The styrofoam molds were placed in a bucket full of sand, and the furnace – a few ytong bricks, a crucible, and a propane burner – started to melt some aluminum.

LEGO 3-axis Styrofoam Cutter - YouTube 'Styrofoam cutter' is an item that can cut polystyrene foam smoothly using heat.

CNC Foam Cutters are capable of cutting out some pretty cool shapes that would otherwise be extremely difficult to do. They do this by pulling a heated metal wire though a block of foam.