Coating hardness testers are instruments fit to measure the resistance of a coating to mechanical stress, such as pressure, rubbing or scratching.
Pencil hardness tester is particularly suitable for quick evaluations of finished products. Pencil test expects that several pencils with different hardness are scrolled on the painted surface, to determine which leave an imprint. This method can be used only on smooth surfaces.
Coating hardness tester, called Bucholz, is employed to test coatings with characteristics of plastic deformation. The indentation method is not suitable for measuring the deformation characteristics of an elastic coating, because after the instrument removal shows no trace of indentation, or a minimal jag.
On the other hand, paint film bend tester is employed to determine the coating track resistance, or the stripping performance, by bending the sample around interchangeable cylindrical shafts.