Effects of boron formulation on specific timber types used in ships of historical importance
B King, G M Smith, J W Palfreyman, S McCutcheon
This paper reports results of preservative treatment and leaching experiments, using borax, polybor and boracol 20, on small wood blocks of English oak and American pitch pine heartwood. Earlier experiments on the performance of various biocides as possible additives to bilgewater to prevent fungal decay of shipping timbers had suggested that some formulations of boron might be associated with physical changes to specific types of timber. Since samples of oak and pitch pine were to be supplied for remedial work on the historic ship RRS Discovery it became important to investigate more critically the effects of boron on such timbers. Variable factors investigated in this study included temperature, sample type, soaking time in preservative and time of leaching. Weight changes and dimensional changes were measured. Preliminary results indicate that there was little effect, at 10°C, on block weight or dimension. Some changes were found at 45°C indicating that the results obtained in earlier experiments may be unrepresentative of those which might be obtained when the biocide is used under service conditions.