Consolidation of objects in a solvent vapor saturated atmosphere: A new technique for minimizing changes in appearance

Eric Hansen, Rosa Lowinger and Eileen Sadoff

Abstract

Changes in the appearance of a matte powdering clay or ochre paint which results from consolidation with a solution of a thermoplastic resin include darkening, discoloration or increased gloss. These may be minimized by applying the consolidant in an atmosphere saturated with vapors of the solvent used to dissolve the resin. In addition to maintaining the original appearance of the object, other benefits include the absence of a tide line and greater penetration of the solution for improved adhesion of the consolidated paint to the substrate. The low cost of the plastic glove bag used to maintain the vapor saturated atmosphere and the portability of the system make it easy and inexpensive to use.

At the present time, we are limiting the use of this technique to objects, or areas of objects, which are not sensitive to solvent vapors. 5% solutions in acetone of Acryloid B-72 and polyvinyl acetates yield results as effective as those found with diethylbenzene without the problems associated with DEB. These include long term solvent retention and noxious properties, among others. We believe this technique is considerably premising for two areas of materials: clay, ochre, ceramic, terracotta, brick or other powdering and/or crumbling inorganic surfaces with little potential for solvent interaction; and flexible objects such as baskets, painted wood, etc. where a more flexible polymer than B-72 is desired. The theoretical basis for the observed phenomena is presented along with the results of consolidating ochre or clay with B-72 or PVAC in solutions of acetone, toluene and ethanol.