Coatings tightness test in accordance with ISO 29601
The tightness of the coatings is evaluated to verify the corrosion protection of the paint system used on a metal substrate. It consists in assessing the porosity of the hardened coatings. It allows you to verify the quality of coatings, or to detect production errors resulting from the application of paint products, e.g., undercoat contamination, pinholes (craters), cavities, cracks, and other discontinuities in the structure. Very often, defects cannot be revealed during visual inspection. For this purpose, a high or low voltage detector is used. The type of device and voltage are selected depending on the thickness of the non-conductive layer of the coating system. The defects reduce the dielectric strength of the coating, which allows them to be detected. During the test, the device generates a sound signal in the places where there are discontinuities. The test report specifies the number of defects found and the locations of their detection.