What is a wet Film Thickness Gauge?

A wet Film Thickness Gauge is a tool designed to measure the thickness of liquid coatings in an easier and faster way. It measures thickness immediately after a coating is applied to a material. Wet Film Thickness Gauges measure the thickness of almost all types of organic coatings such as:

• varnish
  

• paint
  

• coating
  

• resin
  

• gel coat

It can also be used to measure powder coating thickness before curing. Measure wet film thickness to determine correct dry coating thickness.

Wet Film Thickness Gauges are also known as wet film gauges, notch gauges, step gauges, and combs. Have notches or teeth machined into the side of the gauge. The endpoints of the gauges are used as references to each other. For a particular side, the two notches are the same size and act as a zero reference, which represents the substrate. The notch on the same side is shorter relative to the outer notch. These all represent different distances from the outer edge teeth corresponding to zero. The distance indicates the wet coating thickness surface that needs to be measured. The notches are marked in MILS, equivalent to 0.001 inches.

The wet Film Thickness Gauge needs to be placed at a 90-degree angle to the coating material and needs to be in full contact. Once the gauge is removed from the material, the depth is determined by the MIL of the largest notch wetted by paint and the smallest notch not wet. For example, if the maximum notch wet is 8 MILS and the minimum notch unwet is 10 MILS, you can say that the wet film thickness is 8 to 10 MILS.

For accurate measurements, the following regulations need to be observed:

• The wet film thickness needs to be measured immediately after the coating is applied.
  

• The meter needs to be used on a smooth, flat surface free of irregularities.
  

• Several measurements should be taken consecutively to obtain an average result.
  

• The meter should be cleaned with a soft cloth after use.