Agree but a breadknife like a "kitchen devil" works well if you haven't got a bandsaw. you don't need an electric one, although it it probably easier that way, just don't apply pressure and let it cut without distorting the foam.
For intricate shapes soack the foam in water and lay flat in the freezer, once its solid cut with a jig saw. We used to do this to cut specialist foam inserts for equipment cases.
[/ QUOTE ] I am always a bit wary about hot wires from the toxic fumes point of view. They always tell us about toxic fumes being produced from furniture when burning.
But that's polyurethane foam and it, they tell us, produces HCN ???????????
The soft foam in boat cushions is presumably polyether so should be safe. ??????????
I cant see any improvement on the electric carving knife. The thing the professionals use has a similar action I think you will find. (A bit like a double bladed jigsaw)