Answer
For acrylic tubs, use fine wet sanding only: 1000, 1500, 2000, and 3000 before polishing.
Why it happens
Acrylic surfaces need very fine wet sanding and polishing for small surface marks.
Recommended grit
Use 1000, 1500, 2000, and 3000 only for light scratches before polishing.
Wet or dry
Wet.
Success check
The scratch is reduced and the surface is ready to polish.
What to do
- Clean the acrylic tub first.
- Test a hidden spot before visible repair.
- Wet sand light scratches with 1000 through 3000.
- Polish after sanding.
Avoid: Do not use coarse grit on acrylic tub surfaces.