Solvent Pop_Blog

Troubleshooting: Solvent Trap (Pop) in Automotive Paint

Description: A “goose pimple” or volcano-like appearance in paint film which, on close examination, frequently contains small holes at the center of the bumps.


  • Improper evaporation of solvent from wet paint film during initial cure or force dry
  • Improper application of product: product applied to heavily; inadequate flash time between coats
  • Incorrect mix ratio/viscosity
  • Incorrect hardener/reducer for shop temperature

Corrective Action Checklist:

  • Check to determine if defect is on entire unit or in just a specific area
  • Check for high temperature in first part of force dry
  • Check other units on line to determine if a pattern exists
  • Check for correct reducing solvent
  • Check whether defect is specific to one or many colors
  • Check whether defect is most prevalent on horizontal surfaces
  • Check for excessive film builds
  • Check for high fluid delivery
  • Check for low air pressure
  • Check for high viscosity
  • Check for too much overlap in film build
  • Check for proper flash and purge times


  • Allow adequate flash times
  • Choose a suitable hardener/reducer for size of repair and booth temperature
  • Check viscosity using a #2 Zahn Viscosity Cup


  • Minor pop can be sanded and buffed
  • Severe pop must be thoroughly sanded and repainted


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