paint blister
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paint blister
Hello I have a 1974 vette it has a new 3 stage paint job, on the engine hood there is a 3 to 4 inch blister in the paint, when I bought the car 3 months ago I had the seller repaint the hood it came out perfect, but the same blister is just starting to reappear, and I just noticed the inside of hood is missing the insulator blanket that goes on the inside of hood ???? could the engine heat be causing the blister? what do you all think. I have ordered a new insulator blanket, thanks in advance for all input. Rich outttt.
Melting Slicks
Joined: Jul 2009
Posts: 3,264
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From: Vero Beach FL
The cause could be from contaminants coming up from under the hood. Does your car have a/c? Sometimes oil from the a/c compressor will come up from underneath the hood. It does not have to be oil from the a/c compressor that just seems to be one of the more prominent causes.
Team Owner
Joined: Jun 2000
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From: Southbound
Cruise-In II Veteran
Normal underhood temperatures do not get high enough to blister paint from the underside. Corvette hood insulation is for sound deadening purposes, not heat protection.
AC clutch oil can seep through fiberglass over time. Is your paint blister over the AC compressor?
My first hunch is that something is in the fiberglass/primer/sealer causing the top coat to lift.
AC clutch oil can seep through fiberglass over time. Is your paint blister over the AC compressor?
My first hunch is that something is in the fiberglass/primer/sealer causing the top coat to lift.
Melting Slicks
Joined: Jul 2009
Posts: 3,264
Likes: 3
From: Vero Beach FL
Normal underhood temperatures do not get high enough to blister paint from the underside. Corvette hood insulation is for sound deadening purposes, not heat protection.
AC clutch oil can seep through fiberglass over time. Is your paint blister over the AC compressor?
My first hunch is that something is in the fiberglass/primer/sealer causing the top coat to lift.
AC clutch oil can seep through fiberglass over time. Is your paint blister over the AC compressor?
My first hunch is that something is in the fiberglass/primer/sealer causing the top coat to lift.
The bad news there is nothing (that I know of) that will stop it. The hood may need replacing.
Safety Car
Joined: Mar 2007
Posts: 3,652
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From: Bridgewater nj
I have a bubble from heat too. It only happens when I leave it in the sun on a hot day 90+ then it disappears when it cools off. I think moister gets under the gel coat and expanse when it gets hot...
Last edited by hugie82; Aug 22, 2012 at 12:34 PM.
Thread Starter
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Joined: Mar 2012
Posts: 60
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Paint blister
The cause could be from contaminants coming up from under the hood. Does your car have a/c? Sometimes oil from the a/c compressor will come up from underneath the hood. It does not have to be oil from the a/c compressor that just seems to be one of the more prominent causes.
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Melting Slicks
Joined: Jul 2009
Posts: 3,264
Likes: 3
From: Vero Beach FL
You might be able to see oil on the inside of the hood or it could have been cleaned off. I have seen contaminates come from tar based sound deadener the oil from the tar gets in the glass. Fiberglass is porous and absorbs things sort of like a sponge. Once in the glass its difficult if not impossible to get out of the fiberglass if it has started from underneath and worked its way to the top. Setting in the sun draws the contaminates to the surface. This is one of the reason many of us use epoxy primers to help seal the surface before painting. Where on the hood is the paint bubbling?
Thread Starter
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Joined: Mar 2012
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Paint blister
You might be able to see oil on the inside of the hood or it could have been cleaned off. I have seen contaminates come from tar based sound deadener the oil from the tar gets in the glass. Fiberglass is porous and absorbs things sort of like a sponge. Once in the glass its difficult if not impossible to get out of the fiberglass if it has started from underneath and worked its way to the top. Setting in the sun draws the contaminates to the surface. This is one of the reason many of us use epoxy primers to help seal the surface before painting. Where on the hood is the paint bubbling?
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From: Southbound
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Racer
Joined: Oct 2011
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From: NP Nebraska
- before I do anything costly/drastic. Does anyone have any suggestions? I'll try about anything before I replace that much fiberglass!