Foaming or cratering is the formation of bubbles and resulting small, round concave depressions in a paint film, during paint application and drying.

foaming and cratering

Possible Cause

Several things can cause foaming or cratering:

  • Shaking a partially filled can of paint.
  • Use of low quality paint or very old latex paint.
  • Use of a roller cover with wrong nap length.
  • Excessive rolling or brushing of the paint.
  • Applying a gloss or semi-gloss paint with a long nap roller.

 

Solution

All paints will foam to some degree during application; however, quality paints are formulated so the bubbles break while the paint is still wet, resulting in good flow and appearance. Use a quality synthetic roller sleeve (5mm nap for gloss & semi gloss and 12mm nap for low sheen and flat finish).


More problem solving advice

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