Adaptation of a Standard Industrial Peel Test for Testing Consolidants in the Conservation Studio

Abstract

ABSTRACT Adhesives and consolidant strength play a major role in many conservation treatments. In industry, adhesive strength is often determined using standardized tests including 90° peel tests. However, not all conservation studios have or can afford mechanical testing equipment for such tests, although it is often readily accessible at third-party facilities. For a university conservation project, an international standard 90° peel test was modified to study the adhesive strength of consolidants for zinc white paints. Consolidants were applied to painting canvas strips, which were then adhered to zinc white paint layers on glass supports. The strips were peeled downward by continually adding fine sand to a cup attached to the end of the canvas strips. Video recordings were made of the continual loading and sudden stepwise extensions of the peeling samples, so that step-wise force - peel length curves could be plotted for each specimen. The data combined with examination of the peeled surfaces provided important qualitative information over strength and toughness (ductility/brittleness) for comparing the tested consolidant-zinc white systems. The adapted peel test is therefore a valuable method for testing adhesives and consolidants in the conservation studio. However, one must avoid overinterpreting the results, since consolidant selection depends on more factors than just mechanical properties.