austinseanchris

Alrighty folks, well, I dont know where to begin with this so I'll just jump right in the thick of it. Over the last 6 months, I have noticed my paint on my 96 starting to "bubble" or "blister" so to speak and its getting progressively worse, very quickly! It is only in 2 spots and its identical locations on each side of the car. Imagine continuing the T-bar panel(between roof panel and hatch glass) down the sides of the car(behind the driver and passenger door) about 3 inches. This is where the matching spots are located. The driver side is worse than the passenger, but it wont be long before its worse. When I bought the car 3 + years ago, I noticed a small blemish in the paint there on the drivers side. It appeared to be a small tiny line in the paint(almost like a crease under the paint itself). It was very hard to notice unless you were really searching. With that said, the rest of the car looks great as far as the paint job goes. I do not how old the paint is or know who painted it prior, but they seemed to do it right. You can tell panels were removed and door jams, engine compartment, etc is painted to match and clean. Nonetheless, since spring of this year when I started hitting the local shows, I started noticing more of these bubbles popping up under the paint itself. They are contained in an area about the size of a silver dollar and are no where else to be found on the car. I've noticed as the vehicle sits out in the direct sunlight, another blister or two will appear per 4+ hours. Then, an oily residue will begin running down the side of the car and you can wipe it off with your fingers. As much as I want to continue showing my car, I dont want the paint to continue getting worse. Sitting in the garage, it does not get worse...obviously it is out of direct sunlight.

With all of that said, I decided to get a few opinions from some local painters. I wanted to share this info and maybe get some other opinions from some fellow C4 owners as maybe they have experienced the same thing?

The first guy I showed stated he felt it was either A. Previous paint or debris left over from the preperation of the new paint job. or B: Oil residue from someone's hands that they may have put there hand there when sanding the lower part of the car when they were getting it prepared for new paint. Now, I painted my 78 and to be honest, I could relate to the "putting the hand there" idea when sanding b/c I'm a tall guy myself and used that to balance on. HOWEVER, obviously I prepped the car well but had no issues with oil coming out under the paint years later. My gut feeling is that neither of these is the issue...

The second guy I showed the car to has been painting cars all his life and is pretty well known locally. With that said, he came right out and said he was 95% sure he knew what it was. He said, being in the same place on both sides points to something other than paint. He stated back in the 90's, he had NUMEROUS Camaro's that he had roll into his shop with similar bubbles on the T-Bar. He said, I'd sand them, prep em and paint em. They'd look great and a year later, they'd be back with bubbles again. He said after 2-3 like this, he said they'res gotta be another culprit. Come to find out, he said he had a GM rep come down and stated apparently there was a recall on these cars b/c GM used some sort of adhesive underneath these T-bar panels and over time and in sunlight, that adhesive would turn into like a tar-type substance and seep thru the SMC panels under the paint and create these panels. He said after learning this, when these cars would come in, he said he'd have to cut the T-bars off the car, go in under that panel and remove all the old GM adhesive and replace it with a different glue that would not seep thru the SMC over time. Obviously he said this is a pretty involving process...cutting out body panels, fiberglassing or bondo-ing them back in, sanding, blending and painting. He stated being in the same location on each side, I'm leaning towards that idea of an adhesive to attach panels seeping thru the cars body over time. To me, this seems more realistic of what it could be...?

SO, with all of that said, I've been trying to eyeball C4's like a hawk as of lately. You know, seeing if there's any others having this problem. He stated Camaro's with these problems are a dime a dozen? My question to all of you are have you guys ever seen or heard of this on our C4's? He says it can be fixed but he feels theres more of a chance of screwing something up even more as opposed to just leaving it alone until it gets extremely worse. He said he'd have to cut out that area, remove the adhesive underneath, then use a SMC filler to build it back up. He said theres a chance over time(since the body would be weaker there now), that the clear coat could crack, blending issues, different shades of clear, and so on. He said he felt, I'd be creating more problems trying to fix this than to just leave it alone as is. I just feel like, theres gotta be a way to fix this w/o saying, its gonna look worse in the end and theres no 100% guaranteed fix.

I know this was long and drawn out, just wanted to provide all info I could. I attached a few pics below so you could make your own assumptions/recomendations. Thanks for reading and for any help/advice you may have!

DRIVERS SIDE:
[IMG][/IMG]
[IMG][/IMG]


PASSENGER SIDE:
[IMG][/IMG]

SoAlVette

I have similar on the driver side of my 95. I've wondered what the cause was. Mine is not as bad yet, but sooner or later I will have to deal with it.

austinseanchris

No offense, but good to know I'm not the only one then...

SunCr

Go back to your body or paint guy and ask him to measure (depth) the thickness of the paint. That usually tells you if it's re-paint or original. I've never seen this on a Vette, but I've had no reason to look for it. The only recall I know of was for the '89 - white only; yellowing around the headlights.

LannyL81

Has to be a repaint as that color was not available in '96....at least to my knowledge.

austinseanchris

Yes, it has been repainted...car was originally Torch Red.

powerpigz-51

A good DTM epoxy primer goes a long ways towards solving these kinds of problems. Goes on like bedliner and is hard to sand, but gives you the best chance of avoiding this.

ch@0s

For refrence here is a bubbling panel on a 4rth gen.

austinseanchris

Ehh...is this what I gotta look forward to? Is this your ride? How long did it take to get this bad?

ch@0s

Its not my car.. Painting it won't fix it, the glue used to hold the panel on actually comes through. So, the panel has to be removed and a new one has the be glued on.
There is a TSB from GM for the 4th gens.

austinseanchris

Ok, but is there glue used right behind the door on the C4's?

duramaxsky

On the newer paints if the clear is too thick solvent remains in the paint and this is what it will do. I made that mistake once. Its not like the old paints where you could build up a lot of clear and sand and buff to perfection. Lucky for me it was just a targa top so I sanded it all off and re did it. Hot sun is what made it happen.

austinseanchris

Makes sense, but my concern is only in these two small areas? Wouldnt it have spread all over the car?

duramaxsky

Unless the painter overlapped there in the spray pattern. Mine only did it in a few small spots but it was too thick on the whole top. When I sanded it off you could smell the solvent everywhere and that was a year later. As soon as the paint store employee looked at it they knew what it was. The new paints take 30 days to flash out the solvent and if its too thick they wont. Or so I.was told. I.am not an expert.

austinseanchris

Gotcha!

zr1fred

Most new primers/paints are epoxy, so there isn't a lot of solvent action. Lacquers used to be real bad for this. Paint stripers can also cause the problem. Sometimes chemicals will react with the SMC materials creating a gas which causes the bubbling (like in the LS Camaro roofs), or you could just have bad SMC in that area. Once you have the problem you can try various things, but panel replacement is generally the only cure.

wlean99

yea, reminds me of what we used to call solvent POP.As you stated to many coats of lacquer w/not enough drying time in between coats.Bottom coats still trying to Dry while top coats are dry already. lacquer polished up real nice but sure was persnickety .

Lloyd Smale

its caused by drying paint to fast. Drying it to fast traps the chemicals that needed to flash off under a skin of dry paint. It also sometimes is caused by paint not bonding to primer or primer not drying enough and again traping solvents. You dont see this kind of crap anymore with the new water based paints.

zr1fred

Not as often, but it does still happen, though for different reasons. Witness the "B" pillar on the 98-02 F bodies.

GKK

That, is just bad prep work on your repaint.

Several, coats of Polyester primer After a thorough wet sanding and wiping down of the surface will result in no bubbles or blisters...