Im in the middle of my jun build. Also fibreglass with some foam.
so first, measure your body and scale the armor properly. It might take a few tries.
What ive found works best is after pep, paint a thin coat of resin on the outside than after that hardens add resin to the inside focusing on getting resin to pool a bit in the corners.
Then add your fibreglass to the next coat, cut a few different strip sizes and apply it like paper mache to the inside. Youll probably only need one coat of fibreglass if you overlap them well enough but if you think the armor might get especially banged up, add another
Then clip any fibres that are sticking out, if there are bubbles drill them out and fill them with a little more resin.
optionally mix up some rondo and do the thinnest layer of that to smooth the texture and hide any exposed fibres that are left. Bondo is heavier than resin so do your best to not overdo it. thats how ive hardened my armor peices.
to clean them up i use a dremel to knock down the corners and a palm sander and normal bondo to even the surface.
By the time you have your base armor youll be a pro and be able to add all the extra stuff you want to make it emile.
