Color and gloss evaluation in decorative stain applied to cases of Pinus radiata wood treated with copper azole micronized Type C
Six treatments (one control and five decoration coatings) were applied to radiata pine wood treated with micronized copper azole for outdoor use at a rate of 3,08 kg/m3 retention. One decoration coating was applied prior to impregnation, prestain and two decoration coatings were applied in a mixture with the micronized copper azole preservative Black Cylinder and Red Cylinder. The following two varnishes were tested: a water-based varnish and a solvent-based varnish.Additionally, untreated radiata pine specimens were tested as a reference. The changes in the gloss and color of these five decorative coatings were evaluated after undergoing natural aging tests for three months and accelerated aging trials during exposure to ultra-violet radiation of 340 nm for 500 hours. In the accelerated aging trials treatments, changes in gloss and color showed the lowest variations in treatment trials prestain and Black Cylinder and the highest variations in treatment trial Red Cylinder. In the aging tests trials, changes in gloss and color showed the lowest variations in treatment trials prestain and Black Cylinder. The costs of each decorative coating were assessed in terms of performance according to timber volume coated. The lowest cost of the three decoration treatments was prestain, with a value of 16 US$/m3, followed by Black Cylinder with a value of 24 US$/m3. Compared with the alternative siding products available in the market, such as fiber cement and vinyl siding, colored wood treated with prestain is competitive with vinyl siding, with 58% lower costs than fiber-cement.