Mechanical properties of finger jointed beams fabricated from eight Malaysian hardwood species

Mechanical properties of finger joints made from eight Malaysian tropical hardwood species were investigated in this study. The wood species studied were merpauh (Swintonia spp.), kapur (Dryobalanops spp.), resak (Cotylelobium spp.), white meranti (Shorea spp.), bintangor (Calophyllum spp.), jelutong (Dyera spp.) sesendok (Endospermum spp.) and kelempayan (Neolamarckia cadamba). All of the selected wood species fell into strength group (SG) ranged from SG 4 to SG 7 as described in MS 544: Part 2. Effects of species, finger orientations (horizontal and vertical) and fingers lengths (15 mm and 25 mm) on mechanical properties of finger joints were evaluated. It was observed that bonding properties of low-density wood was better than high-density wood due to better wettability characteristics. Intimate bonding between wood and adhesive was found in low-density wood as its higher porosity promoted better resin penetration. Better joint efficiency was also observed in low-density wood. Finger joints made from longer finger (25 mm) generally exhibited better strength properties compared to shorter one. Samples that jointed vertically displayed superior properties in comparison to that of jointed horizontally. Non-destructive evaluation technique was found not suitable to estimate the static modulus of elasticity of the finger joints that fabricated in this study and further improvements is needed to obtain better result.