: I used foam to hold the seat in place on my fiberglass whitewater boat.

: 1) heat helps the foam to expand so use it on a warm day.
: 2) mix small quantities
: a) to reduce the amount of heat built up
: b) to reduce the preasures built up.

: I would start with 1 cup of A and 1 cup of B to get a feel for the process.

: 3) foam will trap water next to the hull bad (???)
: for a woooden boat.

How about using Foam to form a seat? Make a little box in,
the bottom of the kayak, cover the surfaces with saran wrap,
pour some foam, cover it and sit on it. Should fit pretty
well. Can clean it up with sandpaper and cover it with model
airplane covering for looks...