Water resistance of natural joint of spruce produced by linear friction welding without any treatment

Abstract

This research work showed that spruce wood can be butt welded in a short time end-grain to-end-grain without any treatment. Wood welding has already been shown to be well adapted to the manufacture of wood structures of larger dimensions. When pressure increased, the welded material formed is of higher density and consequently the water resistance improved. The welded spruce samples present a much improved water resistance when the welding pressure was increased from 2.75 MPa to 3.75 MPa for the same welding time of 6 s. The welded interphase in end-grain-to-end-grain butt welding of spruce appears to occur by the formation of an interphase having the appearance of finger-joints. This is due to the different behaviours of the late and early wood rings of spruce during welding. This, by increasing the surface of contact, is shown to improve the water resistance of the original butt joint.