Thickness Measurement of Gel Coating on Glass Fiber Hull

Gelcoat is a hard polyester resin coating. Polyester resin has the characteristics of wear resistance, impact resistance, and low friction coefficient. One of its widespread uses is marine products, such as the hulls of yachts and motorboats. It is most commonly used on fiberglass boat hulls, where it is coated on fiberglass to form a smooth and shiny protective surface that is both beautiful and prevents damage to the coated surface from some harmful environmental and chemical substances.

We received a sample from a shipping company of our customer - a fiberglass hull with gel coat. They needs to measure the thickness of the gelcoat to ensure that it is within the specified range. Usually the thickness range is about 0.25 mm to 1 mm, in most cases the thickness is about 0.5 mm.

We Use YUSHI PM-5 series ultrasonic thickness gauge for testing, use a high-frequency single crystal delay line probe to measure the thickness of gel paint layers of different thicknesses. The echoes are clear, convenient and fast, and the measurement values are correct.

The A-scan waveform display of PM-5 series ultrasonic thickness gauges is useful for determining the effectiveness of echoes and verifying correct readings. The inner surface of a gelcoat is typically rough and irregular, and due to this uneven geometry, the echoes from the gelcoat-fiberglass boundary vary greatly. Because manufacturers are usually most concerned with ensuring that the gelcoat meets the minimum thickness, keeping the probe perpendicular to the surface of the material being measured during measurement can be used to verify the minimum gelcoat thickness through the A-scan waveform.

If you would like to know more about using ultrasonic technology to measure material thickness, or if you have a problem in the measurement application, welcome to contact us to send sample testing and provide you with a best solution.