is B.S my guy.
This is a very good explanation and really great advice.
When I was doing collision repair, it was standard practice to apply filler directly to bare metal to save both time and money. However, every time a repair would get into an area that had filler applied from a previous repair I would always find some type of corrosion between the filler and metal and the filler could often be popped off.
As a result of this, once I opened my own shop doing restoration work, I started spraying epoxy after doing metal work but before applying filler. The cost of two coats of epoxy is nothing compared to the cost of your reputation when you have to warranty a repair for bubbling/blistering.
I understand what's being explained here but there are so many variables in body and paint and different techniques. Like what condition that bare metal on that Dodge was in before the body work was even started. We don't know. The filler could have been applied over sanded rust like some amateurs do. So was it really the filler reaction or poor prep? Like people online bashing polyester primer adhesion not realizing years ago it was only designed for small areas of bare metal not whole bare panels. I did a collision repair on my own car with filler over metal. Daily driver in road salt put over 200k and the filler never popped. Point is, the epoxy is a fail safe but there are a lot of different situations out there that no one will ever know what was done. Some of these restorations were done years ago before better products and techniques.
Agreed... years ago repair shops used filler over bare metal all the time.....I've removed 40 year old repairs over bare metal and even over un- catalyzed paint that was still in good condition ...
Explaining it perfectly. I've been in the body shop biz 32+years and been around it over 35 years. Everyone out there was taught to plastic over bare metal. Guys that have been doing this type of work from way back when, cannot grasp the idea of not putting plastic work directly over bare metal. Hard to teach an old dog new tricks. This channel if great. Keep it coming. Is nice to see a real professional approach to this type of work.
I entirely agree with you on this and use filler over epoxy these days. But... back in the day I did use it straight over clean prepped metal and I've still got a car I restored in '89 (35 years ago!) that still hasn't suffered filler failure anywhere to date, so the old school method doesn't always fail!
So many shops go to bare metal and start body work. I'm a newb and know better . Why take a chance?
Again this channel continues to give quality videos. Ty!
I am sure its a great thing to do ...and this technician has been taught this from the begining ....but 20 years ago when i worked in an auto body repair shop ....it was very common to put filler on bare metal ....and then y2k urathane primer over the repair ....usually several coats so it could be blocked to profection ....then after all the pre prep before paint ....would use a color specific tinted sealer to lock it all down ....all body work comes down to prep ....better the surface is prepped better results you will achieve....i did a 94 s10 frame off and did several areas of bare metal filler ....and it still looks amazing to this day ....i dont own it anymore but paint and body work still looks amazing on the truck.....but i am sure the epoxy has its benifits .....but you can use filler on bare metal
Great explanation, WAY back in “the day” we did collision repair we would use fiberglass “kitty hair” over bare metal when we would have done a metal patch repair, then primer and finish with body filler as needed
great video very well explained..
100% convinced now. I have never tried filler over bare metal before, and will definitely NOT try it in the future! Great video!
Good explanation. Unfortunately it’s never going to happen in the collision world. Fortunately quality guys know better.
We’ve had an epoxy based body filler in testing for years now. It’s actually an aircraft spec coating. It has phenomenal adhesion, zero shrinkage, very tough, and has give to it. And because it’s epoxy, it’s 100% acceptable to put directly to metal. It takes 8 hours to cure, but worth it completely.
Great video! can you tell me what scale you use for weighing filler? ...the ones I am finding aren't very accurate.
I agree with this guy, filler onto bare metal starts rusting because of the acid in product doesn’t matter how clean the surface is it starts the rusting process.
it's crazy i just watched D.I.Y Auto schools channel and his saying totally the opposite thing (maybe a bit old school in his way of thinking?) however I'm with you on this one epoxy is there to seal up metal then once sealed you work on top of that and to me that makes far more sense.. I'm even going epoxy, body filler, epoxy over the body filler and then final paint might be over kill but in the 40 series Landcruiser world most people seem to go this route
Is it safe to put my high build right over my epoxy? I’m locking down my filler and exposed metal from sanding with another coat of epoxy and would wait about 2 hrs and then stack 3 coats of high build. My tds sheet says I can do this but like to hear from some of the best. Just trying to save myself more sanding if possible. I’m just worried about possible solvent trap or do you think it should be ok. After high build is sprayed my cab will sit for a good month or so before I go back to blocking to make sure everything has shrunk and off gassed.
Spot on well said
what is the brand of your measuring scale?
Do you put another layer of epoxy or sealer again after filler or can you go straight to top coat?
Fiber Glass? does it work?
I have seen rust under filler many times when stripping down to bare metal and it will eventually cause it to flake or break off
I always thought what a bs idea to put something else than rust inhibiter on pure metal? I use, cause epoxy stuff is very expensive in brasil, a paint or primer that´s made to go over rust. I clean and treat chemical before, but I use this direct on rust stuff, then i go with filler. I´m not a pro, but I did on my first job what "everybody" told to do, and it went wrong. today I go my way and it works better,
My hat is off to you my friend. It's surprising how many so called "tech's" don't know this and don't care! It's just unfortunate that by the time this becomes standard practice the amount of vehicles made will barely have any metal in them😂😁
all filler except kitty hair right? Need to apply kitty hair over sail panel welds and tds said just metal. What is your procedure?
Kitty hair is a polyester product like all fillers. It’s no exception. Always epoxy first. Sense we’re hear, I’ll recommend Fibertech. It’s tough as nails and was our go-to for years before our switch to Epoxy filler. Kitty Hair should have been discontinued 40 years ago.
You should be able to epoxy over filler and technically get the same results.
Either way, you'll be sanding through the epoxy before you put filler over it. So technically, the epoxy will be compromised before you apply filler.
As long as you don't leave the metal exposed for to long before you finish bondo and spray epoxy it should give you similar results.
I've done both but I prefer directly to metal because the epoxy tends to be brittle and could have adhesion problems after sanding it with 80 to 120 grit. And either way I would epoxy over everything after the filler was finished sanded.
Does bondo Glass suck up water too like regular bondo or is it really waterproof like it advertises? Do you think it will rust also if you put it on bare metal?
Good videos!
100% agree.
So wonder why you dont use etching primer , first over bare metal , before Urathane primer
No need for etching primer when you use epoxy. Epoxy is actually a step up.
You see it all the time at car shows ….. totally agree with epoxy. Epoxy epoxy epoxy
BINGO !!!
Yes I preach this because of watching linear blocks vids, just makes good sense, but the old school guys will rip your head off because they have been doing it for years and it lasts forever 🙄.
Lol..... So true
Put Mipa onto the bare metal, let that dry, fill over it. Mipa is a corrosion protectant & it's damn good. Mipa ain't breathable.
Epoxy is a link between the metal and polyester
If you’re not using a crud thug over your metal on the rust of course filler and epoxy will come off numb nuts. At the end of the day, metal has a way of being prepped period. If you don’t do it right in any area, your epoxy will peel as well.
Body filler on bare metal is a faster way and better way of working old schools because if your metal is not prepped correctly to 80 grit sand paper at minimum, epoxy can peel just like filler. Saying filler shouldn’t go on bare metal is B.S my guy.