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How to: Prevent and Eliminate Transparency
When Painting Vehicle

I can see my old car paint color under my new one. How can I fix this?

After painting your car, you notice that the original finish or undercoat is visible through the topcoat. This is known as transparency. It can be repaired by applying additional coats of the finish color or sanding, applying more undercoat, and refinishing.

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

  • What is transparency?
  • What causes transparency?
  • How do I prevent transparency?
  • How can I repair a surface showing signs of transparency?
  • Is there else I should know to prevent transparency?

What is transparency?

Transparency (also called poor hiding, poor coverage, or translucence) is when the original car finish or undercoat is visible through the new finish.

What causes transparency?

Many of the causes of transparency result from mistakes made by the painter and can be easily corrected. Here are five reasons transparency may be happening:

  • You did not stir or agitate the paint thoroughly.
  • Your paint was over-thinned or reduced.
  • Your substrate was not uniform in color.
  • You used the wrong color of undercoat.
  • You applied an insufficient number of color coats.

How can I repair a surface showing signs of transparency?

There are two ways to fix transparency:

  1. Apply additional coats until you achieve a solid color surface.
  2. Sand the surface, then apply another undercoat of a similar color, then refinish.

How do I prevent transparency?

Take these steps to avoid transparency:

  1. Stir or shake your paint thoroughly, ensuring all pigment is well-mixed within the solution.
  2. Be sure to thin or reduce your paint according to the product label directions.
  3. Use a sealer or ground coat to provide a uniform color before applying the finish.
  4. Use an undercoat that’s similar in color to the finish.
  5. Keep spraying until you achieve a uniform color surface.

Is there anything else I should know to prevent transparency?

Spray monitors, such as a hiding sticker or opacity charts, show the hiding power or transparency of paint when it’s being applied. When you can no longer see black and white through the color, you’ve achieved complete coverage.

Following these tips will prevent your old paint color from showing through your new one.