Painting Defects

Bronzing

This is a defect that was often observed on cars painted red or blue where after a period of time a characteristic red tone developed on the paint surface. The cause was older types of pigments like phthalocyanine or Prussian blues. The defect is not common with the pigments available today.

Chalking

Chalking is the powdery deposit on the surface of the paint which dulls the gloss and appears after exposure. This defect is usually associated with long exposures to sunlight and is a natural degradation of the paint film. Some combinations and types of pigments and resins show more pronounced chalking than others.

Checking

Checking is the appearance of wide splits with round edges that occur in the top coat. The cause is usually due to the surface not being clean (could be old paint) or too high a film build or the materials not being mixed properly. The remedy is to remove the old paint, cleaning the surface and mixing the paint ingredients properly.

Cracking or Crazing

This defect is a series of irregular cracks in the surface of the paint.

The cause of this defect can be:

• Application of the top coat before the previous coat is dried
• Too thick of a top coat
• Impurities on the surface or the effect of impurities on the applied coat.

The remedy is the let the intermediate coats dry before the top coat is applied, clean the surface well, remove the previous coat or ensure that the top coat is not applied too thickly.

Posted in: BGAS Grade 3/2,BGAS Study Material,Bronzing,Chalking,Checking,Cracking or Crazing,Painting Defect and Definition,Painting Defects