Wood Bending by Vapour Phase Ammonia Plasticization

Abstract

Trials with vapour phase ammonia plasticization of air-dried timber have indicated that species like Acrocarpus fraxinifolius, which are not amenable to steam bending, can be bent reasonably successfully and species like Mangifera indica, which respond to some extent to steam bending, can be bent to sharper curvatures by this technique. 13 mm strips of Grevillea robusta needed only 1 hr treatment at 5 kg/cm² pressure to bend to a radius of 37 mm (R/T = 3) while Acrocarpus fraxinifolitius and Mangifera indica needed 3 hr treatment to achieve the same result. A higher wood moisture content at the time of treatment appeared 10 improve the rate and degree of plasticization and the bending behaviour. Further trials are proposed to produce bent wood furniture items using this technique.