Properties of Finger jointed hardwood and softwood timber species in Sri Lanka.

Abstract

Finger joint is sustainable, ecofriendly and economically valuable concept for furniture industry. It ensures the sustainable utilization of small wood cut pieces which removed as waste. Finger joints are described as interlocking end joint formed by machining a number of similar tapered symmetrical fingers in the ends of timber members using a finger joint cutter and then bonded together. This study was conducted to determine the effect of flexural strength and compression strength of soft wood species (pine-Pinus Caribaea) and hard wood species (Mahogany- Swietenia macrophylla) mainly used two timber species in Sri Lanka. For these test, BS 373: 1957 and BS EN 15497:2014 were used as standards for tests. The test for mechanical properties were performed an Universal Testing Machine (UTM 100PC). The parameters were analyzed by using ANOVA and means were separated by Duncan’s Multiple Range Test at 0.05 significant level in SPSS. Pine and Mahogany finger jointed sections and comparing them with the clear specimens from the same wood lot. For joining the sections the Poly Vinyl Acetate was used as a bonding material. Vertical finger joint orientation and 13mm finger joint length were used in this study. It was found that MOR and MOE are affected by the finger jointed specimens and the clear specimens. The values of compression parallel to grain of Mahogany showed no significant difference between the values for the jointed and un-jointed specimens. But the values of compression parallel to grain of Pine showed a significant difference between the values for the jointed and un-jointed specimens. Considering the flexural test, Pine and mahogany clear specimens are in same strength group and finger jointed Pine and Mahogany specimens are belong to another group which is relatively low strength. However compression strength values of clear Pine specimens are relatively higher than Mahogany clear specimens.