Graco wet film gauge

To be able to measure the thickness of a wet film of material, is very important for certain products such as intumescent which require a specific dry film thickness to deliver the specified time protection.  The relationship between the wet film thickness and the thickness of the same film when dry, is calulated from the percentage of solids in the wet material;  eg a 50% solids wet film will produce a dry film that is half the thickness when wet.

A wet film gauge is a plate typically 80 mm x 60 mm with a series of teeth of different lengths along each edge, with the ends of each side supported so that when pressed at right angles onto the film, some of the teeth will enter the film and some will not.  The tooth that is just touching the film surface indicates the thickness of the film.  This measurement must be done on a flat surface.