What is a common cause of blistering in coatings?

Blistering in coatings is often caused by surface contamination. When contaminants such as dust, oil, grease, or moisture are present on a substrate before the application of a coating, they can interfere with the adhesion between the coating and the surface. This poor adhesion allows moisture to become trapped beneath the coating layer, leading to the formation of blisters or bubbles.

The presence of contaminants prevents the coating from properly bonding with the substrate, which is crucial for the longevity and performance of the coating. For instance, if the surface is not clean and properly prepared, the coating may not adhere firmly, resulting in moisture accumulation and subsequent blistering.

While factors like poor weather conditions, using the wrong type of brush, or over-application of paint can contribute to other coating defects, the direct relationship between surface contamination and blistering makes it the most common cause in this scenario. Ensuring that surfaces are thoroughly cleaned and free from contaminants before coating application is a fundamental step in preventing blistering and achieving a durable finish.