Reason: Mixing ratio stated by the manufacturing company is not obeyed for two component paints; ambient temperature is very low; wood or ambient is very moist; a very thick application is carried out; above all, product or system is not well known in terms of suitability for sanding.
Solution: Before application, mixing ratios should be performed properly, application should not be performed in excessively moist or cold conditions and the application should not be very thick. Regarding the selection of system and brand, since drying time is long as curing occurs with chemical reaction in Polyurethane and Acrylic systems, it should also be noticed that these systems become suitable for sanding after time has elapsed. The sanding time is 6-8 hours in the summer, 24-72 hours in the winter. Those which dry earlier than those times which are normal for the chemical structure, probably contain modified resin. However, the time needed for the original Polyurethane or Acrylic varnish or paint to become suitable for sanding may be shortened by heating.