NOTE ON THE DIRECT APPLICATION OF PLASTER OF PARIS TO WATERLOGGED WOOD

Abstract

With reference to the article below [1] a mould of the stern-post of the Graveney Boat which had not been moulded in 1970, was required by the National Maritime Museum. The stern-post was made of oak and measured 300 cm in length, 35 cm at its widest point and 10 cm at the thickest section. After discussion with Christopher Gregson, Conservation Officer at the National Maritime Museum who was to assist in the moulding operation, it was decided to experiment with applying plaster of Paris directly on to the wood save for a thin wash of diluted modelling clay. Clay is a natural release agent for plaster. This having been carried out, the plaster was successfully removed from the wood-surface without causing the least damage. Subsequently a ten-piece plaster mould was made of the stern-post as previously described. Only where the wood was extremely fragile was it necessary to use paper-towelling as a barrier before applying the plaster. This process may only be attempted where the wood is in good condition, but the advantage is the elimination of wrinkles on the mould-surface caused by the wet paper-towelling.