FOREST PRODUCTS JOURNAL, vol.59, no.6, pp.90-94, 2009 (SCI-Expanded)
The objective of this study was to evaluate the effect of surface roughness and species on adhesion strength between wood and two types of finishes. Samples from four species, Scotch pine (Pinus sylvestris), spruce (Picea orientalis), beech (Fagus orientalis), and chestnut (Castanea sativa) were used for the experiments. Chestnut samples showed the roughest surface. Beech samples had the smoothest surfaces which resulted in the highest adhesion strength values when they were coated with cellulosic varnish as well as polyurethane lacquer. It seems that the diffuse porous anatomical structure of beech along with its high density of 0.68 g/cm(3) could be responsible for its higher adhesion strength than the other three species evaluated. Overall both roughness and adhesion strength values of the four species were adversely affected when their equilibrium moisture content increased from 7.5 to 14.5 percent. Results of statistical analysis showed that samples coated with cellulosic varnish had significantly higher adhesion strength than those coated with polyurethane lacquer.