How to measure film thickness with comb gauge?

Scope and description

This method is suitable for wet film thickness measurements during field painting operations. Measurements give a rough indication of wet film thickness.

Instruments and Materials

Comb Gauge: It is made of metal or plastic thin plate, and the periphery is composed of comb teeth. The outer teeth at both ends are on the same horizontal plane, forming a baseline, and the middle inner teeth have different gaps from the horizontal plane. Layer thickness value, as shown in the figure below.

test methods

During the test, press the comb gauge vertically and firmly on the surface of the coating film to be tested, some of the teeth are wetted, remove the comb gauge, check the tooth gap, determine the shortest tooth that is in contact with the wet film surface, and finally touch the The value between the wet film tooth and the scale indicated for the first untouched wet film tooth is recorded as the wet film thickness.

The result shows

The reading between the last wetted tooth and the unwetted tooth is the measured wet paint film thickness, expressed in μm. Take at least two additional readings in different locations in the same manner to obtain representative results for the painted area.

Reference standard

National standard GB/T 13452.2 "Determination of paint film thickness of paints and varnishes".