How to Paint 3D Prints: Beginner's Guide to Finishing & Painting (2026)

Why Bother Painting 3D Prints?

A raw 3D print looks like a raw 3D print. Layer lines, shiny plastic, single colour — functional, maybe, but not exactly something you’d put on display. Proper finishing and painting transforms a £2 lump of PLA into something that genuinely looks manufactured.

I painted my first 3D print (a Mandalorian helmet) back in 2022. Terrible job. Didn’t sand, didn’t prime, just went straight in with a rattle can. The paint pooled in the layer lines, cracked within a week, and looked worse than the raw print. Lesson learned.

Since then, I’ve painted hundreds of prints — miniatures, cosplay armour, decorative pieces, functional parts. The process isn’t difficult once you know the steps, but skipping any of them shows.

Step 1: Sanding

Sanding is the least exciting part and the most important. Every layer line you don’t sand will show through your paint. No amount of primer covers deep layer lines.

What you need:

• Sandpaper: 120 grit, 220 grit, 400 grit (minimum)
• A bowl of water (for wet sanding)
• Patience

Process:

1. Start with 120 grit to knock down obvious layer lines and support scars
2. Move to 220 grit to smooth the surface
3. Finish with 400 grit wet sanding for a properly smooth finish
4. Rinse and dry the part completely

For flat surfaces, wrap your sandpaper around a sanding block — fingers alone create uneven pressure and dips. For curved surfaces, the foam-backed sanding pads from Screwfix (about £4 for a pack) work brilliantly.

I printed a Stormtrooper helmet last year and spent about 3 hours sanding it. Tedious? Absolutely. But the final painted result looked injection-moulded. The sanding did 70% of the work.

PLA vs ABS sanding: Both sand easily. ABS creates finer dust, so wear a mask. PETG is slightly gummier and can clog sandpaper faster — use wet sanding from the start with PETG.

The Acetone Shortcut (ABS Only)

If your print is ABS, you can skip much of the sanding with acetone vapour smoothing. Suspend the part over a small pool of acetone in a sealed container. The vapour melts the surface layer, smoothing out lines chemically. Takes 20-40 minutes depending on the part size.

Fair warning: it’s easy to overdo it. Leave a part too long and fine details dissolve into a blobby mess. Check every 10 minutes. And do this outdoors or in a well-ventilated space — acetone fumes are no joke.

This doesn’t work on PLA. PLA is not acetone-soluble. I’ve seen people try it online and wonder why nothing happened. Wrong plastic, that’s why.

Step 2: Priming

Primer does three things: fills micro-scratches, gives paint something to grip, and reveals imperfections you missed while sanding.

Best primers for 3D prints:

• Rust-Oleum Surface Primer (grey or white) — around £8 from Screwfix or Amazon UK. Excellent coverage, dries in 20 minutes
• Halfords plastic primer — good adhesion on PLA, about £9 a can
• Citadel Chaos Black / Grey Seer spray — expensive (about £14 from Hobbycraft or Games Workshop) but perfect for miniatures

Application tips:

• Shake the can for a full minute. Then another 30 seconds. Under-mixed primer spits and splatters
• Hold the can 20-25cm from the part
• Light, even passes. Multiple thin coats, not one thick coat
• Let each coat dry before adding the next (20-30 minutes between coats)

After the first coat of primer, check the surface under a bright light. You’ll probably spot scratches and dips you missed. Sand those with 400 grit, wipe clean, and apply another coat. Two to three coats total is normal.

Step 3: Painting

Here’s where it gets fun. You’ve got two main approaches: spray paint for speed and coverage, or brush painting for detail and control.

Spray Painting

Best for: helmets, armour, large decorative pieces, anything that’s mostly one colour.

Halfords spray paints (about £7-10 a can) are surprisingly good for 3D prints. Their matt black and metallic ranges are popular in the cosplay community for good reason. Montana Gold spray paints are a step up in quality but cost around £6-8 per can.

Same technique as priming — light passes, 20-25cm distance, multiple thin coats. Three coats gives solid coverage on most colours. Metallics often need four.

Brush Painting

Best for: miniatures, detailed models, multi-colour work.

Paint options:

• Citadel paints (Games Workshop) — the gold standard for miniatures. Available at Hobbycraft and GW stores. About £4-5 per pot. Proper job for tabletop minis
• Vallejo Model Colour — my personal favourite. Better dropper bottles, wider colour range, about £3 per bottle on Amazon UK
• Cheap craft acrylics — fine for large areas and base coats. The multi-packs from Hobbycraft (£10 for 12 colours) do the job

Brush painting tips:

• Thin your paints. Always. Two thin coats look infinitely better than one thick coat. Add a drop or two of water until the paint flows off the brush smoothly
• Use a wet palette — a piece of baking parchment over a damp sponge in a tupperware container. Keeps paint workable for hours
• Base coat first (darkest colour), then layer up to highlights
• For miniatures, washes are transformative. Citadel Nuln Oil or Agrax Earthshade settle into recesses and create instant depth. A £5 pot of wash makes a bigger difference than any other single technique

I painted a set of D&D miniatures for my brother’s birthday last year. Total material cost was about £18 — a pot of Nuln Oil, three Citadel base paints, and a cheap brush set. He thought I’d bought them pre-painted. That’s what proper technique does.

Step 4: Clear Coating

A clear coat protects your paint job from handling, UV exposure, and general wear. Skip this on display pieces if you want, but anything that gets touched needs sealing.

Options:

• Matte spray varnish — most popular for realistic, non-shiny finishes. Rust-Oleum or Plasti-kote, about £7-9
• Satin varnish — slight sheen, good middle ground
• Gloss varnish — for candy-coloured or metallic looks
• Brush-on varnish (Vallejo Matte Varnish) — better control for miniatures, about £4

Two thin coats. Let the first dry fully (at least an hour) before the second. Apply in a warm, dry space — cold or humid conditions cause clear coat to go cloudy (called “blushing”). I ruined a painted Boba Fett helmet by clear-coating it in my garage in November. Went milky white. Had to strip and repaint. Do it indoors.

Material-Specific Notes

PLA

The most common printing material and generally the easiest to paint. Sands well, takes primer beautifully, no solvent sensitivity with acrylics. The main risk is heat — PLA softens above 55-60°C, so don’t leave painted PLA parts on a sunny windowsill or in a hot car. The paint won’t save it from warping.

ABS

Tougher to print but arguably better for painting. More heat resistant, acetone-smoothable, takes spray paint without issues. ABS is the preferred material for cosplay armour for these reasons.

PETG

Sits between PLA and ABS. Harder to sand (gummier), but takes paint well once primed. Can’t be acetone smoothed. Not a bad choice for painted functional parts since it’s tougher than PLA.

Resin Prints

Resin prints have much finer detail and virtually no layer lines, making them ideal for painting. Wash and cure fully before painting, give them a light sand with 400 grit, prime, and paint. Resin miniatures look phenomenal with a proper paint job — they’re already halfway there off the print bed. See our best resin 3D printers if you’re considering the switch for miniature work.

Common Mistakes

Going too thick. This is the number one beginner error. Thick coats of primer, thick coats of paint, thick clear coat. Everything pools, drips, and obscures detail. Thin coats, always.

Skipping sanding. Yes, it’s boring. No, you can’t skip it. Layer lines through paint look terrible.

Painting in the cold. Spray paints behave differently below about 15°C. The paint dries slower, coverage is patchy, and clear coats go cloudy. Paint indoors or wait for a warm day.

Not waiting between coats. Each coat needs to dry before the next goes on. Rushing produces a tacky, soft finish that takes days to fully harden. Twenty minutes between primer coats, thirty between paint coats, an hour between clear coats.

What You’ll Spend

Full painting setup for a beginner:

Item	Cost	Where
Sandpaper multi-pack	£4-6	Screwfix, Amazon UK
Primer spray	£7-9	Screwfix, Halfords
Spray paint (2 cans)	£14-20	Halfords, Amazon UK
Clear coat spray	£7-9	Screwfix, Amazon UK
Brush + acrylic set	£10-15	Hobbycraft, Amazon UK
Total	£42-59

Not cheap, mind — but those supplies will last through dozens of projects. The sandpaper and primer get used fastest.

Related Guides

If you’re printing specifically for painting, choosing the right printer matters. Our guides to the best 3D printers for miniatures and best printers for cosplay cover which machines produce the best base for painting work.

Understanding filament types also helps you pick the right material for paintable parts — each plastic behaves differently under primer and paint.

Worth it? If you’ve ever looked at a grey PLA print and thought “that’d look incredible in copper” — absolutely.