What is pinholing?

Pinhole (Pinhole) is a small hole or hole on the surface of a coating, paint, coating film, etc., usually refers to a hole with a diameter of less than 0.5 mm. They may be caused by defects, particles, bubbles or contaminants on the surface of the coating or substrate. The presence of pinholes may cause the failure of the coating or coating film, as they may allow liquids, gases or other substances to pass through the thickness of the coating or coating film and enter the bottom layer or substrate, causing corrosion, deformation or other damage.

The appearance of pinholes is usually related to factors such as the quality of the paint or substrate, construction conditions, surface treatment, etc. For example, if the surface treatment is not thorough or the coating thickness is insufficient, it may make pinholes easier to form. In addition, conditions such as high temperature, high humidity, airflow, and static electricity may also increase the formation of pinholes.

In order to avoid the formation of pinholes, adequate surface treatment is required to ensure uniform thickness of the coating and to adhere to the coating manufacturer's construction guidelines. The detection of pinholes can be performed using microscopy or high-resolution image technology. If pinholes are found in the coating, a filler or pinhole repair agent can be used to fill the holes and recoat the surface to prevent continued damage.