Cupping testers are employed in the testing of the elongation and deformability of lacquers and protective coatings applied to metal substrates.
The cupping tester operates by using a punch to push upon the unpainted side of a coated panel until the painted side shows signs of deformation (cracks) in the coating.
However, generally they consist of a solid metal base which forms a circle over which the coating is tested.
There is a punch that will go up to and through this metal hole in order to apply pressure to the coating and substrate.
In addition to these core components, there is usually an included magnifier which helps to determine the point of major deformation.