Blobitos

Hi everyone,

Having recently move to CA from the UK I thought i would seize the opportunity to own a classic car that just don't exist across the pond. So i have picked up a 78' C3, running but in pretty shabby condition

One of the major issues is the body work, although there are no cracks or major impact damage, it has been heavily neglected and possible never repainted or protected. large portions of the front wings and bonnet are showing the red(ish) primer/undercoat which is heavily pitted, other parts where the cover has rubbed against it for a number of years are down to exposed fibres, however as this has effectively been gentle sanded off for many years is very smooth not like the paint has been chipped off and left sharp edges, and parts of the car look great, particularly down the doors/sides so I guess it was sun damage

I have done some reading and there appears to be two camps in relation to gelcoats on this era car, I have also read about varied success using boat paint/primers but given there are effectively 3 different finish levels on the car what is the best advice to prepare it for repainting? I appreciate I will probably have to sand back the red(ish) original primer as it pitted, but what about the good paint? Does it need to be taken back or can it just be roughed up a little for the new base to adhere to?
Also the exposed glass, does this need any filling or otherwise need separate protection will it be OK to use some sort of building primer directly on the fibres to bring it back up?

Easy Mike

Welcome!!

Post some pics of what you've found. You can see what you have, but we can't.

Blobitos

Apologies, I didnt actually have the car when I posted, it just arrived - here are the pics of the body work

Priya

I don't know what you read, but I don't think you read anyone suggesting a gel-coat on an SMC bodied 79.

ratflinger

It's been done, just recently read a thread where it was successfully done.

OP - you need to get in contact with a member named Dub, he is an expert on body work and can help you.

Priya

Is that right, eh? Very interesting, I don't suppose you have a link to that thread?

DUB

For what this is worth:

I have always wondered why gelcoat cannot be applied on SMC. I was always told that it should not be applied on it due to the resin used in the panel. Because I do know there is not just one type of SMC. The blends of resins changed. Keep in mind I also custom paint jet ski's, boats and any thing else you can kind of think of that uses SMC as a material to make the body.

SO...if a polyester product can be applied on Corvette SMC panels...why would not a gelcoat. I have often times wondered that BUT I have never used a customers Corvette as a guinea pig and test it on it ONLY knowing that if something went REALLY BAD...I would have to do it all over again at my own expense.

Much like most products. They can be applied on a surface and hold for a while and then one day. WHAM...they begin to lift, bubble, check, craze or any other type of problem you can think of. DO NOT ask me how I know this because I have seen it...and had to fix it all over again. Sometimes it can happen in a few days. I am now thinking of a paint job 'horror story' that occurred that comes to mind on teh day of delivery .... it had to be all done over again..

Now I will apply an epoxy primer and then a polyester primer which will provide me the build I need....but not yet quite the same advantages that gelcoat provides.

And knowing that this method has given me numerous Corvettes that I have done that came in looking like the one in this thread and some MUCH worse. I would not think twice about being able to fix it and the procedures and products I would use to fix the bad areas.

Knowing that the polyester press molded fiberglass on earlier year model Corvettes is NOT that same as the first designed SMC used on the later year model Corvettes up to 1982. The properties of substances that can absorb into the polyester press molded fiberglas and SMC are still basically the same. SO...oil, tire shine silicone and brake fluid ,etc IF left on a panel will soak into each panel and will cause a problem. I know this becasue I have seen it and have had to repair it on both types of fiberglass.

SO....if a person wants to gelcoat their car...have at it. So far....in 30+ years. I have yet to have an SMC Corvette bubble in the C3 era. I have had issues with the 2 1984's. Where the body panels would cause the primer to blister off and to fix that I had to cut out the contaminated area of SMC and put new material in. Once I did that....the problem did not come back.

SO...knowing that these areas can be fixed. I guess I need to know how far you want to take this...and what are you expecting when you get it done.

So...could this rest of the car that still has paint on it be prepped and not stripped off. YES it can. But I am not there to actually look down into the paint and see if I see cracking , crazing or bubbles.

As for fixing the rough exposed fibers. There is not an easy answer due to I am not there to test and see how far the fibers literally powder away when I grind on them ...and then finally get to good solid body. Sometimes the fibers are damaged only on the top and it is superficial...which the repair is different than IF the body material has been really damaged and you ALMOST grind through the body due to the resin has been damaged thought the entire thickness of the body panel.

Even if you grind the fibers and you get to good solid body material. I then look and see if I see staining in the color of the SMC. IF I see staining. I grind it almost all the way out and apply new material so I do not have to worry that....just because the fibers were solid enough to support a grinding disc...it can be bad enough to cause for a paint issue later due to contamination in the SMC material itself.

I KNOW this to be TRUE. Becasue a SMC quarter panel that was saturated on the underside where the tire shine that slung off the rear wheels on a C4 and caused the paint to bubble.. When I ground on it with my grinding disc...the dark stained SMC sanded off and it made dust and NOT a goo. And I could clearly see where the silicone stained the SMC.

DUB

derekderek

DUB, do you ever deal with Joann at Crazy Horse Custom Paint?

DUB

No. can't say that I have.
DUB

Blobitos

Wow Dub, that’s an awesome response thanks

ill have a more detailed look at the exposed sections and try to assess how deep the damage is

Then would you recommend the epoxy primer first then polyester assuming the glass still has a decent amount of resin around it and doesn’t need repairing or repairing?
My goal at this point is to get a passable paint job myself, mostly for protection as this will never be a show car, I will be endlessly tweaking and tuning and maybe racing so will seldom be “finished” but would like it to look half decent from 30ft when I’m rolling through Santa Cruz

ratflinger

https://www.corvetteforum.com/forums...r-gelcoat.html

It was chrome bumper car though, so I may be speaking out of turn.