Stud-Pull-Off Adhesion Test

A coating adhesion test that uses a small stud whose head has a specific surface area and which is epoxy-glued to the coated surface. A machine then pulls the stud with increasing force until the stud pulls off. The measured force divided by the surface area then gives the coating adhesion. This technique is successful for measuring adhesion of paint and some platings. However, the adhesion of PVD coatings is generally stronger than the holding power of the glue to the coating. In fact, the adhesion of PVD coatings often exceeds the cohesion of the substrate material. Also, the PVD coatings are generally good non-stick surfaces, creating excellent release of the epoxy from the coating surface, further reducing the effective range of this type of measurement..