EFFECTS OF LACQUER VISCOSITY IN WOOD FINISHING QUALITY

Wood finishing quality is affected a lot from the viscosity of the finishing material, especially during the alignment of the material into the wood surface. In wood finishing technique, lacquer viscosity is expressed by the time in seconds in which a certain volume of liquid leaks from a cup with a specific geometric form, passing through the calibrated open hole on the bottom. Measurement results are affected from the environment temperature. The viscosity measurements of finishing materials such as nitrolacque (nitrocellulose paint) and polyurethane were made at different temperatures, starting from 6oC ? 30oC. The measurements were made with FORD-4 cup. From observed data, when temperature is 20oC, the viscosity of nitrolacque (nitrocellulose paint) is 30 seconds, polyurethane viscosity is 25 seconds. At temperature 28 oC nitrolacque (nitrocellulose paint) viscosity became 20 seconds and polyurethane viscosity became 16 seconds. By lowering the temperature the viscosity increases. This should be taken in consideration to achieve good quality results from spraying finishing in different seasons of the year.