This method is designed to test the pull-of strength, also referred to as ‘adhesion’, of:
- coating on rigid substrates such as metal, VTR or wood;
- skin to core in sandwich panels.
The test is used to determine the maximum tensional force that can be applied perpendicular to a sample of fixed surface area (either 20 or 50 mm) before a plug of material is detached. Alternatively, the test can simply be used to determine whether a given surface remains intact under a prescribed tensional force (pass/failure). During the experiment, failure will occur along the weakest plane within the system consisting of the test fixture, adhesive, coating system, and substrate.
This test is performed with portable pull-off adhesion testers, which are capable of applying a concentric load and counter load to a single surface. Therefore, coating or skin adhesion can be tested even though only one side of the structure is accessible.
NOTE: this is a destructive test. Therefore, spot repairs may be necessary.