Paint Problems
1. Loss of Gloss- aka Die Back or Sinking.
Causes- Primer coat was not cured or top coat was applied too heavy.
Prevention- Apply primer and or top coat to recommended manufacturer mil thickness. Pay close attention to flash off and dry time between coats.
Repair- A light buff may bring back gloss. In extreme cases cure, sand and refinish.
2. Dust Contamination- Dust particles embedded in the paint.
Causes- Improper cleaning of the vehicle, not cleaning the spray booth or not blowing off yourself or the vehicle.
Prevention- Vehicle being painted must be properly cleaned, booth must be kept clean and wear a clean paint suit.
Repair- Slight dust contamination can be sanded with 1200 grit sandpaper then buff and polish. Larger marks must be sanded and repainted.
3. Fish Eyes- aka Cratering. A small crater in the paint or clear.
Causes- contamination from the air, airlines, or panel.
Prevention- Very thorough cleaning of area being painted and check airlines for contamination.
Repair- Sand away paint layer, clean thoroughly and repaint.
4. Orange Peel- Paint has uneven texture similar to the skin of an orange.
Causes- Spray gun held too far away from surface being sprayed, spray pressure is too low, clear applied to lightly or reducer used is too fast.
Prevention- Use more air pressure, hold spray gun closer to the panel, use a slower reducer and slow down with spray gun.
Repair- If only minor, sand with 1200 grit sandpaper then buff and polish. If severe case of orange peel occurs, panel must be sanded with 800 grit sandpaper then refinished.
5. Runs- Excess paint or clear in one area causing beads or droplets.
Causes- Flash time between coats was not long enough, nozzle on gun was too large, coats of paint applied too thick or reducer was too slow.
Prevention- Where necessary use a smaller nozzle with better atomization, a faster reducer and long time in between coats.
Repair- Small runs can be sanded with 1000-1200 grit sandpaper then buff and polish. Larger runs must be completely sanded down and refinished.
6. Sanding Scratches- Sanding marks that are visible in the paint.
Causes- Primer or filler was sanded with paper too coarse, recommended dry time of primer was not adhered to, or using too fast a reducer in primer causing surface to bridge over.
Prevention- Use recommended grit sandpaper for the paint and apply black guide coat before the fine sanding of filler and primer.
Repair-Must be sanded and refinished.
7. Wrinkling- Irregular grooves/ridges that form on the surface. Mainly occurs on enamel finishes.
Causes- Topcoat applied too thick causing coats underneath to not properly dry or improper cleaning.
Prevention- Ensure the temperature and drying conditions are suitable.
Repair- In minor cases, allow surface to dry completely then sand down to the cured layer and refinish. In severe cases, entire paint system must be stripped and completely refinished.
Spray Guns
Devilbiss Spray Gun Service Center
Sata Spray Gun Trouble-Shooting Pages
Iwata Spray Gun Resource Center
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