Thread: Who knows how to repair cracks in fiberglass?

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I have an 85 Vette, and the original fiberglass targa top is severely cracked. My Dad and I think it was either dropped, or maybe it even blew off of the car. Can someone give me step by step instructions for repairing the fiberglass? I would greatly appreciate any help you can give me
Zak

it would be SMC not glass and it would be hard for me to give you step by step but you first need to get the wax off it V out the cracks and make up small strips glass mat as you add a strip you want it to be just a bit bigger and wider than the first to put in the V out try finding fiber gell made by swiss that works good try to post heat it and let it cure

I think the last year for fiberglass Vettes was 1975. After that they wee made of SMC (sheet molded compound) With out seeing it I would guess it could be repaired with Panel Adhesive, it's the same stuff as they use when they glue them together.

Bob

no 75 was smc and vett bond is not to good for that kind of work with out a backer what i have seen i think late 60 for glass

Would it help if I posted pictures for you guys to see? The cracks are pretty bad, and I started to sand it down today. The previous owner already tried to patch it, but it will probably have to be replaced. Also, how far do I need to sand it down?

Originally Posted by pat mccarthy

no 75 was smc and vett bond is not to good for that kind of work with out a backer what i have seen i think late 60 for glass

I'm sure the SMC started in75 or 6. Didn't the tin floors start in 74 or 5 ?

So what do I need to do to get this repaired? I can post pictures and you guys can take me through it. Just let me know what I need to do.

you want to lay it way out from the crack thickness less than 1/6 of a inch and V feather back. to build it back with mat this is the only way to make it strong mat or cloth makes the part strong on the gell or resin i use and 36 grit on a 3m 8inch soft pad

Do you want me to post some pics of it? how much do I need to sand?

Originally Posted by Bob W

I'm sure the SMC started in75 or 6. Didn't the tin floors start in 74 or 5 ?

the last one i work on was a 65 white glass?? mild year . 75/76 front rubber bumper all i know is i was thinking i work at a shop that did the a 75 i was thinking? and it was all smc and they used vett bond look good till they roll it out it the sun i have seen smc parts on mild years and header on the gm cars wer smc back past 75. 69 had glass foors???steel bumper car were glass ??

Do you want me to post some pics of it? how much do I need to sand?

Originally Posted by Corvette85

Do you want me to post some pics of it? how much do I need to sand?

well i would need to see it so post away

On the outside of the panel, V out the crack, then rip up some matt into shreads, brush on some resin, and work the fibers deep into the crack. If the cracks are severe, or chunks missing, then grind the inside of the panel with 36 grit and put a layer of matt on the inside. Before laying matt on the inside, use the method of shredded matt to fill the holes. After this has all dried on the inside of the panel, scuff it again with 36 grit and apply a layer of cloth that extends beyond the area you placed the matt on. For large repairs on 'glass bodies, I use core matt, or kevlar matt to add a bunch of strength to the repaired area... Might not be the way the reps say to fix it, but it works for me!!!!!

Here are several pictures.

Here are a few more.