4. Summary of Test Method
4.1 The organic coatings under test are applied to suitable
thin metal panels. After the coatings have cured, a standard
weight is dropped a distance so as to strike an indenter that
deforms the coating and the substrate. The indentation can be
either an intrusion or an extrusion. By gradually increasing the
distance the weight drops, the point at which failure usually
occurs can be determined. Films generally fail by cracking,
which is made more visible by the use of a magnifier, by the
application of a copper sulfate (CuSO4) solution on steel, or by
the use of a pin hole detector.