Sanding 3D prints
Sanding 3D prints is one of the most accessible and effective post-processing techniques for improving surface finish, especially for FDM-printed parts. While 3D printing allows you to create complex shapes, the layer lines left by the additive process often require manual refinement — especially for parts that will be painted, assembled, or displayed. Whether you’re going for a smooth matte look or prepping a surface for a high-gloss finish, sanding helps eliminate visible stepping, support marks, and minor imperfections.
Let’s take a look at how to do it properly — and efficiently.
When and why to sand
Sanding is typically used on parts made from PLA, PETG, ABS, or resin prints with thicker support points. It’s essential when:
- layer lines are too visible and need to be removed,
- you plan to paint or coat the part,
- support contact points leave minor surface damage,
- you want a smooth, tactile feel in functional components.
Not all prints need sanding, but if the final aesthetic or fit matters, it’s often worth the extra effort.
How to sand 3D prints smooth?
Start with coarse sandpaper — around 100–150 grit — to remove layer lines and support scars. Work gradually through finer grits (220, 400, 600, even up to 1000+) to build a smooth finish. Keep sanding in the same direction and avoid pressing too hard; let the grit do the work.
For best results:
- Use a sanding block or foam pad for flat surfaces.
- For curved or detailed parts, use flexible sandpaper or sanding sponges.
- Rinse between grits to remove plastic dust.
- Finish with very fine grit if painting or polishing is planned.
This progressive technique is key to sanding 3D prints smoothly, especially on PLA, which tends to scratch easily.
| Material | Initial grit (rough shaping) | Medium grit (layer removal) | Fine grit (smoothing / pre-paint) | Ultra-fine grit (polishing) |
|---|---|---|---|---|
| PLA | 120–150 | 220–320 | 400–600 | 800–1000+ |
| PETG | 100–150 | 220–320 | 400–600 | 800–1000 |
| ABS | 100–150 | 220–400 | 600–800 | 1000+ |
| Resin (SLA) | 220 | 320–400 | 600–800 | 1000–2000 |
| Nylon / PA | 120 | 220–320 | 400–600 | Optional (material stays matte) |
Wet sanding 3D prints
Wet sanding 3D prints involves dipping the sandpaper in water to reduce friction, minimize heat, and trap dust. It’s especially useful with fine grits (400 and above) when you want a polished finish. Water acts as a lubricant, helping the paper glide and reducing the risk of melting the plastic from heat buildup — particularly important when working with ABS or PETG.
Just make sure your part is waterproof or already sealed, and always dry it thoroughly between grit changes.
Using a Dremel for sanding 3D prints
For speed or detailed areas, sanding 3D prints with a Dremel can save time — but it requires precision. Use low speeds and soft attachments like sanding drums or polishing wheels. A Dremel for sanding 3D prints is best suited for rough trimming, inner corners, or quick surface prep on durable materials like ABS or PETG.
Avoid using high speed or too much pressure — it can gouge the part or even melt the surface.
Final notes on technique
Sanding is an art of patience and control. Always test your approach on a non-critical surface before finishing a visible area. Use good lighting, ventilated space, and (especially for resin or ABS) wear a dust mask — plastic particles can be fine and irritating.
Done well, sanding transforms a rough prototype into a display-worthy part, ready for priming, painting, or use.
Explore also
Related categories
