Reinforcing FRP fenders
 

Has anyone used the spray truck bed liner on the underside of their fenders to reinforce them? Im considering doing this before painting them so theyre not as prone to cracking. Any issues with this I should know or things Im not thinking of?

Why not add fiberglass to the backside then undercoat them?

why not just spray bed liner since I already have some?

I dont think the bedliner will do much and the issue with stiffening parts of the bumper is that you should use a flexible resin and even then it might just transfer to the next stress point and crack there. If they used a surface seal in the resin so it wont be sticky to the touch you have to sand every bit of it to get the truck bedliner stuff to stick. A friend of mine did his fenders on his kit car to try to quiet them down when rocks hit them and it all just ended up peeling off in sheets.

Best thing you can do is put the fenders on the car, spray them flat black and drive the car for a few months to see what happens, make your repairs then paint them when you paint the car.

So would an overlay of a sheet or two of carbon fiber help at all or do you think it would just crack the same at places regardless, like at the mounting points?

Aren't FRP products "Fiber Reinforced Plastic"? The FRP Downforce fenders I have on my S2000 have strategically placed strips of carbon fiber (mounting points, etc) for reinforcement.

Yeah, they have reinforcement around the corners and such but I was thinking more along the lines of the wheel well area...friend cracked his and I dont want the same to happen to me or at least give the fenders some extra rigidity.