Qualificação da superfície acabada em madeira de Eucalyptus grandis W. Hill ex Maiden, Toona ciliata M. Roemer e Coffea arabica L.

Abstract

The finishing is intended to improve the aesthetics of a wood machined. It also guarantee a durability of wood products. The quality of the coating is related with the anchored surface and product used. Normally, surface of quality should have low roughness, few defects and absence of impurities. The objective of this work was to evaluate the behavior of the wood of Eucalyptus grandis, Toona ciliata and Coffea arabica subjected to finishing with nitrocellulose varnish. Samples were dried (12%), planed, sanded (grain of 100-150-220) and received sealer and varnish. Next, the surface qualifications were assessed by adhesion, brightness (Glossmeter), abrasiveness (abrasimeter), hardness and dry layer thickness (ultrasound). Brightness and abrasiveness tests showed no statistical difference among the varnished wood. The highest hardness value was found in the varnish applied over the wood of Eucalyptus grandis (298 g). The lowest dry layer thickness value was found in the varnish applied over the wood of Coffea Arabica (55.37 μm). The nitrocellulose varnish showed good performance in terms of adherence, without occurrence of detachment at the intersection of the varnish and detachment lower than 1 mm along the incisions in all woods.