Effects of machining method and grain orientation on the bonding strength of some wood species

This study was conducted to determine the effects of various machining methods and grain orientation on bonding strength of some wood species. For this purpose, Oriental beech (Fagus orientalis Lipsky.), Oak (Quercus robur), Scotch pine (Pinus sylvestris L.), Poplar (Populus tremula L.) and Uludag fir (Abies bornmülleriana Matff.) were used as raw materials. Phenol–formaldehyde (PF), poly (vinyl-acetate) (PVAc), polyurethane based Desmodur-VTKA (D-VTKA) and urea–formaldehyde (UF) adhesives were applied to one surface of the test samples. Bonding strength tests (based on TS EN 205) were applied on the connection surface. The test samples were machined with circular saw, band saw and thickness planer. The results indicated that the highest bonding strength was obtained from Oriental beech wood samples bonded with PVAc adhesive (14.83 N/mm2), while Poplar samples bonded with D-VTKA had the lowest values (2.99 N/mm2). In addition, the machined surface of the tangential direction had higher bonding strength than that of the radial direction.