Foam board, also known as foamcore or foam core, is a backing material widely used in framing art. It is made of a type of Styrofoam™ covered on both sides with paper or plastic so that the foam is the core of the sandwich. This material is usually white, although some manufacturers also offer it in black. It is 1/8 or 3/16 of an inch (0.3 or 0.5 centimeters) thick.
This material is very lightweight as well as strong, which makes it ideal for framing large works of art or posters, since it adds so little weight to the overall piece. Its rigidity stabilizes paper art, but be warned — it is not truly archival. Styrofoam™ does break down over long periods of time, and a byproduct of this decay may be acidic and could hasten the aging of the art it is framed with.
Foam board can be purchased in very large sheets, which has led to its second-most prevalent use as display boards for school projects and science fairs. Three large boards can be hinged together by applying white artists' tape to the joins on one side to make a trifold or triptych display.
Because the surface can be pierced with thumbtacks or pushpins, foam board can make a great disposable bulletin board for a fraction of the cost of corkboard. When the surface gets too full of pinholes to be used any more, throw it away and buy a new board. If the surface is slick enough, dry erase markers can be used on it as well to create a makeshift whiteboard. One piece on a dorm room door makes an all-purpose bulletin board/whiteboard combo.
The foam is easily cut into shapes with a razor-type knife. It accepts paints and felt-tip markers and fabric can be glued to its surface. For these attributes, foam board has replaced balsa wood as the modeler's choice for building material. If your collection of pewter knights needs a castle battlement or your action-figure star pilots need a space dock, this material, a knife, paint, and glue can create the backdrop and props for your specific needs.