1. An Introduction to Pull-Off Adhesion on Coated Surfaces

When a coating is applied in the wrong climatic conditions, or to a poorly prepared surface; there is a much greater chance that the coating will blister, delaminate or simply not stick to the substrate.

To test how well a coating adheres to a surface, adhesion testers are used:

  • Cross hatch; such as the Elcometer 107 or 1542, where a cutter with 6 or 11 blades is used to cut two sets of lines at right angles - the resultant debris is removed using either adhesive tape, a brush, or compressed air, and the results determined by the use of tables.
  • Push off adhesion testers, such as the Elcometer 108 and 508, have a pin which goes through the centre of a dolly that has been glued to the coated substrate, and pushes it off the coating, with the force recorded - ideal for convex and concave surfaces.
  • The pull-off adhesion test, the most commonly used method, where a dolly is adhered to the coated substrate, pulled off, and the resultant force recorded.

Elcometer offer three different pull-off adhesion testers. The original Elcometer 106, which is a hand operated mechanical gauge; the hydraulic Elcometer 506, with a separate, low height actuator and range of skirts for thick and thin substrates; and finally the Elcometer 510, which is similar in operation to the Elcometer 506 but, rather than manually, automatically applies the increasing force at a predefined and uniform rate, storing all of the results into memory by the simple press of a button.

This video is part of a series on Pull-Off Adhesion Testing, to see the next video please click here.

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