: A friend has done this and swears by it. He does say that he has to replace
: them every year or so though. I tried it with 2-part foam from TAP
: Plastics and decided not to use it. I had trouble getting it to leave any
: space under the lowest part of my butt and in getting the forward part of
: the formed seat in the right slope.

You can use the foam as a mold to make a fiberglass seat that will last for years.