Sanding properties of several lesser-used timber species in Ghana

Sanding qualities of seven lesser-used timber species and two primary species used as control were investigated at 12% and 20% moisture contents using four grit sizes of sandpaper on two machine sanders. The species were extracted from three ecological zones of Ghana. Samples were prepared in accordance with American Society for Testing and Materials Standards (ASTM) D143-94 (2007) and ASTM D1666-87 (2004). The results of the chipping tendencies showed that the belt sanding machine with both grit sizes 60 and 80 performed better than the drum sander for all the species. Sandpaper of grit size 60 recorded higher percentages of defect-free samples, ranging between 74% and 95%, for the species investigated than sandpaper of grit size 80 which ranged between 33% and 68%. The surface quality of the chipped grain samples that were sanded at 20% moisture content to eliminate the chipped/torn defect was better than at 12%. The results of tests on fuzzing and scratching tendencies indicated that the performance of the belt sander was better than the drum sander. Higher percentages of fuzzy-free samples were obtained at 12% moisture content with grit sizes 100 and 120 but lower percentages of scratch-free samples were recorded at 20% moisture content. Also, sandpaper with grit size 100 had more pronounced fuzzy and scratchy defects on the wood species than with grit size 120. Generally, the texture and the density of the species had influence on their sanding qualities. On average, the sanding qualities of the medium and high density species of each of the lesser-used timber species studied were comparable to Milicia excelsa while Rhodognaphalon brevicuspe (low density species) was also comparable to Triplochiton scleroxylon.