Paint bubble
 

I moved the corvette out of the garage today for a thorough garage cleaning. It was a nice 86°F with hardly a cloud in the sky. This is what awaited me after about 7 hours in the sun. :ack:

http://i187.photobucket.com/albums/x...ntBubble-1.jpg

It is about half way down the drivers side on the fender. At this point, I want to mitigate the problem and prevent it from getting bigger. The car was repainted in 2006, but has lived in a climate-controlled garage until I purchased it about a year ago. I don't know if it has ever sat in the sun for that length of time.

Suggestions?

Have a seat. This is likely only the first of more bubbles to come as the car gets exposed to the elements. There are several reasons it might be bubbling; all of them require diagnosis and complete pant removal to cure permanently.

You may be extremely fortunate and have only this one area fight back against whatever contamination is below the paint in which case my advice would be to live with it for now... let us know if more areas fail as the car gets used some. Good luck.

Funny thing about fiberglass things sneak in from below sometimes. I have seen oil from the A/C units do this to hoods and oil from a tar like under coatings do this to the top of the surrounds right above the tires. Heat from the sun can draw it up.

Similar problem with mine...getting worse. My problem started around the taillights. The paint is getting to the point of lettting go. I have a big piece ready to flake off. Expensive to fix. I believe heat is a big contributor. My problem was caused by the garage door being up and sun shining on the back end of the car and heating up the fiberglass. The problem probably happens more with dark color vettes.

I feel your pain.

My black 79 has several of these spots, and I've heard before thats its because of something getting on the fiberglass (bare, I guess??)
LeMans, I wouldn't worry too much, yours is still one of the sexiest I've seen, ;) Love that color!

I have a similar problem on my 72. One area is at the top of the T Bar roof, and the other is on the right rear fender area. I am so tempted to pop it, or stick a needle in it, but then I thought it would only cause it to get worse. So I am living with it for now.

Nothing quite as large as the quarter size you are showing, but they are there nonetheless, and I dont know what to do about it other than live with it for now.

kdf

The fiberglass is 'out-gassing' because of some volatile comtaminant left on the surface or from some repair compound used below the paint; or it could be from some petroleum-based substance that bled through the fiberglass from below (like the A/C refrigerant/oil suggested above). I have them on my hood just above the front A/C compressor seal--obviously some failure of that system with the prior owner who had it repainted some years ago.

I think we all hope this instance is isolated.

How do you prevent this from happening? Eventually I will want mine repainted and wondered if there is something they can clean it or treat it with before the paint goes on?

Make a photographic record of known trouble areas and look carefully for a cause after paint removal. Remember that fiberglass is both porous and permeable... things like A/C oil, undercoating, tire shine sling-off and silicone brake fluid drips can seep through the glass from below.

Also as you strip, pop the bubbles and lift the paint to see if you can smell trapped solvents in the area, or if there is liquid in the bubble which you might ID. If a painter applies too much film build without waiting for adequate dry time, those trapped solvents can "pop" the paint off if the car gets warm enough to evaporate them.

Fixing solvent pop is straightforward... remove everything and repaint using correct technique.

Cleaning contaminated panels is complex and time consuming... and the technique is somewhat dependent on the contaminant. Plain old Dawn dish soap and water applied both sides repeatedly is a pretty good way to start...just be certain you rinse well and allow adequate dry time before sealer.

Prick them with a needle. Find out what's in them...just air or maybe some kind of fluid. Then slice with a new single edge razor blade. Flatten down with a squeegee. Doing this while it's warm out is best. The longer you wait, the more stretched the topcoat will get. Good luck.

Cars without AC too. My '67 was painted about 1990 and :ack:"leaching" on top of the drivers side fender started about 8 years ago. Looked like a bad case of acne. Read that it is fairly common with the way the vapors travel underneath the hood - then consider the wicking effect of a car thats been heat cycled for over 40 years.

:willy: I'd just leave it - otherwise you'll end up stripping the whole thing and doing a repaint - and maybe have the same thing happen again. Just my .02 fwiw.

For anyone doing a repaint, I would think that the underside of the hood should be painted with some kind of sealer or epoxy paint which would prevent engine compartment contamination from making contact with the hood fiberglass.

I've read (FWIW) that the way to do it, is to take the finish down to the bare glass (and I wouldn't use chemical stripper), repeat wiping it down with acetone until contaminates leach less (it will take repeated wiping and you'll never get it to completly stop), gelcoat etc. to a completed paint job. I was told (again, FWIW) NOT to paint the underside (whether hood or fender top) so that the contaminates can now go (after the gelcoat) the other way out. They need to be able to get out someway. This is the procedure I'm using on my '67 but I won't be able to give results till next year. I thought I had my leaching stopped coming out from the top of the front fender but the $hit still comes out after a hot ride. But I still keep wiping down with acetone and maybe when I get around to finishing it, it'll stop - I keep hoping.

What gelcoat?

:iagree: I used SPI epoxy :thumbs:

Thanks for the replies. These paint bubbles are obviously frustrating for many. At this point I have no plans to repaint the entire car due to this blemish.

This is what I'm looking for. Since I believe the heat brought this about, its probably something volatile that has been released under the paint. Is pricking this a good idea? I can see it becoming a wrinkly mess quickly. I agree with the process, but I think I could make it look ALOT worse than a bubble.

My fear is that since it was only 86°F and sunny, a good 95°F and sunny will only make this bubble bigger.

Most likely gassing out.. The hot sun doesn't help.. Sometimes it corrects itself.. What I have done with other cars is put a tiny slit in it with a razor... Let it release in the sun for a few hrs.. Pref a few days.. Then seal it with a drop of clear... Fiberglass loves to gas out in the heat..had one the size is a basketball develop while baking the car...after it cooled it never returned..

You will find when it goes back in the shade it will shrink some. I also have had these on other cars. I would give it 6 months and leaving it in the sun every now and again. If no more bubbles arise I would not take any chances to just sand and repaint that section, Cut it out completely and reglass that section cause whatever is in that section will leach out forever even with heat lamps.

Had a similar looking problem with my 81 hood at the front.After 2 refinishing jobs on the hood we discovered water was trapped in the hood.Drilled drain holes at the lowest point of hood on the underside problem solved.