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

Why Bother Painting 3D Prints?

A raw 3D print has visible layer lines, shiny plastic, and a single colour. It may be functional, but it rarely looks ready for display. Proper finishing and painting can transform a £2 lump of PLA into something that looks manufactured.

I painted my first 3D print, a Mandalorian helmet, in 2022. It was a terrible job. I didn’t sand or prime it and 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, including miniatures, cosplay armour, decorative pieces, and functional parts. The process isn’t difficult once you know the steps, but the results show when you skip one.

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 will cover 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 because fingers alone create uneven pressure and dips. For curved surfaces, the foam-backed sanding pads from Screwfix (about £4 for a pack) work well.

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, so use wet sanding from the start.

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 and smooths out lines chemically. The process 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. Do this outdoors or in a well-ventilated space because acetone fumes are no joke.

This method doesn’t work on PLA because PLA is not acetone-soluble. I’ve seen people try it online and wonder why nothing happened. They were using the wrong plastic.

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): £10-12 from Screwfix or Amazon UK. It provides excellent coverage and dries in 20 minutes
• Halfords plastic primer: good adhesion on PLA at about £9 a can
• Citadel Chaos Black / Grey Seer spray: expensive at about £14 from Hobbycraft or Games Workshop, but well suited to 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

Painting offers 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) work well on 3D prints. Their matt black and metallic ranges are popular in the cosplay community. Montana Gold spray paints offer higher quality but cost around £6-8 per can.

Use the same technique as priming: light passes from a distance of 20-25cm and multiple thin coats. Three coats give solid coverage on most colours. Metallics often need four.

Brush Painting

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

Paint options:

• Citadel Base Paint (Averland Sunset) (Games Workshop): a strong base paint for miniatures, available at Hobbycraft and GW stores. One 12ml pot costs £4-6
• Vallejo Model Color Set (16 Basic Colours): my favourite option. The set costs £28-33 and contains 16 dropper bottles of 18ml each for controlled thinning and basic colour mixing
• 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. Two thin coats usually look smoother than one thick coat. Add a drop or two of water until the paint flows off the brush smoothly
• Use a wet palette made from a piece of baking parchment over a damp sponge in a lidded plastic container. It keeps paint workable for hours
• Base coat first (darkest colour), then layer up to highlights
• For miniatures, washes add depth quickly. Citadel Nuln Oil or Agrax Earthshade settle into recesses and create instant shadows. A £5 pot of wash is one of the most effective additions to a painting kit

I painted a set of D&D miniatures for my brother’s birthday last year. The materials cost about £18 for a pot of Nuln Oil, three Citadel base paints, and a cheap brush set. He thought I’d bought them pre-painted.

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

Apply two thin coats. Let the first dry fully (at least an hour) before the second. Work in a warm, dry space because cold or humid conditions can make clear coat turn cloudy, an effect called “blushing.” I ruined a painted Boba Fett helmet by clear-coating it in my garage in November. The finish went milky white, so I had to strip and repaint it. Do it indoors.

Material-Specific Notes

PLA

PLA is the most common printing material and generally the easiest to paint. It sands well, accepts primer evenly, and has no solvent sensitivity with acrylics. The main risk is heat. PLA softens above 55-60°C, so don’t leave painted parts on a sunny windowsill or in a hot car. The paint won’t prevent warping.

ABS

ABS is tougher to print but arguably better for painting. It is more heat resistant, can be smoothed with acetone, and takes spray paint without issues. ABS is the preferred material for cosplay armour for these reasons.

PETG

PETG sits between PLA and ABS. It is harder to sand because it is gummier, but it takes paint well once primed. It can’t be smoothed with acetone. PETG is a good choice for painted functional parts because it is tougher than PLA.

Resin Prints

Resin prints have much finer detail and virtually no layer lines, making them ideal for painting. Wash and cure them fully before painting, give them a light sand with 400 grit, prime, and paint. Resin miniatures look excellent with a proper paint job because much of the detail is already present straight 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. Allow 20 minutes between primer coats, 30 minutes between paint coats, and an hour between clear coats.

What You’ll Spend

A full painting setup for a beginner costs:

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

The setup isn’t cheap, 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 because each plastic behaves differently under primer and paint.

Is it worth it? If you’ve ever looked at a grey PLA print and thought “that’d look incredible in copper,” the answer is absolutely.