Paint thickness is an essential parameter that needs to be measured routinely. The proper film thickness has an impact on the paint opacity, appearance, and protective properties of the coating. Applying too much coating can also be detrimental that can lead to excessive drying time, cracking, and flaking of the paint film. Coating thickness measurement will monitor the paint process and maintain the appropriate coating properties.
Measuring the film thickness immediately after coating the surface is important to control the spreading rate and the final dry film thickness. Wet film thickness should be monitored frequently to maintain an efficient coating process. A wet film thickness gage is an inexpensive, easy to use device. They cover a wide wet film thickness range from industrial maintenance applications to thin coil coatings. Wet film gages can be used on virtually every substrate.
Paint thickness gauges for dry film thickness can either be a non-destructive measurement or destructive measurement. The non-destructive paint gauge uses measurement principle of magnetic induction for ferrous substrates and eddy-current for non-ferrous substrates.
The generally accepted ratio of dry film to wet film thickness of most coatings is:
Wet Film x % Volatile Solids of Coating
Dry film = ————————————————