Surface Defects: Diagnosis and Cure

By Clifford K. Schoff

Surface defects are as old as paint itself and have plagued generations of paint technologists. Some people think that we should have cleaned up the defects and gotten rid of them years ago, yet they are more common than ever. Why do defects occur so often?

Why are coatings so different from the materials they coat? Why is it so difficult to solve defect problems? What can we do about them? This paper attempts to answer these and other questions.

It addresses a number of defects and their causes, including craters and other surface tension related defects, dirt (the most common defect of all), popping, and flow problems. It also reviews techniques for defect identification and root cause analysis and discusses countermeasures.

Examples and case histories are used to illustrate defects and methods of attack to characterize and cure them. The communication and organizational difficulties that often compound defect problems rather than help solve them also are considered.