There are two typs of EPS suitable for tooling with a hot wire foam cutter:

Expanded polystyrene (EPS) is perhaps more common in everyday life — it is the white foam found in drink cups, coolers, insulation, product packaging, etc. It is made up of over 95 percent air and less than 5 percent of polystyrene. The styrene pellets are heated with steam so that they expand rapidly and form a block of low density foam. This kind of foam is inexpensive and light—it usually weights between 15-30 kg per cubic meter.  Although it does not degrade under normal circumstances, it is being often recycled.

Extruded polystyrene (XPS) has the same chemical composition as the expanded polystyrene foam, yet it is manufactured in a different way, and as a result this foam — having smaller air pockets — is denser and more homogenous. It is often pink, blue, green, etc. The extruded polystyrene foam is perfect for making any kind of displays.

Why foam?

There is a number of reasons for which the above two kinds of foam have such a wide range of applications. Generally, foam is:

• inexpensive
• light
• perfect for both indoors and outdoors
• suitable for a variety of coatings (water-based paints, cement-based coatings, metal coatings, etc.)
• durable— if coated properly, can virtually last for years