Occurrence
Scratches visible singly or in large numbers on the paint surface which look like sanding lines.
Causes
- Sanding with too coarse abrasives
- Insufficient curing of the filler
- Insufficiently sanded polyester putty
- Insufficient insulation of the putty prior to topcoat application
Prevention
- Use paper of the recommended gradation
- Isolate the filled areas with filler primer
- Cure the primer well
- Use drying times recommended by the manufacturer
Removal
Sand down and reapply both primer and topcoat.