This study investigated the dimensional stability and mechanical properties of thermo-mechanically compressed radiata pine (Pinus radiata) wood followed by oil heat-treatment. Wood specimens were first compressed in the radial direction then heat-treated in a linseed oil bath at 160 to 210˚C. Spring-back percentage, water repellence efficiencies and compression set recovery percentage were determined to examine the dimensional stability. The resistance of treated wood against a brown rot fungi was assessed from an accelerated laboratory fungal decay test. Strength, stiffness and hardness were determined and effect of different treatments was analysed.

After thermo-mechanical compression of wood, high compression set (39%) was achieved without any surface checks and cracks. Specimens with thermo-mechanical compression followed by oil heat-treatment showed relatively less swelling and low compression set recovery in high moisture conditions. The fungal resistance of wood after the combined treatment of thermo-compression and oil heat-treatment also increased compared to untreated wood and wood treated using thermo-compression only. The mechanical properties of wood from combined thermo-mechanical compression and hot oil treatment were less than those of wood from “compressed only” but were still significantly better than those of the untreated wood.