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™ is a registered trademark of Dow chemical and is a blue extruded sheet readily available almost anywhere. This type of foam is excellent for making signs and other display products. Coatings Both types of foam are easily coated with water-based paints like vinyl acrylics, and the paint is absorbed slightly into the surface of the foam by capillary action, thereby giving it a harder surface. Cement based coatings are also common, especially in the architectural field, and polyurea coatings are used for their hard, smooth finish. There are also the metal coatings from Plate-All and LuminOre. Advantages:Using shapes made of EPS foam offers many advantages over conventional materials Such as wood, plaster, concrete, and metal. It will not rot and warp like wood and is very lightweight, which makes it easy to install in the field. The shapes can be easily cut, mitered, and shaped (rasped)On-site with conventional tools. Design flexibility is unsurpassed with the use of EPS foam due to its Ability to be wire-cut.Foam is very inexpensive. When cutting the foam on a SCULPTOR HD foam cutter, the cut shapes have a very high profit margin. Foam is suitable for use indoors or outdoors. Foam can be coated with many different products to achieve any desired finish. Foam will last virtually forever if it is kept coated. Availability: Availability: Standard length for all shapes is 8 feet, and can be cut to exact lengths when specified. All shapes are available pre-coated (base coat and reinforcing mesh) and pre-mitered at additional cost.