Bubbles Under Paint Again!
 

I had my '61 painted several years ago and after about two years, I noticed bubbles under the paint started to appear. I then took it to a reputable painter who does Corvettes. I had the car completely stripped and repainted again and the paint job came out great. It has been about two years since the last paint. Since it was 80 degrees here in So Cal., I took it out for a spin and noticed that the paint is again starting to bubble under the paint in the same area's ( right fender and front valance).
WTF is going on? Is it something in the fiberglass that decides to emit and bubble after two years or what? I thought I was done with this issue. Body and paint guys please chime in. Thanks :willy:

Brake fluid absorbed in fiberglass..
 

Hello

Sounds like containmented fiberglass (like brake fluid) fiberglass is absorbs thing like that. You have to clean it WELL with acetone or grind old fiberglass out put new stuff in..I have the same thing you have on my driverside fender alot of tiny bubbles..

Good luck
:cheers:

:iagree:

How do you find where the contaminants are once the paint is stripped?

Gelcoat the areas before you paint. The glass has to be sealed. That will hold down the contaminates.

:bigears I have the same issue with my 66. Washed the glass extremely well with acetone, baked out the "wash" and continued for over a week, baking the bare glass in over 100 degree heat. This is just one of the procedures I have used during the three paint jobs I have put on the car in the last 4 years. Problem still returns:banghead: The last time the paint shop tired to seal the glass from the outside and have it breath from the back side. Gel coat, sealer etc. everything looked great for about a year. Best of luck. One day I'll try again.

I had the same problem with my 62 after only a month home being out in the summer sun, and my painter said it was a new (15years ago) filler he tried after gouging and reglassing the bonding strip areas. He had to strip it all again, remove the filler and use a tried and true one. No problems since.
________________________________________ ______

P.S. same thing happened on a Jag Etype and a Cobra at the same shop. He was not a happy guy!

Did you replace any body panels, with new fiberglass pieces made by Corvette Image? I remember stories about problems with press molded fiberglass made by them, maybe 5 to 10 years back. I was told the problem was from a mold release agent that they were using. The way I understand it, it impregnated the fiberglass and then would start coming out 6 months or a year later, causing the paint to lift. I've never used any of their pieces myself, but I know a couple people who experienced this problem, with their fiberglass.

I don't know the origin of the body panel as I have had the car for 20 years.

paint bubbles
 

I have a 66 convertible that was completely stripped to the glass and repainted. After 2 years I got the bubbles on the drivers side front fender. I complained to the body shop and they stripped and repainted the whole front end. Before repainting they let it sit outside in the sun for days. They seem to think that the fender was contaminated by brake fluid. I'm not so sure. I'm seriously hoping that this works.

This is one of the typical problems with glass cars. Any kind of contaminant can be absorbed into the glass and re-surface later. Some are almost impossible to detect and correct. Even with the best sealers, they can bleed back. Leaving the car out in the hot sun will help bring them to the surface but I'm not sure you can eliminate them. I would be hard pressed to give any glass car a guarantee for bubbles if I had a body shop. :eek:

I have been told a couple of different things, 1) that the stripping solution can get into the glass and years later cause paint problems.
2) I have some bubbles around a door lock, someone said that it could have been caused from spaying WD40 into the lock it to will get into the glass causing paint problems.
Not sure if there is any truth to either statement.

You have to think about this. Paint is designed to stick to a clean surface. If it don't stick the problem lies on the surface or inside the glass. My mate has a Cobra that is bubbling around the hood and in certain spots on the car and it was new glass ?
I go to a lot of car shows and see heaps of Corvettes that are N0.1 Cracking everywhere there is a corner N0.2 Bubbles in the paint work. Living in Australia we seem to get the crap cars from the States (cost of shipping and taxes create a bottom end car normally).
I had a to laugh a guy on the NCRS site was having this problem with his car but only in one spot. Tried everything but there must of been something in the glass that kept causing the paint to bubble so he got a hole saw out and drilled a 2 inch hole into the guard LOL. Patched and painted it up and has never looked back.
What can you possibly do to get rid of a chemical problem that slowly leaches from the glass. The bubbling seems to appear on extremely hot days.
I would try to use a real thick gel coat after the bare glass has been cleaned and left to gas off in 100 degrees in the hot sun
for days ! This is a real problem that Corvette hobbyists have. Someone should look into this and solve the problem there is money to be made out of this for the clever guy there is a market out there of bubbling cars ? Stewy

paint bubbles
 

I had the same problem on my 69 Coupe many years ago-around 1980. The car still had the original laquer on it and it was being repainted with Dupont laquer. The painter and I discovered tiny pinholes in the gelcoat behind the rear window. When it was warmed with a heat lamp it would cause small bubbles to appear in the paint. He stripped the paint and primer and shot a very thinned out coat of primer on that area so it would fill up the pin holes instead of laying over the top of them. It never bubbled again as long as I owned it-even in the hot So. Cal. summer sun. I don't know if your car has the same issue but it might be worth investigating. Paul

:iagree:
This is not and uncommon thing..I have seen several Corvettes like this...I would bet the farm... You have brake fluid absorbed into your fiberglass. Alot of acetone will take it out...But you must clean it throughly..let it sit clean it again..Etc..

:cheers:

How was it stripped? The shop that works on mine only uses hand sanding to strip Corvettes in order to prevent paint problems. Chemical strippers can cause problems.

If I had that problem I would wash the area several times with both a solvent and a waterbased soap. Then sand the area lightly. Then I would apply two coats of a two component epoxy barrier coating.

Gel coats are designed as a top coat. They contain wax which forms a film on the surface which allows the polyester to crosslink. If you plan to gel coat you must remove the wax layer very carefully or you will have adhesion problems. Epoxies on the other hand are very easy to coat and provide a much better barrier to solvents, gases and just about everything.

Contamination is exactly what's happening here, but you can't get it out with acetone. Acetone will clean the surface and make the surface ready for more contamination to leach through from the bottom layers of fiberglass, which are wet with contaminants from the bottom surface of the fiberglass, i.e. engine oil, brake fluid, armour-all, wd-40 and all the other chemicals we use in our cars. Once the surface is cleaned with acetone, spray gelcoat will form a successful barrier against the contamination IF done properly. The gelcoat has to be substantial - around 3-5 coats of it AFTER sanding. This means you go around the car 5-7 times with gelcoat, then guidecoat it. Spray 2 extra coats in the problem areas. The guidecoat is the key to knowing when you've sanded enough off the top without sanding more than you have to.

I've seen and corrected many oil-impregnated panels, and you don't have to replace them. You just need to seal them.

For people who don't know what a guide coat is it's normally a matt black can of spray that you spray on very lightly so when sanding the panel smoothly if there is any black left you normally have a low spot that needs a feather fill or sand more in that area to bring the panel even with high's and low's ! Panel shops have black dust that they wipe on with a sponge now and it leaves a chalky black dust on the panel which works very good. Stewy

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