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Well, a few threads back, a fellow said no poly over epoxy, question, I was going to epoxy primer whole car after stripping old paint, then do finishing putty over flaws and minor imperfections , is this correct? or
should I do finishing putty first, then epoxy printer then basecoat/clear. Thanks
p.s. i DID MY 58 A FEW YEARS AGO and after a few months I could see imperfections if the sun/shade was just rite, what did I do wrong?
I would use 2K primer surfacer over the epoxy, block it, use the putty for missed imperfections, reprime and block, seal is all up with epoxy primer sealer and go from there.
Could maybe expand a little more like what year car, a few pictures. I would think you would want to be working on raw fiberglass and getting all of your work done first. I would recommend VPA for certain work and then a polyester primer. Never used putty, but to each his own.
Ive never had problems with polyester fillers over epoxy. If youre spraying highbuild i do it within the recoat time or sand back the entire car. ive skim coated areas with cured sealer after scratching/breaking thru the surface with 80-120 even up to 180 without breakthru for glaze putty. and finish with another coat of sealer.
Nothing has ever cracked off, no delaminated paint, no bleedthru, no fisheye, nothing has melted off, sponatneously combusted or exploded. Im sure that mechanical adhesion of whatever is not as strong as fresh epoxy chemical bond. Ive sealed cars with epoxy and thrown in storage for over a year too. I live in sunny(hot as hell) california, Idk if that makes a difference (no snow/freezing) but all is good.
I understand the science and the data sheets that say its better, but in real normal life situations ive never had problems(im not kicking my body panels regularly. not taking a paintscraper to the surface, i dont rip off duct tape to check for adhesion, etc)
the reason you have problem spots is probably shrinkback from the materials you are using. I skim glaze putty and cure as long as possible and work on other areas. then come back with final sand and seal.
Yes, shrinkback is my problem, I think I may wait a good month or so after 2nd epoxy, sand with 600 wet and send to paint, thanks for all your input guys. Mike.
I made my own filler by using West Systems epoxy and their number 10 Fairing Filler. You mix the epoxy according to directions (4 to 1) and then begin to add the fairing filler (It is a dusty pink fibrous material) until you get to the consistency of peanut butter. Then apply over minor imperfections, just like finishing putty. It adheres well and sands easily to a smooth finish. West Systems epoxy is stable when cured and adheres strongly to almost anything
Yes, shrinkback is my problem, I think I may wait a good month or so after 2nd epoxy, sand with 600 wet and send to paint, thanks for all your input guys. Mike.
Obviously you can do as you wish due to time is not a concern for you.
DEPENDING on the manufacture of the epoxy primer. Some epoxies are really not good to stack and get thick,,,,while others are. Or at least that is what I have heard due to I do not use epoxies that I need to stack layer upon layer of to get build. I use a high build primer on top of the epoxy primer.
Not knowing what year you are working on ...for me...changes what I put on the body first. but that is just me and how I do it.
As the choice of what to fill any imperfections in with...I have my views on this and I would use Vette Panel Adhesive correctly do not think twice about it.....REGARDLESS if it is a 1953 or a 2018.
Well, a few threads back, a fellow said no poly over epoxy, question, I was going to epoxy primer whole car after stripping old paint, then do finishing putty over flaws and minor imperfections , is this correct? or
should I do finishing putty first, then epoxy printer then basecoat/clear. Thanks
p.s. i DID MY 58 A FEW YEARS AGO and after a few months I could see imperfections if the sun/shade was just rite, what did I do wrong?
polyester shrink a lot more than epoxys, but epoxys take a lot more time to cure unless forced to. If I have big repairs in my parts, I will use some cheap black paint, spray them and bake it in the Florida sun for a few weeks, this way it will shrink as much as possible before sanding it this way there are no surprises.
At the body shop last winter where I was working on my C10 project they used a 2 part spot type putty. Mixes just like regular body filler. The body guy said never use that spot putty stuff that you buy at the chain auto stores. He said it doesn't adhere properly and shrinks too much. The other thing they did to fill minor imperfections pin holes and such was mix the spot putty with regular filler 1:1. It sanded like butter. Then the high build primer. We did epoxy primer first to keep the bare steel from rusting. Then skim coated everything in body filler and sanded 95% of that off. Then a coat of "poly" filler sanded 95% of that off. Then two rounds of high build primer. First with 180 grit and the second with 320 grit. Each stage was block sanded by hand. The body guy said I didn't have the skills to use power tools.
Not all polyester fillers are the same... so saying if someone feels that they all shrink is not necessarily true. I use polyester primer and I can tell you that it does not shrink. The polyester gelcoat I use does not shrink.
And if any of the products I use do shrink.... they are so slight that it is not a concern.
Well, a few threads back, a fellow said no poly over epoxy, question, I was going to epoxy primer whole car after stripping old paint, then do finishing putty over flaws and minor imperfections , is this correct? or
should I do finishing putty first, then epoxy printer then basecoat/clear. Thanks
p.s. i DID MY 58 A FEW YEARS AGO and after a few months I could see imperfections if the sun/shade was just rite, what did I do wrong?
what kind of putty/filler did you use on the imperfections that showed up a few months later?
In Canada I use 'bondo light', not sure if it is sold in U.S., I have never used gelcoat, the front end I used on the 58 was 'aftermarket' and full of waves, used lost of bondo, then finishing putty, I thought, or my 'error' was too much
putty on some spots 1/4 in thick to fix the darn waves on the front clip, when I bought car it came with it, not sure who made it but it sure was a piece of junk, next time I will try to find a real clip to put on. I'm an old fart that used
to work in a body shop 40 years ago and gel coat never came up then, just a lack of knowledge.
Honestly... if the integrity of the panel itself is solid ....That is good. So if you press on the panel and it moves really easy. I have to wonder. They may have made it as cheap as possible and did not put enough layers on it to give it strength especial in the large flat areas. Kind of like the steel panels on some import cars today...the metal is so thin you just about can not hammer and dollie it out due to you can buy a new fender cheaper than it is to slap filler on it....compared to a fender for a 1962 Cadillac. Knowing you have been doing bodywork as long as you have you know the curves in your body panel provide strength and rigidity to that area. So if you can press on the curve in the front end and it moves...that should be letting you know you basically have a part that is thin as all get out.
I can say the body filler you used is not what I would use due to it is just like it is called.... 'lite;.
I can say that I have repaired numerous aftermarket panels that are not the best in the world and use EVERCOAT's Vette Panel Adhesive/Filler on them and it works. I know you know how to do body work but this Vette Panel Adhesive is in a world all its own in comparison to the 'lite' body fillers of today. It mixes adn spread the same but it gets really hard so getting in on it while it is in that state that cheese grater can be used is often time the best if your spreading skills are like that of someone doing stucco work. I know you can spread filler with the best of them...just letting you know that this is great stuff and it feathers out like a dream. If you need to know more...PM me.
And if you choose to use a gelcoat,...get one that is isophthalic based. Which is what I use and is explained in the last paragraph in the TRADITIONAL SYSTEMS portion of the link provided below. I have used it on Corevettes that I feel need it a for decades and not ONE problem at all.
The waves in the part you have sound of been cause by a number of things, a couple being the builder pulling the part too soon and it finishing it’s cure outside of the mold, or they did not use a tooling resin to build the mold, and mold changing shape many parts later from being heated up so much. Water under the bridge now.
Dub I would love to see some tests with that vpa as far as shrinking, I don’t doubt it, but that is a lot for a manufacturer to say it doesn’t shrink. Maybe a cup of it weighed out before it kicks and a couple weeks out in the sun and reweighed?
i agree with you on the isophthalic gelcoats, I have sprayed over 100 boats with isophtalic gelcoat. Hk gelcoats to be exact. Compared to ortho. Gelcoats they don’t shrink as much, are superior in water resistance, and have higher heat tolerance.
some might say, well it’s a corvette not a boat so water resistance isn’t a concern. Let’s say someone gelcoats their corvette and it sits outside under a cover for years. Maybe a puddle sits on it for some time. I would trust the isophalic over cheap ortho gelcoats any day.
When you leave your left over gelcoat that you did not use in the mixing bucket and it cured up solid....and a day, week or month later you go over and it is still solid against the walls of the mixing bucket and you have to 'pop' it out of it....because the gelcoat did not draw up about 1/4" all the way around the bucket. ..and just fall out....SO you basically know it does not shrink to any serious magnitude.....right?
Well VPA is no different than polyester resin, polyester gelcoat ...polyester primer. When it cures up it is ROCK SOLID and cannot be compared top any of the major body fillers out on the market for its capabilities and that it can do.
And for what it is worth...and I know you were using it for an example....but never suggest that someone covers their Corvette outside for years. car covers are very dangerous to a Corvettes body IF they are not maintained. And I do not care if they say it is for outside use. Corvettes that are covered outside and neglected and the cover not removed after rainstorms and such are just asking for paint problems and also interior mold, mildew and rust and also. electrical issues.
finishing putty(exopy/poly)
