THE DRYING KINETICS OF PROTECTIVE COATINGS USED ON SAND MOLDS Received – Prispjelo: 2014-03-05

Investigation results of the drying rate of the selected protective coatings (water and alcohol) are presented in the article. Coating drying rate was determined for the first and second layers. The coating was applied to moulding sand cores. The rate of drying coatings were tested for three coating apparent viscosities estimated by means of the Ford 4 mm cup. Drying rates of the protective coating were examined by using the gravimetric technique and ultra-sonic technique. Measurements were carried out in a continuous way under controlled conditions: constant ambi-ent temperature and air humidity. Research shows that the drying time of the second coating layer is longer by 20 – 30 % than the first layer. Key words: foundry, molds, protective coatings, kinetics of drying, gravimetric technique, ultrasonic techniqu