It is helpful in giving relative ratings for a number of coated panels showing significant differences in adhesion.
When the materials have dried, the adhesion is determined by pressing panels under a rounded stylus loaded with increasing weight until the coating is removed from the substrate surface.
The force that is applied gradually increases and is monitored until a plug of coating is detached or a previously specified value is reached.
When testing a multi-coat system, determination of the resistance to separating different layers from one another can be accomplished.
There are two methods described in the ASTM Specification;[4] An X-cut is made through the film with a carbide tip tool to the substrate.