What can cause "blistering" in a coating?

Blistering in a coating is primarily caused by trapped moisture or improper surface preparation. When surfaces are not adequately cleaned or dried before applying a coating, moisture can become trapped beneath the film. This moisture may vaporize during the curing or drying process, leading to the formation of blisters as it expands. Proper surface preparation is crucial to ensure that all contaminants, including oils, dust, and moisture, are removed, allowing for better adhesion and preventing issues like blistering.

While other factors such as unsuitable environmental conditions, poor adhesion, or over-application can influence coating performance, they do not directly relate to the specific mechanism of blistering. For instance, unsuitable conditions can lead to other types of application problems, and poor adhesion may result in peeling rather than blistering. Over-application of paint can lead to runs or sagging but not typically blistering from trapped moisture. Hence, the most direct cause of blistering remains linked to those struggles with moisture retention and inadequate surface preparation.