What does breaking strength mean?
Pull-off strength is a measure of the adhesion strength of a coating based on the pull-off test. The test consists of sticking the cart to the surface to be tested and pulling the cart away from the surface, perpendicular to the surface. Tensile strength is the result of this test and is based on the force used in the pull, the type of adhesive used with the dolly, and the type of failure of the coated surface.
The peel strength of the coating is an important consideration when selecting the appropriate coating to protect surfaces made of metal, plastic, wood, concrete and glass. Failure to test the adhesion of a coating system may increase the risk of coating delamination and exposure of underlying surfaces.
Experts explain the breaking strength
Even if the manufacturer's specifications for a particular paint system have the desired adhesion properties, factors in the application process can reduce the quality of the adhesion. Therefore, pull testing provides inexpensive insurance to determine whether a coating system will adhere as desired. The tensile strength tested is application dependent and can be configured by modifying components of the test equipment. The radius and surface area of the dolly or bonding probe can be modified to increase the maximum pull-off strength that can be tested. The dolly is glued to the surface to be tested with resin, usually epoxy.
While a convenient measurement, it is difficult to determine breaking strength in a consistent and accurate manner. As a result, there are few industry standards and wide variation between different spec sheets. Nonetheless, the proven cost importance of using peel strength adhesion assessment to prevent the repair of poorly adhered surface coatings in large-scale applications cannot be overstated.
