What Does Bridging Mean?
Bridging is a visible coating defect that occurs due to insufficient surface preparation or an improper coating application on a metal surface with the intention of preventing corrosion. It is characterized by gaps on the metal substrate's surface that have been filled with a coating or other fluid.
Corrosionpedia Explains Bridging
Bridging is the covering of unfilled gaps, cracks or corner joints with a coating, which introduces a weakness in the paint film due to intermolecular and structural discontinuity.
Bridging may be prevented by carefully evaluating the chemical composition of all paint components and understanding how they react to a given curing temperature. Highly viscous paint systems tend to increase the likelihood of bridging.
In the event of bridging, the applied coating should be removed, the gap filled and then the coating reapplied on a more uniform surface.