Bond durability of wood-glue joints on Kapur (Dryobalanops spp.) and Yellow Seraya (Shorea spp.) bonded with phenol-formaldehyde resin adhesive

Bond durability of wood-glue joints on Kapur (Dryobalanops spp.) and Yellow Seraya (Shorea spp.) bonded with phenol formaldehyde resin was investigated. The tensile shear strength of wood-glue joints bonded and tested thirteen years ago were compared with samples tested after thirteen years conditioning. The effect of treating wood (boiling for two to thirtytwo hours) on the tensile shear strength of the wood-glue joint was also taken into consideration. The tensile shear strength of Kapur and Yellow Seraya treated for 20–24 and 15–20 h, respectively, before gluing was higher than that of the untreated samples which were bonded and tested thirteen years ago. The retention ratio of tensile shear strength of Kapur after 13 years was lowest at 20–24 h boiling. Likewise, results for specimens similarly tested showed the same pattern for both dry and wet conditions. However, variation of boiling time on the solid wood of both raw materials did not affect their ratios of decrease in tensile shear strength. Bond durability of Yellow Seraya wood-glue joints was higher thanthat for Kapur wood-glue joints as indicated by the higher retention ratio of the tensile shear strength of the former compared with the latter.