Auto body repair & detailing: Fiber glass to steel, hair fiber, roll pan

Question
Hi Mike I am installing a fiber glass roll pan on my truck.I want to make it seamless what will be the best thing to use to fill in the seams on each side of the roll pan where it bolts to the metal of the bed. I have got some kitty hair fiber glass bondo.Will it stay in the seam or will it crack.

Answer
It will eventually crack but not for some time. Fiberglass and steel shrink and contract at different levels with temperature change. You should get a few years depending on your climate. Make sure the metal is very clean before you start. Hit it and the fiberglass part with at least 80 grit or coarser for a good bond.