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How to Fix Bubbling, Pinholes & Cratering

Paint Blistering.
Description

What is Bubbling, Pinholes & Cratering in Paint?

Formation of air bubbles (foaming) and resulting small, round concave depressions (cratering) when bubbles break in a paint film during drying.

What Causes It?

  • Shaking a partially filled can of paint or using too high of a speed when using a drill mixer.
  • Excessive brushing or rolling – applying a paint too rapidly – will drive excess air into the film.
  • Use of a roller cover with wrong nap length.
  • Applying a gloss or semi-gloss paint over a porous or unsealed surface.
  • High heat during application speeds up drying; any bubbles or craters that form dry before they can break and level out.
  • Using a reducer that is inappropriate for the coating.
Solution

How to Fix Bubbling, Pinholes & Cratering

  • All paints will foam to some degree during mixing and application; most paints are designed to allow these bubbles to break and flow smooth during drying.
  • Allow the coating to dry thoroughly, sand the coating smooth, and repaint.
  • Slowly stir partially filled containers to prevent entrapping excess air in the coating.
  • If there is a very noticeable amount of air bubbles during application, try slowing down.
  • Follow label and data page directions for the appropriate applicator. Determine the correct roller cover based on the coating being applied and the surface.
  • On smooth surfaces, 1/4", or 3/8" roller nap is usually sufficient. On textured surfaces, a 3/4" nap or greater is needed.
  • Prime porous surfaces before topcoating.
  • Allow each coating to dry properly before topcoating.
  • Follow label and data page directions for the appropriate thinner/reducer and amount to use.
Recommendations

Suggested Finishes

Reapply the same or an upgrade coating.