This document specifies three methods for determining the adhesion by carrying out a pull-off test on a single coating or a multi-coat system of paint, varnish or related product.
These methods include:
— method A: using two dollies, suitable for testing both rigid and deformable substrates;
— method B: testing from one side only, using a single dolly, suitable for rigid substrates only;
— method C: using dollies, one as a painted substrate.
These test methods have been found useful in comparing the adhesion behaviour of different coatings. It is most useful in providing relative ratings for a series of coated panels exhibiting significant differences in adhesion.
The test can be applied using a wide range of substrates. Different procedures are given according to whether the substrate is deformable, e.g. thin metal, plastics and wood, or rigid, e.g. thick concrete and metal plates. To avoid distortion of the substrate during the tensile test, it is common to use a sandwich construction. For example, for special purposes, the coating can be applied directly to the face of a test dolly.