K.C. Body Shop Supply

Call Us (773) 306-2805

How to: Prevent and Fix Loss
of Gloss on a Vehicle Paint Surface

My car paint finish isn’t as shiny as I expected it to be or used to be.
How can I restore the gloss?

Loss of gloss is a common issue. As the topcoat dries or ages, sometimes it dulls. Gloss can be restored by applying a compound or polishing the vehicle or, in severe cases, sanding and refinishing the impacted area of your car.

In this article, I’ll answer common questions about how to prevent loss of gloss and fix it when it happens.

  • What is loss of gloss?
  • What causes loss of gloss?
  • How can I repair a surface that has a loss of gloss?
  • How do I prevent loss of gloss?

What is loss of gloss?

Loss of gloss (also called hazing, dulling dieback, matting, or weathering) happens when the car’s topcoat surface dries with a dull or low sheen finish, or it ages and becomes dull over time.

What causes loss of gloss?

A loss of gloss in your car’s paint can be caused by one or more of the following:

  • The topcoat was applied in heavy, wet coats.
  • Inadequate flash time was allowed between coats
  • The topcoat or clear coat isn’t thick enough
  • Insufficient drying or curing time was allowed for the undercoats before the topcoats were applied.
  • A poor grade or too-fast evaporating thinner or reducer was used.
  • The substrate was improperly cleaned.
  • There was insufficient air movement during and after the paint application.
  • Spraying was done over a deteriorated or solvent-sensitive substrate finish without following proper priming or sealing procedures.
  • The loss of gloss may result from a natural weathering of the finish.

How can I repair a surface that has loss of gloss?

A surface showing signs of loss of gloss can be fixed in one of two ways, depending on the severity of the problem.

  1. For mild loss of gloss situations, allow the finish to cure thoroughly, then compound or polish to restore the gloss.
  2. For severe loss of gloss sand and refinish the affected surface.

How do I prevent loss of gloss?

There are several ways to prevent loss of gloss. These include:

  • Always apply the topcoat according to the product label directions using the recommended gun set-up and air pressure.
  • Allow a sufficient amount of flash time between coats.
  • Apply a sufficient number of coats to achieve the recommended film thickness. Check the thickness by using a film thickness gauge, if possible.
  • Allow all undercoats to thoroughly dry or cure before applying the topcoat.
  • Select the recommended thinner or reducer based on the temperature, humidity, air movement, and size of the repair.
  • Clean the substrate thoroughly before and after sanding.
  • For air-dry situations:
    • Allow the exhaust fan to run 40 minutes or longer after spraying.
    • Open the booth door after the finish is dust-free
    • Maintain a shop temperature of 60 degrees Fahrenheit or above, especially when drying overnight.
  • For a maximum holdout, use a premium two-component undercoat system.
  • Properly wash and care for the finish on a regular basis.
  • Use a premium topcoat color or clear coat system to provide maximum gloss and durability.

Doing these things will help create, restore, and preserve that wonderful gloss on your car paint surface.