Relatively heavy three-dimensional wax fragments, which cannot be consolidated due to their low porosity, have a particular need for ethically reversible or re-treatable adhesives that are also stronger than natural polymers. However, the only adhesives that can be safely used on culturally modified wax blends are those which are both delivered and reactivated in water. This study evaluates existing approaches to repairing wax objects through conservation literature and modern case studies, and investigates the properties of three commercial conservation (poly)ethylene vinyl acetate (EVA) adhesives in order to gauge their suitability for use in new treatment methods. The water-reversible EVAs in this study are Evasol by Book Restorations, EVA Neutral pH by University Products, and the formulation of Evacon-R™ by Conservation By Design that was discontinued in 2014. Their suitability for use in collections is investigated through the ‘Oddy’ accelerated ageing test as well as a newer experimental method of measuring atmospheric yellowing through nitrogen oxide exposure, pH testing, and compositional analysis with Fourier-transform infrared spectroscopy (FTIR). The adhesives’ ageing properties appear to be linked to their trace biocidal components. The instability of bronopol is identified as a particular problem for Evacon-R™ and, to a lesser extent, EVA Neutral pH. Following the results of these tests, Evasol was successfully used in repairing a series of wax portraits at the Royal Albert Memorial Museum (RAMM) in Exeter. Future proposed directions for wax conservation methods include the continued investigation of EVA-starch paste blends.
Assistant Conservator, Natural History Museum of Los Angeles County
Marina Gibbons is the Assistant Conservator at the Natural History Museum of Los Angeles County, where she treats natural history specimens as well as cultural heritage objects. She is a graduate of the dual-Masters conservation program at University College London (M.A., MS.c... Read More →