BS EN ISO 1520:2006 Paints and varnishes - Cupping test

This International Standard specifies an empirical method for assessing the resistance of a coating of paint,varnish or related product to cracking and/or detachment from a metal substrate when subjected to gradual deformation by indentation under standard conditions (see 7.1).
For a multi-coat system, each coat may be tested separately or the complete system may be tested.
The method may be carried out as follows:
— either as a “pass/fail” test, by testing to a specified depth of indentation to assess compliance with a particular requirement;
— or by gradually increasing the depth of indentation to determine the minimum depth at which the coating cracks and/or becomes detached from the substrate.