This research study examined the influence of different adhesives (polyvinyl acetate and b-isocyanate adhesives) on finger jointed beams (5mm and 10 mm finger length) and scarf jointed beams (with various joint angles of 60⁰,70⁰and 75⁰), using longitudinal vibration method. According to the international standard of ISO 3129, 50 clear samples of oak wood without any visible defects (knots, cracks, decay) with the nominal dimension of 2×2×36cm (R×T×L) were examined. The acoustical properties of the samples (clear and sound samples and the jointed ones) before and after the joint implementation were evaluated. The results showed that the acoustic coefficient of finger jointed samples (10 mm finger joints) were much considerable than 5mm samples; moreover, the acoustic coefficient of finger jointed samples glued with polyvinyl acetate were considerably higher than those covered with isocyanate adhesive. In scarf jointed samples, the acoustic coefficient increased, gluing the joints with polyvinyl acetate rather than isocyanate adhesive. An increasing trend of acoustic coefficient was observed as cutting angles increased (from 60⁰ to 75⁰). It is concluded that polyvinyl acetate adhesive increases the acoustic coefficient compared with isocyanate adhesive.
Keywords: finger joint, scarf joint, adhesive, vibration method, acoustic coefficient
Authors
Yavari A.
Department of Wood and Paper Science and Technology, College of agriculture and natural resources, Science and research branch, Islamic Azad University, Tehran–Iran
Roohnia M.
Department of Wood Science and Technology, Karaj Branch, Islamic Azad University, Karaj, Iran
Kohantorabi M.
Department of Wood and Paper Science and Technology, College of agriculture and natural resources, Science and research branch, Islamic Azad University, Tehran–Iran
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