How to deal with grinding marks on car paint surface？
1. Definition:
Swirl-like sanding marks in the substrate appearing on topcoats or on refinish surfaces.
2. Reason:
(1) The substrate was sanded with too rough sandpaper. Due to the thicker film formation, the paint shrinks more at the sanding marks.
(2) The drying time of the base coat was not followed correctly: Due to the expansion of the base coat material when painting and the shrinkage after drying, the sanding marks are very clearly visible.
(3) The applied filler and topcoat are too thin to cover the sanding marks of the lower coating.
(4) Wrong grinding method and/or improper sander used.
3. How to avoid:
(1) Use the specified grade of sandpaper. Use a secondary grout when sanding.
(2) Follow the recommended drying time.
(3) Follow the recommended film thickness.
(4) Before starting the machine, place the sander on the paint surface. When painting in dry grinding, the eccentric stroke should not be greater than 5 mm.
4. Maintenance:
Refinish with suggested primer and/or topcoat after sanding.
