Cracks forming in trailer skin...why?

[cracker39]

I have (or had…I’ll have to look to see if any is left) some “bar epoxy” that mixes equal parts like most epoxies. I’d bought several quart sets at a hardware store “yard sale” back in the early or mid ‘90s. I used some of it after 2006 and it was still mixing and bonding perfectly, so I think it has a pretty long shelf life. If I have enough left, I’ll test a small bit to see if it still hardens like it should, and if it does, I'll use it with some cloth on the front panel I’m working on. It hardens like glass when it cures. The humidity will be way too high today and tomorrow, but by Tuesday, the humidity will be down some and the temps in the lower 90s.

I had no problems with the fiberglass cloth lifting or moisture penetration on a kayak and sail boat that I built, and I used the polyester resin on both with glass cloth (exterior bottom, sides and top decking). I didn’t put cloth on the interiors of either, but I did coat everything well with the resin before priming and painting the plywood and framing. Maybe I just got lucky with those.