Answer
For polishing prep, use the fine wet sanding grits in order. After the surface is level, move through 1000, 1200, 1500, 2000, and 3000 before polishing.
Why it happens
Polishing cannot hide deep sanding marks; the surface must first be refined with a steady fine-grit sequence.
Recommended grit
Use 1000 to start fine leveling, then refine with 1200, 1500, 2000, and 3000 before polishing.
Wet or dry
Use wet sanding for polishing prep when the coating or surface can safely be rinsed. Keep the surface and sheet clean.
Success check
The surface has an even fine haze from 3000 grit and no isolated coarse scratches before polishing.
What to do
- Confirm the surface is already level before starting polishing prep.
- Start with 1000 grit for normal fine sanding marks.
- Use 800 only when 1000 does not level the marks.
- Move through 1200, 1500, 2000, and 3000 grit in order.
- Rinse the surface and sheet before each finer grit.
- Sand with light pressure and a consistent pattern.
- Polish only after the 3000 grit pattern looks even.
Avoid: Do not polish over 800 or 1000 grit scratches that are still visible. They can show as haze or dull marks.