How can I get rid of sand scratches on my paint surface?

Sand scratches are the streaks, lines, or marks that appear in your paint film because the substrate was not properly sanded. Restoring a smooth finish requires sanding and refinishing.

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

• What are sand scratches?
• What causes sand scratches?
• How can I repair a surface showing signs of sand scratches?
• How do I prevent sand scratches?
  
  

What are sand scratches?

Sand scratches are the streaks, lines, or marks appearing in your paint film because the body or primer was not sanded properly.

What causes sand scratches?

There are seven reasons why sand scratches appear in a finish.

1. You sanded the substrate using grit sandpaper that was too coarse.
2. You allowed insufficient dry or cure time for the undercoats before the sanding and application of the topcoat.
3. You refinished over soft, soluble substrates (e.g., lacquers, uncured OEM).
4. You used a poor-grade or too-rapid evaporating thinner or reducer for the spray conditions resulting in:
5. The sand scratches were “bridged” over to the primer surface.
6. The topcoat skinned over, trapping the solvent which swelled sensitive substrates.
7. You used a solvent cleaner that was too strong for the substrate, or a thinner or reducer as a surface cleaner after sanding.
   
   

How can I repair a surface showing signs of sand scratches?

To repair a surface showing signs of sand scratches, you can:

• Allow the finish to dry or cure, then sand smooth and apply compound or polish to restore the gloss.
• For severe cases, Sand and refinish.
  
  

How do I prevent sand scratches?

Here are things you can do to prevent sand scratches:

• When sanding, always use the recommended grit sandpaper.
• Allow undercoats to thoroughly dry or cure before sanding and top coating.
• Rub a small area of the old finish with a shop towel saturated with lacquer thinner. If the old finish is soluble or under cured, apply an appropriate sealer.
• Select the recommended thinner or reducer, based on the temperature, humidity, air movement, and size of the repair.
• Use a solvent cleaner designated for either lacquer (soluble) orcured enamel or urethane (insoluble) substrates.

Taking these steps will help prevent sand scratches from appearing in your paint film.