(Excerpt from ART HARDWARE: The Definitive Guide to Artists’ Materials, by Steven Saitzyk © 1987)
Vacuum Mounting utilizes an adhesive in combination with pressure to mount and flatten the artwork. The adhesive is usually applied to the back of the art-work, which is then placed on the mounting board and both are put into a vacuum mount press. The vacuum mount press removes the air to create a vacuum, which in turn presses the mounting board up against the top glass cover with tremendous pressure, flattening the artwork and forcing the adhesive into the two surfaces. This creates a strong bond. There are a number of special advantages to this system. Heat, for example, which might accelerate the aging process, is not used. In addition this system can be used for wet as well as dry mounting with a spray, not with tissue.
In wet mounting, blotter papers are used in the vacuum mounting press to keep the work flat and to accelerate the drying time. The vacuum forces some of the moisture into the blotter paper covering the artwork in the press, and, if the blotters are changed frequently, the drying time is greatly decreased. This is important because if the mounted artwork takes too long to dry, mold may set in and damage the artwork. A wet mount in the vacuum mount press is usually reserved for jobs that require a water-reversible archival mounting.
There are a few companies that make vacuum mount sprays. 3M offers a spray, which is currently the brand of choice. A vacuum mount spray is designed to allow you “open time” of two to eight minutes to reposition the artwork for placement. This means that after the back of the art has been sprayed there are approximately two to three minutes of waiting time until the tack is reduced so that the surface is sticky, but will not bond firmly without pressure. The next two to eight minutes may be used to position the artwork. This unique feature allows precision mounting, and I have used it with a number of contemporary artists to create artworks that could not have been created in any other way. After ten minutes from first spraying you must place the artwork in the press for permanent bonding. The 3M Vacumount Spray Adhesive is pH 6.8 (which is essentially pH neutral), holds up well under accelerated aging tests, and is only reversible in organic solvents, not in water. It is important to note, however, that the use of sprays such as these require the use of personal protective equipment and proper ventilation. (See Hazards.)
Vacuum mount presses are available in sizes up to 48″ x84″, but the most common are those that will handle up to 40″ x60″ boards. The system allows for the use of almost any type of mounting board, even sealed wood up to %-inch thick, but, as with any product such as this, the technical specification and limitation must be read first and followed accurately and completely.