How to determine the coating thickness of wet film?

In paint engineering, it is often necessary to measure the wet film thickness of the coating. There is a prerequisite for the measurement of wet film thickness, which needs to be measured immediately after the paint film is prepared, otherwise it will be caused by solvent volatility and water evaporation. The curing shrinkage of the film layer is not to measure the wet film thickness at that time, and it may become the dry film thickness accidentally. Therefore, how to measure the wet film thickness of the coating is particularly important. The national standard GB/T 13452.2-92 mentions that one method is to use wet Film Thickness Gauge (comb gauge) or wet film wheel (wheel gauge), while the old American ASTM D1212-79 stipulates that wet Film Thickness Gauge (comb gauge ) ) and Pfund wet film meter to measure the wet film thickness. Specifically: