Automotive Coating Application Defects

By Clifford K. Schoff

Spraying is the worst possible way to apply automotive coatings if minimization of surface defects is desired, but it is the only way to obtain the gloss, color effects, and outstanding appearance that car buyers demand. This article surveys some of the defects that automotive coatings experience when they are applied.

Craters undoubtedly are the most infamous and cause the greatest panic in the auto plant, but a number of other defects can occur. All defects hurt appearance and some also can interfere with the corrosion or weathering protection aspects of the coatings. Repairing of defects can lead to more problems, so the best strategy is to prevent them from occurring. Many of the common day-to-day defects seen on car bodies are surface tension driven.

These include craters, dewetting, telegraphing, picture framing (fat edges), and poor edge coverage.