Foam Technical Information
The most common types of foam which are suitable for cutting on
a hotwire foamcutter are expanded polystyrene and extruded
polystyrene.
Expanded Polystyrene Foam: Expanded polystyrene foam is used for
coffee cups, coolers, insulation, packaging products for
shipping, etc. It is made up of about 2% polystyrene and 98%
air. It is manufactured by heating styrene pellets with steam so
they expand rapidly within a mold and form a large block of low
density foam. The expanded beads remain as air filled closed
cells that resist the conduction of heat, and therefore are
efficient insulators. This foam is light, usually 1 to 2 pounds
per cubic foot, and very inexpensive. No CFC's are used in
creating the foam. It doesn't degrade under normal circumstances
because EPS is inert and has a very stable molecule. Foam is
increasingly being recycled, to the benefit of the environment.
Extruded Polystyrene Foam: Extruded polystyrene foam is the same
chemical product as the expanded foam, but it is manufactured
using a different process which extrudes the foam, resulting in
a denser, more homogenous product with much smaller air pockets.
It is commonly found in sheets of 2 pound per cubic foot density
or higher, and is usually colored blue, green, gray or another
color. Styrofoam