: I'm in the jewelry business and we make items using the lost wax method. This
: got me thinking (that can be dangerous).
: Glue a few blocks of white styrofoam together and cut to shape, then
: fibreglass the outside. After it hardens hollow it out through the opening
: you left for the seat. Leave as much foam as you want for strenth and
: flotation. The foam is easy to cut with a saw or a hot wire. Gasoline
: pored inside will melt the foam but you won't have the control you'd have
: cutting it out.
: Just a thought.
: Thanks
: Mark

Been done, works, result is not very pretty though. Solvents leave a mess out of PS so taking it mechanically out is better. Or you can use an epoxy that takes a temperature that shrinks the PS and it can be taken out much more easily.

TLM