Answer
Use light pressure, clean the sheet, and move to finer grits. For plastic, 320 or 400, then 600+ works best.
Why it happens
Too much pressure, too much speed, or a clogged sheet can create heat and soften plastic.
Recommended grit
Use 320 or 400 for prep, then 600 and finer with light pressure.
Wet or dry
Wet for fine stages to control heat and residue.
Success check
The plastic cuts cleanly without smearing or softening.
What to do
- Stop sanding and let the plastic cool.
- Clean the paper and surface.
- Resume with lighter pressure.
- Use 600 or finer for final smoothing.
Avoid: Do not keep sanding hot or gummy plastic.