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How to: Prevent and Fix Solvent Popping in a Car Paint Finish

How can I fix the small crater-like openings in my car paint?

After painting your car, you notice tiny bubbles, pinholes, or crater-like openings in the paint finish. This is known as solvent popping. It can be repaired by sanding and refinishing or, in severe cases, by removing the affected film, applying new primer, sealing, and recoating the surface.

In this article, I’ll answer common questions about how to prevent solvent popping and eliminate it when it happens.

  • What is solvent popping?
  • What causes solvent popping?
  • How can I repair a surface showing signs of solvent popping?
  • How do I prevent solvent popping?

What is solvent popping?

Solvent popping (also called boiling or blowing) describes blister-like bubbles   on a paint finish when it starts to dry and cure.

What causes solvent popping?

The solvent popping pinhole craters are caused by liquid solvents (thinners or reducers) trapped below the finish and pushing through and “popping” to the paint’s surface as it dries. Possible causes of solvent popping are:

  • You used a thinner or reducer that evaporated too quickly for the spraying conditions.
  • You allowed inadequate flash time between coats.
  • You applied coats that were too heavy or wet, causing excessive film thickness or piling on.
  • There was too much air movement during application, causing the surface to skin over before the solvents evaporated.
  • You allowed too much purge or flash time before force drying.

How can I repair a surface with solvent popping?

A paint surface with solvent popping can be fixed in one of two ways, depending on the severity of the problem:

  • For mild solvent popping, allow the finish to cure thoroughly, then sand smooth and refinish.
  • For severe solvent popping, remove the affected surface, then prime, seal and recoat.

How do I prevent solvent popping?

There are several ways to prevent solvent popping, including:

  • Always select the recommended thinner or reducer based on the temperature, humidity, air movement, and the size of the repair. Learn how to choose the right reducer for different weather conditions.
  • Allow for adequate flash time between coats.
  • Avoid doubling wet coats of paint.
  • Restrict the air movement over the surface being painted.
  • Avoid a long purge or flash time before force drying.

Doing these things will keep solvent popping from happening on your paint surface.