Effect Of Grit Size On Contact Angle Surface Of Rubberwood (Hevea brasiliensis) And Sungkai (Peronema canescens)

Rubberwood (Hevea brasiliensis) and Sungkai (Peronema canescens) can be categorized as moderately strong wood and it is suitable for manufacture of furniture. The problem statement that found in this study were the effectiveness of sandpaper grit size on the surface of Rubberwood and Sungkai and also which of the grit size can give the best result to the wood during gluing process. The objectives of this research were to identify and compared the contact angle surface quality by using three different liquid that are water, oil and formamide and to identify the sanding traces on the surface of Rubberwood and Sungkai by using the Scanning Electron Microscopy (SEM) analysis. Rubberwood and Sungkai wood surface were evaluated in specimen that had been sanded using silicon carbide sandpaper, three methods of sanding were used with 3 grit sizes; a) single stage 120 grit, b) two stage 120-150 and c) third stage with grit sizes 120-150-180. A total of 72 samples of solid Rubberwood and Sungkai with dimensions 20cm x 10cm x 1.5cm have been used in this research. The sanding process has been done 30 times. The comparison of the contact angle for both species showed that most of the factors which were species and grit size. The suitable stage of water liquid test for Rubberwood was at three stage (74.485) while for Sungkai was at two stage (84.088). Oil liquid test showed that the suitable stage for Rubberwood was at three stage (54.542) and Sungkai was at single stage (65.871) while the formamide liquid test showed that the best contact angle for Rubberwood was at single stage (3.364) and Sungkai at three stage (3.502). In this research, third stage, 120;-150;-180; grit size is the suitable stage as rule sanding that can reduce the roughness value contact angle start from 120; and then to 180; because 150; does not effect as 150; and 180; were from same class. For SEM analysis, both species showed surface sanded with 120; much smoother. Based on this research, the smoother surface was more wettable and absorbent compared to rougher surface. This will help during finishing and gluing process in furniture industry.