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I'm looking for some help on a paint problem. The car is a 1962 fuelie which I have owned for ten years. When I bought the car it had a few pinhead size bubbles in the paint on the two front fenders and in the cowl area. In time, these bubbles multiplied which seemed to be caused by the sun and heat from the engine. These pinhead size bubbles ooze an oily substance. Two years ago I had the car repainted. The painter spent considerable time with DuPont's Technical support to come up with a solution for this paint problem. The fenders and cowl area were sanded to the original primer, set in the sun for weeks, baked with a heat lamp for days, soaked with acetone, baked again with a heat lamp, regelcoated and then repainted. The problem has returned!!! I now have a dozen of these pinhead size bubbles in the paint. I'm guessing that the problem may be from chemical paint stripper that soaked in to the fiberglass when the car was originally restored in the mid-1970s. Does anyone have any suggestions or ideas on how to solve this problem? The fenders are original and have never been hit. I don't want to cut out the infected areas unless I absolutely have to do it. Any information, ideas, etc., would be greatly appreciated. Thanks.
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Re: C1 1962 Paint Problem
Are the fiberglass panels original or replacements? It sounds to me as if your panels are degassing if there replacements. This was a BIG problem a while back and there is no fix that I have heard of. -
Re: C1 1962 Paint Problem
I have seen this problem several times. The causes are probably varied. I know one that had a considerable amount of engine oil on the inside and it came through, others have been some other contamination or stripper. There are no easy fixes that I know of. Are you sure that it was in fact gelcoated or was a urethane or epoxy coating used?Comment
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Re: C1 1962 Paint Problem
It sounds like stripper soaked into the glass fibers. the only cure I know of is to remove ALL of the paint & primer to bare fiberglass.soak/wipe panels down with thinner then wash with very hot soap & water a few times .when you think you are done wash it a few more times use strong soap like dawn or tide & the hottest water you can stand .then put it in the HOT sun for at least a week.the sun& heat draws the stripper out of the fibers .when they cannot dry because of paint they soak back in when it cools. anything short of this you are wasting your time . "gel coat wont hide it" BillComment
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Re: C1 1962 Paint Problem
Ted, first of all there seems to be some contradiction in the description that's confusing, at least to me. When you say "original primer", are you speaking of the dark gray primer that the factory used on the straight axles? If the car was restored in the 70's, did they not remove the "original primer", or did they only strip to it and fail to wash it off also? Does the car have all the original fiberglass in the effected area? As far as re-gelcoating, GM has never used gel coat on any factory panel, so I'm not sure if this was in fact done in the 70's or if you're just referring to the original glass surface.
If it's replacement glass, there have been some issues with a mold release agent that is silicon based causing the problems that you describe. I don't think these products were around until the 80's. I'd also be interested in knowing if by "original primer" you mean from the factory. If so, were these bubbles in the primer as well? It's hard to say if the problem is from the top down (some silicon based waxes will cause it) or the bottom up. Air conditioner compressor oil slung under the bottom of the hood will cause the inside out problem, although obviously that's not the problem here. As a side note, I would never put gel coat on a Corvette body. I think it's a bandaid alternative to solving several other problems correctly. If you do in fact have a widespread "inside out" problem, it probably involves oil or some silicon based product and I don't think it's fixable without glass replacement.Comment
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Re: C1 1962 Paint Problem
Quote: "Now that he has stripped the hood, he claims that there were 4 coats of paint on the hood and that any more than 2 coats of paint on the hood will blister from engine compartment heat."
BALONEYComment
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Re: C1 1962 Paint Problem
Could you elaborate on the "baloney" part of your message? I am as interested in the truth about what is going on as Ted is.Comment
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Re: C1 1962 Paint Problem
Why then is this type of blistering seem concentrated near the engine compartment? Or is it? What is the correct number of layers of paint that should be applied to this car? Does it differ depending on the type of material used (fiberglass vs. sheet metal), or part of the car? Thanks for your input.Comment
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Re: C1 1962 Paint Problem
I'm just saying that if a body shop manager said that multiple layers of paint on a hood, caused blistering from engine heat, like those we're talkin' about here, he's feeding somebody a pile of baloney (spelled balogna actually)Comment
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Re: C1 1962 Paint Problem
Kevin, in all honesty, I don't know the answer to that question, at least not without looking at the car carefully and very possibly not then either. Of the cars I own and the ones I've owned I've only had 4 cases of blistering. One is my 65 L79 air coupe. It has some blisters on the hood where the air conditioner compressor slung oil up underneath and it soaked through. As far as I know this hood is unrepairable. Another was a 63 roadster that I no longer own. It did it relatively soon after being painted and all over. (painted in laquer) I've always thought there were moisture issues in the paint application. My 60 roaster which was properly prepared and applied has a very few small blisters under the gas filler door on the rear quarter. This car was done base coat/clear coat by a local body shop several years ago after I stripped the original paint and primer which had one unprimed repaint on top. I've always assumed this is something petroleum related which contaminated the glass in this area although I've never known what. I don't recall noticing it in the original paint or primer. The third is my 69 L88. It's been painted since 1987 in laquer. The air cleaner element in the hood was replaced with a repop unit several years ago (just the foam) and for whatever reason, I went brain dead and didn't wash whatever oil was in it in the shipping bag off and it soaked through the hood leaving a perfect circle the diameter of the air cleaner and about 1" thick. I have other cars that have been painted in laquer at various times in the 80's and have shared the same storage enviroments as the others with no problems. I have a friend here who has an original paint 58 and original paint 65 and there are no blister issues with these cars. I am also in the process of stripping my original paint 59 and there's not a blister of this description anywhere, even though the car has never had any paint work and looks like it spent it's whole life outside. It does have some downright peeling from sun damage, but there are no small blisters anywhere, in the remaining paint or factory primer.
Back to your question, "why in the hood area?", I don't know. Really oily enviroment that got away??? Something spilled there and never addressed?? Some type of dumb mistake like I did in a smaller area with the L88?? Some type of poor paint process from the 70's resto??Comment
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Re: C1 1962 Paint Problem
The fiberglass is porous. There are strands of fibers that go from one side to the other. Each fiber acts like a small wick and carries moisture oil or any other contaminates from the underside to the surface. This eventually manifests itself as small blisters. I have seen latent stripper lie dormant in the glass untill acted on by a long wet spell when moisture brought it to the surface. I have seen oils of all types that came through with the same result. There is no easy fix. The surface of the glass can be ground and reglazed with mat and resin, or a good real gelcoat of proper thickness, or both may work, or the panel can be replaced which on anything but a hood and a deck lid, can be quite expensive too say the least.Comment
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Re: C1 1962 Paint Problem
Sorry for the "baloney" I posted on the discussion board earlier regarding the paint blistering problem. I have been duly corrected by more knowledgeable members. As it turns out, I misunderstood the guy at D&M painting my hood. He didn't say 4 coats of paint would cause the blistering. He actually said that my 59's hood appears to have had 4 separate paint jobs whereby the previous layers of paint were not stripped off. He thought that probably contributed to the problem, and/or improper prepping before one of the previous paint jobs. They are actually stripping my hood down to the fiberglass and following most of the procedures that have been suggested by others. In the genuine interest of trying to contribute to the membership, I inadverdantly offered a half-baked thought. As a newbie to the Corvette restoration world, I will limit myself to asking the questions in the future and leave posting answers to the experts in the group.Comment
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Re: C1 1962 Paint Problem
Kevin, if my comments made you feel uncomfortable I apologize. Nobody's an expert in all fields and that's what discussion boards are for. Fortunately, this one probably has the deepest pool of Corvette minds on the internet. If you've seen some of my other posts, I ask more questions than I answer. As for my "baloney" comment, I was directing it at what someone was telling you rather than the fact that you posted it here. There have been some technical answers by knowledgeable people on this site that I've disagreed with. To me, that's part of the learning process. This is really little more than a pool of opinions in many cases. I sincerly hope you won't change your attitude toward this group because of my comments.Comment
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