Bubbling paint on my hood?

[72Blazerod]

My 1972 Stingray (350 cid w/ 200 horses, not a big block) was painted back in the late 80's. It looks quite nice but the paint seems to be bubbling on my hood. I see the underside of the hood is painted black (which sucks up the heat) which cannot be helping. Has anyone else had this problem? I guess I am going to have to have the hood repainted, but how can I stop it next time (and still have it look stock)? Thanks.

Rod

 

[Alan76]

Paint bubbles

I have the same Problem on my 1973 and my and 1976. My guess is the heat of the engine. On my 76 previous owner had cut the isulation back anf the bubbles are where the A.C. compressor is close to the hood. I replaced the Insulation and solved the problem. On the 1973 the bubble is close to opening in the insulation for the breather, so I haven't figured that out yet. I have also read where theory that oil works its way through the fiberglass and rasies the paint.
But if the under side is also painted I don't see this being vaild. hope this helps.

Alan

 

[72Blazerod]

So do you have a layer of insulation (like the silver heat barrier insulation) on the underside of the hood? My car seems to only have black paint on the underside of its hood.

Rod

 

[Alan76]

Insulation

You can Buy the pre-cut insulation from Corvette Central 1-800-345-4122
you should have 8 or so metal pins glued to the underside of the hood these
use metal retainers that hold the insulation in place these sholud be available
also If the pins are available at Corvette Central , Voluteer Vette in Knoxville Tenn Has them thata wher I got Mine 865 521 9100 they have the Insulation as well
Alan

 

[Eric]

The paint bubbles are usually caused by one of two things and I'll explain both.

1 - Moisture trapped under a cover - As the temperature fluctuates the water can heat up under a cover and vaporize and seep (for lack of a better term) under the paint. Once the car is uncovered the trapped moisture will heat up under the sun and start bubbling up as the air escapes, usually around lowpoints and body seams but this can occur anywhere. If your paint guy is really good it can be repaired, if he isn't absolutely certain he can fix it don't let him touch it because you can end up with a polka dot Vette. All covers claim to prevent this damage but even the best cover should be removed every couple months on a clear day just to air out the paint and seals. If you get a lot of rain or humidity, you should do it even more often.

2 - Oil/grease in the fiberglass - This is a problem unique to fiberglass cars. If your car was ever stripped and repainted or ever had any body work done, grease or oil may be trapped in the glass. This doesn't mean anyone spilled it but rather something as simple as a greasy fingerprint could have ben left on the car prior to painting. If the grease isn't removed immediately it will seep into the glass and the only solution is to cut out that section of glass and replace because there is no way to get the oil out. Even if you strip the glass and scrub it clean the oil is still there below the surface and will always seep. I've actually seen these oil bubbles in the pattern of a handprint around the back of a hood. I don't know the details but this is also common around the A/C unit. And as for the painted hood underside - oil can penetrate most paints over time.

The only way to know which it is is to cut a bubble out. I've never done this myself and would let a pro do it. If the bubble is only a couple of layers of paint, it's probably moisture vapor damage. If you see fiberglass it could be oil, you then have to test the surface. If it feels oily your through, if it doesn't, spray a mist on it and let sit for a minute to see if the oil bubbles out then feel it again. Oil damage can NOT be fixed without replacing fiberglass. If the bubbles are few, and you fix the cause you're probably best to leave them be and pray you don't get more.

Good Luck!

 

[yellow77]

I dont know if this is relevant, but a friend of mine with a 64 vette also had tiny blisters/ almost looked like solvent pops in the hood paint right above the air conditioning compressor front seal, and he said it was a reaction to the freon caused by a slight leak in the front seal of the compressor.


Cheers

Richard

 

[TWINRAY]

I posted about a year ago my problem with both of my Corvettes especially the '67. On both, but the '67 is much worse, I have tiny bubbles on the drivers side top front fender. On the '67, it extends to the cowl behind the hood. I got so annoyed with the looks of the bubbles on the '67, I sanded them off. An oily type substance oozes from the popped zit. This particular vehicle was in primer (in storage) from '76 to '89. I painted it in '89 with Acrylic Lacquer. It was put back on the road in '89. The bubbles appeared in about '00. One theory that I heard was since it was coming on the side of the Master Cylinder, that it could be vapors from the silicone brake fluid. I thought this strange since I thought the regular brake fluid was more caustic (it would remove paint if you spilled it) than silicone.