Foam Centered Boards

(Excerpts from ART HARDWARE: The Definitive Guide to  Artists’ Materials, by Steven Saitzyk © 1987)

Foam boards were originally developed for use in  the graphic arts, but have now found their way into the world of fine art.  Foam-center boards are lightweight boards made of a rigid plastic foam with a  paper or plastic facing. They resist warping, are more dimensionally stable than  boards made from wood pulp, and are far less acidic. Despite the many advantages  of this type of board over most paper boards, it cannot be considered archival  because the core is polystyrene, or some variant of polystyrene, and this  material naturally decomposes over a long period of time and is said to give off  acid vapors. This aging process is greatly accelerated when exposed to  ultraviolet light (some of the newer boards have UV stabilizers) and air  pollution. Some manufacturers have begun to buffer the surface paper to help  maintain an acid-free surface. In museum style picture framing, where foam board  is used as a backing material, it is not exposed to ultraviolet light and the  elements. This would make its use in framing quite safe as long as it is not in  direct contact with the artwork. Unfortunately, some artists think this material  is safe to use as a painting or sculpture material for fine artwork when they  learn it is used in museum-style framing. Unless foam board is thoroughly  covered-particularly the exposed foam edges-with enough paint to seal the  surface from air and to prevent ultraviolet light exposure, it will deteriorate  too rapidly for fine art.

Foamcore Boards

Foamcore boards are made with a polystyrene core  and either a white claycoated or brown Kraft paper facing. The original white  foamcore board was produced for the graphic arts industry by Monsanto and was  named Fome-Cor. Today there are several other competitors, as well as a generic  version. The way the polystyrene bubbles are formed during manufacture allows  the edges to stay sealed, or at least crimped, during die cutting. This creates  a characteristic pillow effect. It also means that any accidental impressions or  dents can permanently damage the board. The foam center is not affected by  moisture, but the surface paper is, and outdoor use as well as wet mounting can  be a problem. The surface will readily accept oil paints and acrylic paints, but  the foam is sensitive to some solvents, particularly those in lacquers and  shellacs. Fome-Cor cuts easily with a razor blade, if the blade is sharp and  without defects; if it is not, it can tear the foam instead of cutting it. My  experience with this particular board is that it behaves as if it had a grain  and tends to cut well in only one direction. This board is commonly used in dry  mounting and vacuum mounting, as well as in wet mounting when counter mounting  is done.

There are three types of Fome-Cor: original,  acid-free, and super thick. The original is made in two thicknesses, 1/8 and  3/16 inch, and four sizes, 20″X40″, 32″ x40″, 40″X60″, and 48″X96″, of which the  first two are most common. In the 3/16-inch thickness, there is a greater  variety of available sizes, but only the first three are readily found. The  surface pH is slightly acidic, 5.5 to 6.5, and it is for this reason Monsanto  produces an acid-free Fome-Cor where the surface paper is buffered to a pH of  7.5 to 8.5. The printed literature for this board suggests that it is archival  and may be used as a substitute for museum board. This seems questionable  because, for example, the surface of this board is made from a Kraft paper and  not a purified cellulose, or cotton fiber. It is uncertain how much alkaline  reserve the buffer can provide in neutralizing air pollutants and the natural  formation of acid during the aging of Kraft paper. There are also questions  about the permanency of polystyrene itself. This board is obviously an  improvement on the original; nevertheless I have reservations about its archival  qualities. The acid-free foam core is produced in thicknesses of 1/8 and  3/16-inch, and sizes of 32″X40″ and 40″ x60″. The super thick variety, called  Fome-Cor ST, is identical to the original board but is -1/8-thick instead of  3/16-inch. The available sizes are 30″ x40″, 32″ x40″, and 40″ x 60″.

Prime-Foam-X ® Board

Prime-Foam-X is produced by Primex Plastics  Corporation. With all its similarities to Fome-Cor, it has some significant  differences. The outer paper facing is thicker, whiter, and glossier. The  formation of the foam bubbles and their higher density in this board allow for  better retention of shape and minimize damage. This board is said to have  “memory” because slight indentations tend to heal themselves. Consequently, in  die-cutting the edges do not crimp or seal as they do with Fome-Cor. I have  found that Prime-Foam-X does not have any directional cutting resistance and  cuts well in all directions. It is manufactured in the same sizes as Fome-Cor  and is also available in an acid-free version. This board is now produced with a  UV inhibitor to reduce the possibility of ultraviolet light breaking down the  foam. There are two thicknesses-0.125 inch, or ‘/e inch, and 0.210 inch, which  is almost 1/4-inch thick and is thus often referred to as ‘/a-inch nominal.  Primex prefers to use thousandths of an inch rather than fractions in referring  to thickness. The surface pH is between 6.5 and 7.0 for the regular surface and  7.5 for the acid-free surface. Prime-Foam-X is a little more expensive than  Fome-Cor.

Gatorfoam® Board

Gatorfoam has a foam center of Dow styrofoam  polystyrene with a Luxcell veneer. The veneer is a multilayered,  resin-impregnated, Kraft paper surface. Styrofoam is a much harder form of  polystyrene foam and is much more durable, but does not have any better aging  properties. The hardness of the core combined with the Luxcell veneer results in  a board that can only be cut with a table saw, which significantly reduces its  ease for use in picture framing and storage. The major advantage of Gatorfoam is  its thickness, which ranges from 3/16 to 1′ inches. The 3/16, t , and 3/4-inch  thicknesses are made in 30″ x40″ and 40″x60″. One inch and 11h inches are  available in 48″x96″ as well.

Gatorfoam is manufactured with two surfaces, one  white, the other brown. The brown Kraft is better for receiving paint and for  mounting. There are also two grades: Gatorfoam I is the standard, Gatorfoam II  is a less expensive version with an expanded polystyrene foam center. This board  is primarily used in model building and as a lightweight substitute for plywood.

Gilman Board

Gilman board is like Gatorfoam II in that it has  an expanded polystyrene core, which is also known as block foam. The outer  sheeting, however, is a claycoated, white sulfate paper. This paper allows the  board to be hand cut by first scoring with a mat knife and then bending, which  makes it more practical for picture framing. Gilman board is produced in  thicknesses like Gatorfoam-from 3/16 to 1 inch, but only in 4’x8′ sheets.

Artcore

Artcore, manufactured by the Amoco Company, is  not a paper, or a paper surface foam board. It is entirely plastic. It is  polystyrene foam covered with a white styrene sheet. Since it is all plastic, it  is also waterproof. The surface sheet is treated with a UV inhibitor to reduce  deterioration from sunlight and fluorescent light. The nonabsorbency of the  styrene facing can, however, make mounting difficult. I have had areas of  several photographs separate from the surface after vacuum mounting. In fact,  after experimenting with this board I have found it has no advantages for  framing and storage over the paper-faced foam board. It would seem more  practical for making displays, models, and signs. Its surface pH is 6.0 to 6.5,  and it is manufactured in thicknesses of 1/16, 1/8, and 3/16 inch. The available  sizes are comparable to other foam boards.

(Excerpts from ART HARDWARE: The Definitive Guide to  Artists’ Materials, by Steven Saitzyk © 1987)