This study was performed to determine the impact of impregnation with boron compounds on the surface hardness of varnished wood materials. For this purpose, test specimens prepared from Oriental beech (Fagus orientalis Lipsky) and oak (Quercits petreae Lipsky), which met the requirements of ASTM D 358, were impregnated according to ASTM D 1413 with boric acid and borax by a vacuum technique. After impregnation, the surfaces were coated by cellulosic, synthetic, polyurethane, waterborne, acrylic, and acid hardening varnishes in accordance with ASTM D 3023. The surface hardness of the specimens after the varnishing process was determined in accordance with ASTM D 4366. According to the wood type, impregnation material, and varnish type, the surface hardness was highest for the oak impregnated with borax and acrylic varnish and lowest for the oak impregnated with borax and synthetic varnish. Therefore, impregnation with boron compounds showed an increasing impact on the surface hardness of the varnished wood. (c) 2007 Wiley Periodicals, Inc.