Effects of Ash (Fraxinus exelsior L.) Veneer Surface Form and Spray Gun Inclination Angle on Color and Gloss Values of Polyurethane Coatings

In this study, polyurethane paint and varnish were applied to the surfaces of test samples prepared from ash (Fraxinus exelsior L.) veneer with different surface forms at 45° and 90° angles. The objective was to determine the changes in gloss and color values resulting from the application of these polyurethane coatings. In order to achieve this objective, samples were prepared by bonding ash veneer with two different surface characteristics (smooth and band sawn) onto MDF, and these were selected as test samples. Polyurethane paint-varnishes were applied to test sample surfaces and the resulting changes in gloss and total color (∆E) were evaluated following accelerated UV ageing. The methodology employed for the UV ageing tests, gloss tests and color tests applied to the test samples was in accordance with the relevant standards. The findings of the research indicate that the type of protective layer and veneer surface form are effective factors influencing gloss and ΔE values. The gloss values were found to be high in varnishes applied to smooth veneer surfaces, while the total color change values were determined to be low in protective layers applied to traced veneer.