: Clever. What kind of foam is that and how thick did your seat end up being? I
: like the idea and hope to do it so that my legs don't fall asleep

Well... I'm pretty sure it's urethane foam. This may be hard to find in a small quantity. You pour the two parts together and mix FAST, then pour the result where you want it. It expands to 30 times the original size. I have seen the stuff at some Home Depots, but not all carry it. It's sold for making repairs to dock flotation. I wanted the seat to be as low as possible, so I think I squished it down into the expanding foam until the lowest (mid-'cheek')part of the plexi was touching the bottom of the kayak. Now that I look at the old seat, I recall that I didn't glue in the minicel until after the pour-in-place foam had set up, and then I rounded the foam around the sides with a
Surform, and then glued the minicel over everything so that it rounds down to the floor of the kayak. Incidentally, I used the pour-in-place foam in the ends of my newest kayak for flotation, as it's a very open design. I hope this helps. Good luck!