How to measure wet film thickness using the Elcometer Wet Film Combs

Wet film thickness measurement provides an indication of the quality of the applied coating. A wet film comb, also known as a wet film thickness gauge, measures wet film thickness.

The Elcometer Wet Film Combs are easy to use and are available in a variety of scales, ranging from 20µm to 3000µm and a variety of materials, including: stainless steel, aluminium and plastic to meet different film thickness needs.

Why measure wet film thickness

Wet film thickness measurement is an excellent quality control measure, which is easy to carry out and analyse. Wet film thickness measurement provides instant feedback on the quality of the film applied and allows corrections to be made while the application is proceeding.

By measuring the wet film thickness, it is possible to predict the dry film thickness. The dry film thickness can be calculated using the ‘solids to liquids’ ratio, also known as the volume solids content. For example: if the paint has a volume solids value of 80% and the wet film thickness is 200 µm, the dry film thickness will be 160 µm (200 µm x 80% = 160 µm).

How to measure wet film thickness using a wet film comb

Place a wet film comb down on the surface under test, positioning the comb perpendicular to the substrate. Hold the wet film comb in position and wait a few seconds until the teeth are wet. Remove the comb from the film. The wet film thickness lies between the biggest value ‘coated’ or ‘wet’ tooth and the smallest value ‘uncoated’ or ‘dry’ tooth.

Elcometer range of Wet Film Combs include:

  • Hexagonal Wet Film Combs – six sided wet film combs available with scales ranging from 25µm to 3000µm
  • Stainless Steel Wet Film Combs – reusable stainless steel combs available as either metric or imperial combs with thickness ranges up to 1250µm or 50mils
  • Long Edge Wet Film Combs - stainless steel wet film combs are wire eroded to provide an accuracy of ±2.5µm (0.01mil) and are supplied with either Metric or Imperial wet film thickness measurements
  • Plastic Wet Film Combs - made from ABS plastic, they are ideal for a single use to be kept as a record of wet film thickness measurement

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