This study investigates the use and suitability of one flexible epoxy resin, G/flex 650 Epoxy, for the treatment of shrinkage splits in European Oak (Quercus Robur). Research of epoxy resins for wood conservation saw considerable interest through the 1980s-early 2000s. This did not continue as epoxy was often deemed too rigid with poor reversibility, resulting in missed opportunities for the conservation field when job specific epoxy resins were formulated. Assessing the range now available, it has been determined flexible epoxies could be of significant benefit to the field countering the argument that epoxies are too rigid. One over-arching aim for the project was chosen; to ascertain the suitability of G/flex 650 Epoxy as a filler element for splits in oak objects, with and without varying amounts of bulking agent (phenolic microballoons were selected as the optimal choice). To achieve this aim five objectives were set out. These were to assess the criteria of what makes a successful gap fill in shrinkage splits, characterise the physical and chemical properties of G/flex 650 Epoxy and the impact of phenolic microballoons on these properties, assess the preparation, application and curing properties of the filler, evaluate the suitability and performance of the filler and make recommendations as to the fillers use. Research methodology involved a review of relevant literature, useability tests to explore the specific preparation, application, and post-curing characteristics of G/flex 650 Epoxy, measurement of shrinkage rates, and adhesion strength tests to determine whether the relative strength of the epoxy is below that of oak, all of which explored varying concentrations of G/flex 650 Epoxy. The investigation found mixtures of phenolic microballoons in a 0.25:1 or 0.5:1 ratio with G/flex 650 Epoxy was well-suited to the requirements of repairing shrinkage splits in oak owing to its high viscosity, ease in carving and sanding and adhesion strength, with those of lower ratios deemed inappropriate owing to their high adhesion strength and difficulty in controlling the solutions. It was concluded that within the parameters of the study these higher ratios could be acceptable treatment options, although further testing on the ageing characteristics and reaction to fluctuating environments would be required to ensure their long-term stability.
Keywords:Â Epoxy resin; shrinkage splits; phenolic microballoons; flexible; testing.
PLEASE NOTE: You must be a member of the University of Lincoln to be able to view this dissertation. Please log in here.