Hi, the floors on my 76 300D are in pretty good shape, but I was getting some rust on the passenger rear. I took most of the coating off the floor in big hunks and can lay most of it back in place. Coated what I needed to with miracle paint (2 coats).

I'm considering pouring in something that will harden and give the floor some extra rigidity and allow me to put the original material back down if I want.

Has anyone done this? I'm thinking maybe about a quart of 2k Epoxy primer? Or maybe some kind of fiberglass resin?