Ascertaining the quality of the adhesion of products like varnish, paint, glue, etc. is necessary to ensure that the coating of the substrate should be done suitably and appropriately.
To measure the same, a large number of adhesion testing methods are available that helps to analyze that how efficiently the coating or painting is done on the substrate. In Paint Industries, paint adhesion tester is usually done to analyze whether the coating is done on the substrate properly on not. To perform the same, various adhesion test procedures and standards are introduced by the standardization authorities namely, Scrape Adhesion Test, Pull-off test, cross hatch test and many more.
Cross Hatch Test
Cross Hatch Tester is a method which is used to determine the resistance of the paints to separation from any material when cross hatch instrument is used over the surface of the material that creates a right angle lattice pattern on the painting and pierce the material. This test helps to determine the quality of the adhesion of the paints. To test the quality of the metal substrate with multiple coating, ascertain the resistance of the coating to separation of the layer of the paint from the substrate when the paint is scratched from the surface of the substrate with the help of Cross Hatch Tester.
As per ASTM standard test methods, this test can be performed in two manners i.e. Method A and Method B. According to Method A, a cut is made on the painted metal substrate using the blades. Now paste a pressure sensitive tape on the substrate. Now remove the tape rapidly from the material and measure the strength of the material using 0 – 5 measurement scale.
To test the quality of the Paint adhesion using Method B made a cross hatch pattern on the substrate. Now remove the coating using a soft brush. Now take the readings with the help of 0-5 measurement scale. On the 0-5 measurement scale, 0 means 65% area is removed, and the quality of the adhesion of the paint is not good whereas 5 means 0% paint is removed, and the adhesion strength of the paint is best in quality.
Scrape Adhesion Test
The Scrape Adhesion test is also used in pain industries to measure the adhesion strength of the coatings when applied to the flat and smooth surface. This test method is used to provide a competent rating to a high number of coated surfaces that shows major variation in the adhesion.
The adhesion of the paints can also be determined by measuring the minimum amount of tension which is required to crack the coating which is done on the substrate. This test is quite different from other test methods. Hence, the outputs of this test can’t be compared with other test methods.