7. Coating Failures

7.4 Types of Failures

5. Application Related Failures

  1. Holidays or Misses

  2. Pinholes

  3. Cratering

  4. Dry spray

  5. Runs or Sags

  6. Orange Peel

 

(A) Holidays or Misses

Identification:

These are bare areas on the surface which have not been painted. This defect is caused by the painters applying the paints in bad lighting conditions or by a poor application technique.

 

Description:

Adjacent figures demonstrate this type of failure.

 

Remedy:

  • Apply the coat without leaving any area.

  • Overlap each pass by at least 50%.

 

 

 

 

 
Detection Tools:

 

Holiday detection tool

Holiday detector with coil spring electrode

(B) Pinholes

Identification:

These are tiny deep holes on a coated surface extending to the substrate. They may appear as bubbles up to 1 mm in diameter pierced at the top.

 

 

Description:

Tiny holes are developed by insufficient paint spray or by improper spraying technique. The diameter of the pinhole increases with thickness of paint film.

 

Remedy:

  • If uncured, brush out and apply additional coat. If cured, apply additional coat.