: Question 1: Is GE RTV 100 adhesive sealant a good choice to seal bulkheads?

Not sure, but I don't see why not.

: Question 2: I want to put a layer of fibreglass and epoxy over foam (the type
: of foam found in seat cushions) and I wanted to know if anyone out there
: knows if it will bond properly.

I think it will probably bond ok to the first couple of mm of the foam, but any movement or flexing would shear the foam. The question for me is why would you want to do this? That stuff is too expensive to use as a mold.
IMHO, anyway
James, STILL not finished his GB , Neely