LETTER TO THE EDITOR
1.1 To the Editor:
I would like to correct a misconception implied by Gustav Berger in his article entitled “On Hot-Melt, Heat-Seal and Hot-Set Adhesives” (JAIC 18 (1978), 44–45). In it he refers to terminology as spelled out in “Adhesive Glossary” published by the American Society for Testing Materials, and “Adhesive Handbook” by J. Shields. Mr. Berger's article objected to D. Goist's use of the term “Hot-Melt” P.V.A.-AYAA, AYAC in his paper “Treatment of a Flood-Damaged Oil Painting on a Solid Support.” In regard to this I would like to direct your attention to the literature from Union Carbide, manufacturer and distributor of P.V.A. In their Products Standards Description, September 1972, F-42794B they say “Bakelite AYAA resin heat seals rapidly and can be applied as a solution or as a Hot Melt.”
In using P.V.A-AYAA, AYAC as a lining adhesive, it is helpful to understand what takes place. Heat seal adhesives such as Beva become tacky when heat is applied. This is also true of AYAA and AYAC, but with the additional characteristic of flow (Hot Melt). When heat is applied, AYAA and AYAC become viscous with enough flow to reach into the recesses of the linen and grab hold of the outer layer of threads without penetrating the fibers. Because of this flow quality, it is misleading to couple P.V.A.-AYAA, AYAC with Beva.
Especially because of this flow (Hot Melt) it is proper to differentiate it from adhesives with only Heat Seal behavior. Beva does not possess Hot Melt qualities, and so because of the unique nature of the P.V.A. adhesive I believe the language we use should reflect the differences. It is certainly more accurate and applicable. It behooves us to be more professional and precise to meet the exacting demands of our work.
In the same article, in dealing with wax resin, Mr. Berger states that “when applied it often stains.” A competent conservator would test, and not subject a work of art to such a result. To cope with such instances a P.V.A.-AYAA, AYAC lining system was developed.
In ending I would like to repeat the last sentence of Berger's article: Such inaccurateness tends to spread, and soon conservators in the United States may no longer be able to discern between desirable and damaging qualities in the materials they use.”BernardRabinPaintings Conservator, The Art Museum, Princeton University, Princeton, New Jersey 08544