docent

Any suggestions? ? After posting about a month ago, regarding bubbles in the paint, under my hood, - - and ordering a couple cans of that Industrial Krylon Semi Gloss Paint as suggested, those bubbles are coming back.
I sanded the underside of my hood, off the car, very carefully, and repainted with the Krylon paint (I had to order the paint off the Internet) It looked good ! But its been a couple weeks, and a few drives around town, and bubbles under the paint are starting to come back. My car doesn't run hot. Its stays around 180 all the time. When I return home, and park it in the garage, I lift the hood to let the engine cool quicker. Should I take the hood off, and have it "soda-blasted?" Then try painting it again? I thought the hand sanding would do, but apparently NOT. Any suggestions?

Frankie the Fink

I'm no body/paint guy but from reading about what others have had to do to eliminate contaminants from the underside of the hood when air conditioning compressors leaked freon/oil onto the fiberglass, I'm betting you have a similar problem. Some bit of nastiness has worked its way into your fiberglass. Others here may have some help to offer or you can PM forum member DUB - a savvy body/paint man.

Some procedures I've read about involve grinding and back-filling and/or soaking the affected area with something to draw out the contaminants.

Mike Geary

My suggestion would be to sand off the Krylon and leave the surface bare for several months. Give the contaminant a lot of time to migrate to the surface. Wipe downs with acetone will help the process.

If you prematurely seal the inside surface, the nasty stuff might decide to come out on the hood's exterior.

Any idea what the contaminant is? Compressor oil? PS fluid?

docent

I don't know if "contaminants" is the answer. I don't have AC, PS fluid, Compressor oil, etc. There were a few bubbles, when I bought the car,and that was it. It looked dry. Forum suggested to sand the underside of the hood lightly, and repaint with Industrial Krylon Semi Black spray paint. That's what I did a couple weeks ago, and now the bubbles, (about the size of quarters) are coming back. But, the recommendation of taking it to a body shop, is something I probably do. Maybe they might have some suggestions.

65silververt

All it takes is a nice spray of brake fluid. oil hitting the hood, or say armor all used around the hood when it was in bare glass to cause issues later on. The problem is that you need to remove the hood, strip it, then let it sit outside in the sun to bake out the contaminants. I would use a high quality epoxy primer(have a shop spray it if you dont have a gun) before applying krylon or some other rattle can paint.

65 Pro Vette

Are you sure it is an original hood? Corvette image was selling junk fiberglass for years with silicone in the glass, paint blisters all the time.

rtruman

Krylon is real easy to work with sand it smooth and do it again only the areas that lifted
I do mine all the time every year whether it needs it or not . It it lifts in the same areas again then go to body shop . Before I painted mine I rubbed it with lacquer thinner ,
be careful around fenders and paint.

Vette Daddy

Soda blast
Wash surface with lacquer thinner and also degreaser
Let the sun bake the surface if possible, repeatedly
SEAL and let set in the sun for long periods
Paint Krylon "dry". Do not lay it on heavy.

docent

I'm going to try it again, but this time, after I sand the areas, wipe it down with lacquer thinner, and see if that helps bond the paint. I will leave it out in the sun for a few hours afterwards, before installing it back on the car. At a car show yesterday, I saw an old Chevy Nova, that had the insulate/noise pads, under the hood. It was clean, and you didn't see any bubbles with those installed.

ricks327

No expert here but I would let it sit in the sun for a few days (the longer the better) rather than a few hours. Take advantage of that Calif. sun image.
Rick

rtruman

Make sure you put a towel on air cleaner while in sun it could burn hole in the underside of hood.

docent

Thank you, your absolutely RIGHT. I do get reflection from my air cleaner at the car shows, when I have my hood up.

MarvBarrish

I had this problem with 2 hoods for my 66. I gave up on the first hood and bought a second hood to only have the same problem. So I went to plan B. I ended up using pick up bed liner spray. I found one that was a semi gloss black and thinned it with acetone by over 50% and then sprayed it on the underside of the hood. It came out very nice! Very smooth and it sticks like glue. No more bubbling. This might qualify as a bubba fix but I'm just a working man and can't afford to keep throwing money at a stupid problem.

Jimbo64

i agree-very, very important to cover air cleaner or reflective parts if you have them-some have a lot of chrome under there that can reflect the sun and do a lot of damage- good luck

C2Racer

A lot of chemicals will cause this. Lithium grease, WD-40, Armor-all..... and lacquer thinner has not worked for me. I would either have it soda blasted or seal it with something like MarvBarrish did. Blasting it is the best solution but if it's in the fiberglass deep a sealer may end up being the only solution. I would guess that the original factory paint if still there protected the fiberglass from it? POR 15 has a black that may work on fiberglass but try a piece not on the car first. Don't bother calling them as they don't even understand their own labels. Just need to keep experimenting. Good luck!

Steve

rtruman

I just got paint done first car show this June a judge picked up my hood the towel blew off and there it was 4 inch line burned on under
side of hood ,blistered top of hood .
I bought the cover that doesn't blow off. A lot of midyear people really didn't know this problem.