TREATABILITY OF WESTERN SOFTWOOD AND RED ALDER SHAKES

The potential to develop durable shakes from several western tree spec ies, other than western redcedar, is being explored, Results of trials with several different waterborne and oilborne preservatives are disc ussed in this paper. Penetration of preservative through the entire th ickness of shakes was achieved with a variety of waterborne and oilbor ne systems, but the distribution of the preservatives within the shake s was influenced by preservative formulation and concentration and by treating cycles. For active ingredients used in both waterborne and oi lborne formulations, more uniform patterns of preservative distributio n generally occurred with the oilborne formulation. With preservatives applied only as waterborne systems, uniformity of distribution was so metimes enhanced by increasing concentrations of the treating solution . With alkaline waterborne systems, uniformity was further enhanced wi th a stepwise application of pressure and a lengthy pressure period.