Study of effect of Grit size on Contact Angle Surface of Kelempayan (Neolamarckiu cadamba) and Petai (Parkia speciosa) wood

Neolamarckia cadamba is also known as ‘kelempayan’ is a fast growing tree species and one of the quality of raw materials for plywood as well as pulp and paper industry. Parkia speciosa or also known as ‘petai’is commonly found in Malaysia and used locally for temporary light construction, furniture and also interior finishing. The major problem statement are to find the effectiveness use of sandpaper grit size on wood species before and after wood planing and to obtain better understanding on wood characteristic parameter. The objective on this research is to evaluate and determine the effect of the grit size on the quality of sanded surface of Neolamarckia cadamba and Parkia speciosa, and also to determine contact angle and to assess surface quality using 3 different liquid. Both wood species was collected from Universiti Malaysia Kelantan’s area. Neolamarckia cadamba and Parkia speciosa wood surfaces were evaluated in specimens that had been sanded using silicon carbide sandpaper, 3 methods of sanding were used with 3 grit size; a) single stage 100-grit, b) two stage l00+l 50-grit, and c) three stage with l00+l50+l80-grit. SEM analysis was carried out for every grit size sanded sample of both species. A total of 72 samples of solid Neolamarckia cadamba and Parkia speciosa wood species have been used in this study, each board was crosscut into 3 matches sections of 200mm length, the sections have been machine at 100mm of width and freshly planned to a thickness of 15mm. The sanding process has been done 30 times on each surface with a constant force. The measurements are carrying out with a view parallel to the grain. Meanwhile, for water, oil and formamide medias of both species showed that the surface sanded with [l00+l50+180-grit has lower mean value which were for Neolamarkia cadamba (34.746, 25.025 and 0.094) and Parkia speciosa (34.88, 25.799 and 0.048). The smoother surface was more wettable and absorbent compared to the rougher surface. Based on present study, sanding has a significant effect on the wettability, surface roughness, and surface absorption of the wood surface which could provide useful information on the bonding and finishing of wood industry.