The Complete Post-Processing Guide: Sanding, Painting, and Finishing 3D Printed Parts
· general
A freshly printed 3D part rarely looks like the final product. Layer lines, support scars, powdery SLS surfaces — all need work before a part is ready for presentation.
Why Post-Processing Matters
FDM: Visible layer lines, rough surface near supports
SLA: Smooth but support scars remain at contact points
SLS: Chalky, powdery surface — needs preparation before painting
Step 1: Cleaning and Support Removal
FDM: Snap/peel breakaway supports. Water-soluble PVA supports dissolve in warm water.
SLA: Wash in IPA for 10–15 min → air dry → UV cure 5–15 min → remove supports after curing.
SLS: Brush and compressed air to remove unsintered powder.
Step 2: Sanding
Always wet-sand above 400 grit. ABS only: Acetone vapor smoothing greatly reduces layer lines.
Step 3: Priming
Spot putty: Fill small holes, dry, sand flush
XTC-3D epoxy: 2-part epoxy on FDM parts, self-levels, covers layer lines
Filler primer: 2–3 thin coats, cure 1–24 hours, sand at 400–600 grit
Step 4: Painting
Spray: Distance 20–30cm, multiple light passes, 3–4 coats.
Step 5: Clear Coating
Typical Timeline for Presentation-Ready Part
Sanding (1–3 hrs) Priming cure (24 hrs) Painting cure (24 hrs) Clearcoat cure (24 hrs) = 3–5 days total
Frequently Asked Questions
Does sanding affect dimensional accuracy?
Yes — aggressive sanding removes material. Design with 0.1–0.2mm extra allowance for parts with tight-fitting features.
Which parts can't be finished to look injection-molded?
Very thin walls and small fine features highlight layer artifacts even after finishing. SLA is the better starting point for fine-detail parts.
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Need your parts finished professionally? Upload your file and mention your finishing requirements — we handle printing through final clear coat.
Does sanding affect dimensional accuracy?
Yes — aggressive sanding removes material. Design with 0.1–0.2mm extra allowance for parts with tight-fitting features.
Which parts can't be finished to look injection-molded?
Very thin walls and small fine features highlight layer artifacts even after finishing. SLA is the better starting point for fine-detail parts.
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*Need your parts finished professionally? [Upload your file](https://3dforger.online?utm_source=blog&utm_medium=cta&utm_campaign=post_processing) and mention your finishing requirements — we handle printing through final clear coat.*