Sanding 3D prints means working through sandpaper grits, roughly 100 to 220 first and 600 to 1000 last, with light pressure and water, until layer lines fade. Wet sanding by hand keeps friction heat low, which matters most for PLA. Primer then shows what is left.
Research-based guide. This article is compiled from maker and service-bureau documentation and has not been checked on a test printer. Treat grit numbers as starting points and adjust to your part.
What grit sandpaper should you use on 3D prints?
Start at 100 to 150 grit to knock down the main layer ridges, then step through 220, 400, 600 and 1000 grit or finer. Hubs groups the stages as 100 to 220 for the initial pass, 320 to 400 for refining, 600 to 1000 for polishing and 1500 to 2000 and up for a near-mirror finish.
| Stage | Grit | Purpose |
|---|---|---|
| Initial | 100 to 220 | Flatten layer ridges and support scars |
| Refining | 320 to 400 | Remove the deep scratches from the first stage |
| Polishing | 600 to 1000 | Smooth surface, ready for primer or paint |
| Mirror finish | 1500 to 2000+ | Optional, mainly for resin or glossy parts |
Do not skip grits. Hubs warns that jumping from 150 straight to 600 leaves deep scratches that fine paper cannot remove, so you spend far longer on the later steps. Wipe the part with a tack cloth or rinse it between stages, because loose grit left behind can cut stray scratches.
Should you wet sand or dry sand a 3D print?
Wet sand, at least from about 400 grit upward. Hubs says water cools the surface, keeps debris from clogging the paper and gives a finer finish, and that dry sanding can soften PLA and make it gum up because friction generates heat. The first coarse passes can be dry if you keep the pressure light and stop when the plastic feels warm.
Light pressure matters as much as water. Hubs notes that pressing hard creates localized heat that leaves uneven flat spots on curves. Sand in circular or crossing strokes rather than straight along the layer lines, since sanding parallel to them can deepen the valleys between layers.
Can you sand PLA, PETG, ABS and resin the same way?
No. The technique is the same, but heat sensitivity differs by material. Hubs rates PLA as very sensitive to heat and advises hand sanding wet without power tools, because they melt the plastic quickly. BCN3D likewise warns that sanding PLA with an electric tool can deform the model, and recommends power tools only for high-heat-resistance materials.
- PLA: hand sand, wet, light pressure. See PETG vs PLA for how the two differ.
- PETG: moderate heat sensitivity. Hubs prefers wet sanding because high friction makes it gum up.
- ABS and ASA: sand dry or wet. Hubs says acetone vapor can give a glass-like finish on these two only. Our ASA vs ABS comparison covers the materials.
- Resin: low heat sensitivity but brittle. Hubs suggests starting near 400 grit to avoid deep scratches, and wearing a mask because the fine dust should not be inhaled. Follow the resin safety guide and your resin maker's advice.
How do you sand a 3D print step by step?
- Remove supports and blobs first. Clean up support scars before sanding. If supports are fused, see how to fix supports stuck to a print.
- Pick a starting grit. Use 100 to 150 grit for pronounced layer lines, or a finer grit for resin or already smooth prints.
- Sand lightly with water. Use circular strokes and rinse the paper often so it does not load with plastic.
- Move up one grit at a time. Go to 220, 400, 600 and 1000, sanding until the scratches from the last grit are gone.
- Clean the part. Rinse or use a tack cloth between stages.
- Use sponges or files for detail. BCN3D says abrasive files suit fine or narrow details better than paper.
Print settings decide how much work this takes. Thinner layers leave shallower ridges, as the layer height guide explains, and Hubs notes that good post-processing cannot fully fix a poor print.
How do you fill, prime and finish a sanded print?
Fill what sandpaper cannot reach, then prime. Hubs recommends filler for deep gaps and internal voids, sanded flush once dry, with polyester-based filler or glazing putty for deep gaps. Several coats of high-build primer then fill micro-scratches and make any remaining ghost layer lines easier to spot, so you can sand those spots again.
BCN3D adds that primer removes porosity left by sanding and improves paint adhesion. Apply it in several coats, letting each dry, and paint in layers. Check that paints and coatings contain no solvents that react with the model, because ABS and PLA have low chemical resistance.
What are the alternatives to sanding 3D prints?
Epoxy coating, gap-filling primer and acetone vapor all smooth a print with less sanding or none. Hubs describes an epoxy coating such as XTC-3D as self-leveling into the layer lines without removing material, and gap-filling primers as masking texture when built up in coats. Acetone vapor works only on ABS and ASA, and over-exposure melts fine detail and rounds sharp edges.
Smooth-On says XTC-3D mixes 2 parts A to 1 part B by volume, has a 10 minute pot life and is tack-free in about 2 hours. It is brushed on in one thin layer, under 1/64 inch, and can be sanded, primed and painted once cured. Its page recommends ventilation, gloves, glasses and a NIOSH-approved respirator, and warns that large mixed batches heat up. Ironing is a slicer-side option for flat tops, covered in ironing explained.
What safety steps matter when sanding 3D prints?
Control dust and heat. Wear a mask when sanding resin, per Hubs, and a mask and goggles with fiber-filled filaments, per BCN3D. Wet sanding also keeps dust down. Keep pressure light to avoid heat damage, and read the safety data for any filler, primer or coating you use. For printer and fume guidance see 3D printer safety basics.
