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