Pop

The Pop defect is a blister-like surface defect caused by solvents trapped in the paint film. The defect often appears like boiling or bubbles in or on the paint film.  Defects are most often observed in the baked film which upon cross section reveal voids in the film.  The defect is formed when liquid solvent, or air, becomes trapped under the paint layer after the surface layer lightly cures or “skins-over”.  The solvent then vaporizes through or “pops” through the partially cured upper layer to leave the void defect.

Also known as:  Solvent pop, solvent trap, boiling, blowing, air entrainment

Pop is normally caused by high film build of the coating layers.  The condition can be made more severe when the flash time of the layers does not follow the process guideline.  Equally important is the bake ramp and conditions in the first portion of the oven.  Air entrainment can be caused by defective bell cup applicators or anomalies sin the paint delivery system.

1.  Excessive-high film build of paint -out of specifications

2.  Flash-off time between layers not to process

3.  Flash-off time before baking step not to process

4.  High temperature of the substrate prior to application

5.  Improper booth air flow -note recessed areas

6.  Severe IR heated flash of waterborne paint

7.  Booth Temperature and Humidity outside of design window

8.  Application viscosity of the paint is out of specification

9.  Solvent reducer is not as specified for the process

Consult your specific paint shop procedures.

• Finesse Deck:  Sand plus 2-step Polish
• Spot Repair:  Sand plus Repaint