Impacts of impregnation with boric acid and borax on the red colour tone of some hardwoods and varnishes

Abstract

This study was performed to determine the impacts of impregnation with boric acid and borax on the red colour tone of some hardwoods and varnishes. For this purpose, the test specimens prepared from Oriental beech (

Fagus orientalis Lipsky) and European oak (Quercus petraea Liebl.) wood which met the requirements of ASTM D 358 are impregnated with boric acid and borax according to ASTM D 1413- 99 by vacuum technique. After impregnation, surfaces were coated by cellulosic, synthetic, polyurethane, water-borne, acrylic and acid hardening varnishes in accordance with ASTM D 3023 standards. The red colour tone values were determined according to ASTM D 2244 standards after varnishing. Depending on wood material types, the red colour tone value was highest in Oriental beech, synthetic and borax, whereas it was lowest in European oak, water-borne and boric acid. According to wood material + impregnation material + varnish interaction, the red colour tone value was highest in Oriental beech + boric acid + synthetic varnish, whereas it was lowest in European oak + boric acid + polyurethane varnish. Consequently, impregnation of wood material with boron compounds show decreasing impact on the red colour tone. This impact might be taken into consideration in the applications where red color tone values of hardwood are important.