K.C. Body Shop Supply

Call Us (773) 306-2805

How to: Prevent and Eliminate Cracking on a Vehicle Paint Surface


How can I prevent cracking on a car paint surface?

Cracking appears in the form of lines in the topcoat finish resembling the cracking of dried mud. It can be eliminated by removing all cracked paint film and refinishing the impacted area.

In this article, I’ll answer common questions about preventing cracking and eliminating it when it happens.

  • What is cracking?
  • What causes cracking?
  • How can I repair a surface with cracking?
  • How do I prevent cracking?

What is cracking?

Cracking (also known as crowfeet, alligatoring, crazing, or
checking) shows up as distinctive lines or cracks appearing in the auto finish topcoat.

What causes cracking?

Cracking can be caused by several factors, including:

  1. The undercoat and/or topcoat were applied too thick
  2. Refinishing was done over a crazed or cracked surface.
  3. Not enough flash time was allowed between coats and/or undercoats, or they were force-dried using air from the spray gun.
  4. Paints or finishes were mixed incorrectly, or too much hardener was used.
  5. The paint ingredients have not been thoroughly stirred or agitated. Check out our tips for stirring and shaking auto paint and finishes.
  6. The finish has broken down due to prolonged exposure to sunlight, moisture, or extreme temperature changes.


How can I repair a surface with cracking?

Repairing cracked paint film is a two-step process:

  1. Remove all cracked paint film.
  2. Refinish the impacted area.

How do I prevent cracking?

Prevent cracking by following these seven steps:

  1. Apply all materials following the label directions.
  2. Completely remove all crazed and cracked finishes before refinishing.
  3. Do not force-dry undercoats!
  4. Mix all ingredients thoroughly, using the recommended additives. Add each component in the proper order following the recommended mixing ratio.
  5. Stir or agitate materials thoroughly before using them to ensure all ingredients are well-blended in the solution.
  6. Use a premium two-component undercoat and topcoat system to provide maximum gloss and durability.
  7. Use a good-quality thinner or reducer and hardener, measuring the amount of each accurately.

By carefully following this advice, you’ll be able to prevent cracking in your topcoat finish.