Epoxy and Fiberglass
 

Looking for a little assistance. Recently purchased a fiberglass cap for my truck bed and trying to construct a rod holder inside, essentially straps hanging from the roof with rod tips going through the back window. I have been trying to epoxy a piece of wood to the fiber glass so I can then us the wood to screw into, but the epoxy has been letting go with in a few days. Using the 5 Min epoxy. Will epoxy not adhere to fiberglass? Product suggestions? Thanks in advance.

glue & screw

the inside of that cap might have some paint on it
have to sand off the paint

use real epoxy, not 5 minute and you may have to thicken the epoxy also, you can do that with a little wood flour which is basically fine fine sawdust

fiberglass caps may be made with polyester resin, not epoxy resin.

they usually are polyester... its cheaper.

also duct tape it up there... the humidity lately is gonna cause the poly/epoxy to take damn near forever to cure.

Thanks for the tips.

Did mine with construction grade Liquid Nails and its been fine for 2 years now and still holding.

Wipe the area down with some acetone, rough it up with 60 or 80 grit sandpaper and use some 30 min. epoxy(devcon 2 ton works great, or better yet use boatbuilding epoxy like west systems or raka). Like slipknot said, there may be some paint that you have to get off first and the acetone will degrease and dewax it so the epoxy will stick. If you just sand it without degreasing it, anything on the surface will just get pushed around and remain there preventing good adhesion.

Grind it and glass it. Like materials bond best to like materials, ie. glass to glass, epoxy to epoxy. Won't delaminate if prepped right. Use mat or cloth with the resin to give joint strength. Like building a mini bulkhead.

Sounds like the same epoxy the Big Dig used:hidin:

You can screw or through bolt a piece of wood in through the cap and seal the hole with either epoxy or silicone.