Take care of your coating thickness gauge.

Coating thickness gauges are widely used control tools among applicators and inspectors. With a little care and maintenance, these mechanical and electronic instruments can provide quality service for many years.

Don't wait for calibration

Before first use, and occasionally afterwards, it is always a good idea to read the owner's manual again to familiarize yourself with the features and capabilities of the instrument. Note the model, serial number, date of purchase inside the owner's manual, and highlight maintenance and calibration tips.

At this point, it is a good time to set a calibration interval. Calibration consists of measuring shims of known thicknesses and verifying that these results are within tolerances. How often your meter should be checked depends on many factors, such as frequency of use; the type of application, the care taken during use, handling or storage.

If you are someone who uses a thickness gauge regularly and you measure on rough surfaces and handle the gauge abruptly, it may be a good idea to choose a shorter calibration interval for your gauge. Choose a longer interval if your meter is used less regularly. If in doubt, start with a calibration interval of one year from the date of calibration, date of purchase, or date received. What should you do at these intervals? It depends on your established quality system. Some users just measure a sample when the measurer is new and notes the measurement. This sample is then kept in a safe place and is regularly used to check the meter.

The best and most recognized method is to measure calibration shims using a written procedure. Calibration shims are available either as precision coated metal certified shims or plastic shims. Precision metal shims are naturally more precise. The steps for measuring them are described in a document called the calibration procedure, which is given by some manufacturers on request. The alternative is to return the instrument either to the manufacturer or its representative or to send it to a recognized laboratory to be calibrated there at a reasonable price.

Use it but don't overdo it

Now that you have finished the writing work, take measurements on the test panels or shims that came with your measurer. You can also use parts of your office furniture or other metallic painted object to make sure the measurer is working properly and that you are using it properly. Measurers come in different shapes and sizes. Make sure you know the correct way to hold and use your model. Most handheld scanners take one measurement at a time. Lift the probe from the surface at least 5 cm between measurements. Moving the probe across the surface shortens its life.

For best results and the longest possible life, position your fingers at the sliding ring around the probe.

Once the meter is in service, it should always be checked before use. Inspect your meter regularly and especially at the level of the probe and the probe cable. Constant pressure probes must be handled from top to bottom freely. The meter housing may work even if it is scratched, nicked or covered in paint, the probe not. Therefore, examine the probe carefully. So pay attention to the surface of the probe that comes in contact with the coating. Damaged, scratched or worn, the probes must be checked and if necessary replaced. Metal filings, dust and paint should be removed cleanly with a cloth.

Hot or rough surfaces are the most harmful to the probes of our thickness gauges. For the longest possible life, avoid prolonged exposure to hot surfaces and allow the probe to cool between each measurement. For rough surfaces, always lower the probe gently and never move it sideways on the surface. Plastic shims of known thicknesses can be placed on the surface to be measured to give protection to the probe. The measurement will be the thickness of the shim plus the paint thickness, but since the thickness of the shim is known, it will be easily inferred. Keep in mind that using extra thickness will increase the paint thickness error.

A meter calls for repair or service when the readings are lower than expected (often a sign of wear to the probe), when the readings are higher than expected (foreign material that can stick to the probe) or when the readings are erratic (a possible sign of a component failure).

Before putting it away

It is a good idea to check the probe head before putting it away. Fresh paint or other material can be removed and the problem can be directly solved, avoiding an unpleasant surprise the next time you use it. It is usually no problem for the user to leave the batteries and the probe attached for a short period of non-use. Put the meter back in its original bag or packaging. Cover the probe. Store the meter in a dry place, away from magnetic fluxes and extreme temperatures. When you go to find it for a new use, a quick check on a known thickness is. This excludes the need for scheduled and periodic maintenance. Do not forget to place the user manual and spare batteries next to the meter. Whether it is the magnetism or eddy current method of measurement, a coating thickness gage requires only a little regular attention to ensure years of accurate and reliable service.