Bottom line: sanding and polishing succeed with progressive grits, a flat base surface and control of friction heat. Start coarse only if defects require it, then step through finer grits. Wet sanding reduces heat and clogging, especially on PLA and PETG.
Sequence
| Stage | Grit | Note |
|---|---|---|
| Defect removal | 400–600 | Light pressure |
| Levelling | 800–1200 | Follow layer direction |
| Finishing | 1500–3000 | Wet sand to limit heat |
| Polishing | Compound | Match the material |
Material notes
- PLA: heat-sensitive, use wet sanding.
- PETG: can whiten if over-sanded.
- ABS/ASA: can be smoothed with solvents.
- TPU: shaping and coating work better than sanding.
- Filled materials: use dust protection.
Costly mistakes
- Skipping grits.
- Leaving layer ridges behind.
- Melting the surface with friction.
- No dust protection.
- Using incompatible polishing compounds.
Buyer / engineer checklist
- Are defects filled first?
- Are grits progressive?
- Is heat controlled?
- Is the compound compatible?
- Is dust protection in place?
Tell us the material and target finish and we can outline the process.Finishing advice