For prototyping our wingsails we decided to use polystyrene: it's cheap, easy and quick to work with. Moreover, there is a concrete chance that even our final wingsail will have a foam core (although not polystyrene).
Given that foam will be with us for quite a bit of our adventure, and since the Magellan Machine headquarters are located in El Cheapo, we decided to build our own hot wire foam cutter.
On the internet there are several how-to's for building them (apparently El Cheapo is the silicon valley of RC planes enthusiasts), but all of the designs I saw had a couple of characteristics I did not want to deal with.
