I have a 1980 C3 that has spider cracks in the top side of some panels. I know the gel-coat will have to be removed and replaced. My question is do I remove all the gel-coat until i start seeing the fibers? and what is the best thing to replace the gel-coat with? The problem is the complete topside of both front fenders will have to be done.... large areas ... Also I have some damaged area what will need fiberglass repaired what this the best fiberglass to use? Last thing I'm replace the driver door what is the best adhesive to use?

thanks

 

First things first. Real 80s dont have any gel-coat, so if you got gel-coat it is an after market part. Before you can be advised how to proceed, we would have to know.

How in the crap did it get damage to the whole top surround? Are you sure you are dealing with spider web, crows feet, stars, or are you dealing with bad and checked paint?

 

I removed the paint and I can see the cracks in what ever that top coat is. The panels are not aftermarket... The cracks are hard to see but they are there because they showed though on the paint job. I think the car was left out in the sun.. What is the top coating made of if it's no gel-coat? The coating looks to be around 1/16 thick.

 

It should be an SMC panel, which does have a fairly slick surface that could be confused as a gel-coat. To repair any crack in SMC you need to use an epoxy material to be sure of good adhesion. You need to use a product intended for surface application. There are some polyester based products that are intended for that purpose, but beware, polyester doesnt adhere as well as epoxy. It may work OK, and many here recommend it, but it doesnt adhere as well. When done with all repairs, I recommend an epoxy primer over the whole thing.

 

You will find factory color coats, factory primer, and bare fiberglass in that order as you work down.

Factory SMC panels kinda look like gray marble and are smooth. I'm wondering whether the spider cracks in your paint were simply 40 year old acrylic lacquer.

For the door skin, you will need an SMC compatible bonding compound.

 

The problem you're experiencing is caused by stones and debris being thrown up by the front tires and hitting the underside of the fenders. I had the same problem way back when I first got my C3. You have to do some prevention before repairing the damage. If you feel the underside of the front fender you will see that there is no wheel well liner at the top, only at the front and rear of the wheel well opening. To protect this area I glued a dense foam, actually a piece of thick foam floor mat like you see at dept. stores. It's about 1/2 inch thick and I used liquid nails to glue it to the underside of the fenders. It's been there almost 20 years and I've never had a crack in the fender since it's install. I assume you could use more modern products like Dynamat but they weren't available way back then.

More than likely you do not have damage to the panels. What you probably see is the paint cracking because of the hits from below. Remove the paint from the bad areas and then take a rag that has lacquer thinner on it and wipe the panels. If you see lines in the panel while the lacquer thinner is evaporating you probably have cracks. But I'm betting you won't see any. If all you have are some hair line cracks you may be able to repair the damage by spraying the top of the fenders with gelcoat. Others may be more experienced in this area of repair than I am so I'll leave it to them to post some alternatives.

But first fix the underside of the fenders. Good luck.