Microwave Surface Modification of Pinus radiata Peeler Cores: Technical and Cost Analyses

Abstract

Radiata pine (Pinus radiata) peeler cores are classified as a by-product of plywood manufacture and have the potential for development as value-added solid wood products. This article outlines technical and cost analyses of microwave surface modification of radiata pine peeler cores along with the methodology, including measurements of temperature distribution and of preservative uptake and distribution following microwave heating. After microwave treatment, the highest temperatures are observed on the surfaces of the peeler cores. A gradual decrease in temperature is noted with depth within the timber. Chromated copper arsenate uptake after pressure impregnation ranges between 94 and 314 liters/m 3 . This uptake is three to nine times higher than that of control timber (no microwave treatment). Cost analyses focus on the microwave treatment of peeler cores and indicate that microwave modification costs range from US$0.95 to US$1.23 for one peeler core (i.e., US$29 to US$37 per m 3 ), depending upon electricity charges and the number of working shifts employed.