How impregnation with boron compounds affects the surface hardness of some varnishes

Abstract

Purpose

The purpose of this paper is to investigate how impregnation with boron compounds affects the surface hardness of varnished wood materials.

Design/methodology/approach

Test samples were prepared from Scotch pine, Oriental spruce, and Uludag fir, which met the requirements of ASTM D 358.These samples were impregnated with boric acid (Ba) and borax (Bx) using a vacuum technique, according to ASTM D 1413 guidelines. After impregnation, surfaces were coated with cellulosic, synthetic, polyurethane, water‐based, acrylic, and acid‐hardening varnishes in accordance with ASTM D 3023 guidelines. Surface hardnesses of specimens after the varnishing process were determined, in accordance with ASTM D 4366 guidelines.

Findings

Surface hardness was greatest for samples of spruce treated with Ba and polyurethane varnish, and lowest for samples of Scotch pine treated with Bx and synthetic varnish. With regard to wood type, impregnation material, and varnish type, surface hardness was greatest for Oriental spruce impregnated with Ba and polyurethane varnish and lowest for Scotch pine impregnated with Ba and synthetic varnish. Thus, impregnation with boron compounds increased the surface hardness of the varnished wood.

Research limitations/implications

A protective coating (such as varnish) has limited resistance to external effects and the lifetime of the coating will be determined by the type and severity of conditions to which it is exposed.

Practical implications

Types of varnishes, wood materials, and impregnation chemicals affect surface hardness and can influence the usefulness of wood materials, where surface hardness values are important.

Originality/value

The study results reported in the paper help address the lack of research in this field and should be informative, in particular, for manufacturers and consumers in the furniture and decoration sector.

Citation

Atar, M., Keskin, H., Korkut, S. and Korkut, D.S. (2011), "How impregnation with boron compounds affects the surface hardness of some varnishes", Pigment & Resin Technology, Vol. 40 No. 4, pp. 229-234. https://doi.org/10.1108/03699421111147290