The grinding methods include dry grinding, water grinding, oil grinding, wax grinding and toothpaste polishing. Dry grinding can be divided into rough grinding, flat grinding and fine grinding. Rough grinding is generally used to remove wood wool, scars, glue marks and pencil marks from wooden blank before Bai treatment, while flat grinding is usually used to grind the large plane with sand cloth and sandpaper wrapped with small wood blocks or hard rubber, so that the leveling effect is better, Fine grinding is generally used for putty, sealing paint, color matching and color filling after each intermediate treatment, sand grinding requires careful. Water mill is to use sandpaper dipped in water (or soapy water) grinding. Water grinding can reduce the wear marks, improve the smoothness of the coating, and save labor and sandpaper.
Sanding steps plays below three important roles:
No 1: Removal burrs, oily dirt on the surface of the substrate
No 2:For the surface of the putty scraped, the surface is generally rough and needs to be sanded to obtain a smoother surface, so sanding can reduce the surface roughness of the workpiece;
No 3:Enhance the adhesion of the coating. Before spraying a new paint film, it is generally necessary to polish the old paint film after hard drying. Because the coating has poor adhesion on an excessively smooth surface, the mechanical adhesion of the coating can be enhanced after polishing.
We have to choose the right grit based on different sanding steps as well as sanding requirements.Generally speaking, we can follow below instructions:
Solid Wood White Body : 180# Grit -----240# Grit sanding paper
Plywood or bottom layer primer sanding: 220# Grit -----240# Grit sanding paper
Second step for even primer : 320# Grit -----400# Grit sanding paper
Surface primer or finish paint :600# Grit -----800# Grit sanding paper
Polishing the finish paint : 1500# Grit -----2000# Grit sanding paper
Post time: Oct-10-2020