AN EPOXY/MICROBALLOON MIXTURE FOR GAP FILLING IN WOODEN OBJECTS
R. Barclay, & C. Mathias
EPOXY RESINS HAVE NOT FOUND FAVOUR in conservation due to their potential for inflicting damage on surfaces to which they are applied, and also to their non-removability once cured. The application described above circumvents these two issues by treating the fill as an essentially separate unit, not bonded physically to the wood. Provided that suitable precautions are taken in its application, this fill material surpasses many in current use.
The filler described here is best suited to applications in which movement of the wood due to fluctuations in humidity is considered minimal, such as the weathered wooden structure illustrated in Figure 1. However, due to its low compressibility, it can also be used for filling cracks in sounder and more reactive wood. It should be remembered that the tests described above use only sound western red cedar because this is a weak wood, with a low modulus of compression and low strength across the grain, and thus serves as a good model for deteriorated woods. Clearly, the compressibility of other woods will differ and appropriate tests should be conducted as necessary.
THE AUTHORS WOULD LIKE TO ACKNOWLEDGE the valuable input and advice of Dr. David Grattan at all stages of this section of the research on fill materials for wood. We would also like to thank Sue Maltby for her trial work with the fill material on totem poles and for her tests of potential release materials. We are indebted to the Canadian Museum of Civilization for permission to publish the photographs of treated objects.