Pencil hardness, a simple test, can also be used to measure the hardness of the coating, or to measure the scratch resistance of the coating. Although some people may think it is a low technology, it is still the mainstream use method for many coating manufacturers and some finishing workshops to determine the hardness by scraping the coating with special pencils of different hardness. In addition, this method is also used to determine the degree of curing of these coatings, especially when heat is used for intensive drying.

Sharpen the pencil to expose 4-6 mm, so that its end face is flat and the edge is sharp. Place the coating sample on a horizontal surface. Hold the pencil so that it is 45 degrees away from the sample surface (the tip of the pencil is far away from the operator), and then draw a 6.5 mm line away from the operator. Start with the hardest pencil and reduce the hardness of the pencil in turn until any of the following occurs. First, the pencil will not cut into the coating, or scratch the coating (pencil hardness); Second, the pencil will not scratch the coating (scratch hardness). Then, the pencil hardness is the pencil hardness of the coating to be tested.


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