stress crack repair

[eddie Hernandez]

What is the proper way to repair stress cracks. Can i just used fiberglass resin, hardener or should I use both. The car just came back from media blasting so this is the time to fix this problem.

[George Skalkeas]

Re: stress crack repair

Eddie: the resin without the hardener is no good... it will never dry. If the crack warrants fiberglass repair you should use resin, hardener AND fiberglass matte.

[eddie Hernandez]

Re: stress crack repair

Im sorry I was clear, they sell resin with hardner, and fiberglass bondo. Im wondering could I fill the cracks with properly mixed resin or fill it with biber bondo.

[Chuck S.]

Re: stress crack repair

Eddie,

I seem to remember you have a '74 or '75. After '73, Corvette body panels are made of SMC (sheet molded compound). You have to use epoxy based resin to repair your fiberglass, where the earlier cars used GRP (glass reinforced plastic) panels and polyester based resin. The polyester based resin DOES NOT WORK on SMC body panels. Eckler's can recommend the right materials for your car.

If you are going to apply gelcoat after your body work is complete, stress cracks in low stress areas can be repaired with spray gelcoat if the cracks are not severe. Eckler's "new improved" gelcoat can be used on either SMC or GRP.

In high stress areas, like in the corners of headlight bucket openings or hood openings, the stress cracks have to ground out deep enough for three layers of fiberglass mat and resin. After the fiberglass cures, you grind the fiberglass down below the surface, apply body filler, and sand to finish contour.

This and other fiberglass repair procedures are covered in "Eckler's Complete Guide to Corvette Fiberglass Repair" which is available on the NCRS website.

Chuck Sangerhausen

[George Daina]

That depends on the cracks.....

You can have two kinds, (1) surface cracks that don't penetrate the glass, and (2) cracks that penetrate the glass.

Aproduct by USC called Durabond (I think) is a filler w/fiber strands, when curred, harder than a granite mountain. Use this product to fill in surface cracks. make a "V" chanel, but be carefull not to go deeper than the original crack.

The second crack, use resin & fiberglass matting, clean from both sides, and dig out the damaged area, even if you ga through the glass and make the crack larger. That's ok, as the matting from the front and rear will have a larger surface to bond to each other.

Good luck.