How to paint 3D prints – PLA, ABS, ASA and other materials

A 3D print does not have to remain in the original colour of the filament. With the right paint system, you can create a smooth solid-colour finish, a strong pearl effect, Chameleon / Flip-Flop, Candy or other special-effect finishes. The most important part is choosing the surface preparation according to both the material and the desired result: do you want to preserve fine printed details, or remove visible layer lines and create a perfectly smooth surface?

In this guide, we will focus mainly on PLA, ABS and ASA, while also explaining the basic differences when painting PETG, resin prints and other materials.

Can 3D prints be painted with automotive paints?

Yes. Many common 3D-printing materials can be successfully coated with solvent-based paints after suitable preparation. We have also tested the compatibility of PMcolours paints with standard PLA in practice.

It is important to distinguish between two things:

• paint adhesion to the plastic,
• the surface quality of the print itself.

Paint may adhere extremely well to a 3D print while still leaving visible layer lines, support marks or other surface imperfections. A glossy clear coat can even make these imperfections more noticeable. For this reason, it is useful to decide before painting what kind of finish you want to achieve.

Two approaches: preserve details or create a perfectly smooth surface?

1. I want to preserve as much detail as possible

On figures, models, cosplay parts, reliefs or complex technical components, fine details can be more important than completely removing the printed layer structure.

In this case, applying a heavy filler coat automatically is not always a good idea. Filler can partially cover fine reliefs, lettering, textures or sharp edges.

For a clean, well-printed part, it is often enough to:

1. remove supports and any burrs,
2. clean the surface,
3. lightly scuff it if necessary,
4. apply several thin coats of colour,
5. finish with a clear coat.

For lightly scuffing complex surfaces, an ultra-fine 3M Scotch-Brite MX-HP hand pad is very practical. Unlike conventional sandpaper, it follows curves, edges and fine details well. Its purpose is not to remove the printed layers, but simply to create an even matt surface.

2. I want a smooth surface without visible layer lines

If you want the finished print to look more like a painted automotive or industrial component, more time needs to be spent on surface preparation.

A typical process may look like this:

sanding → filler primer → sanding → additional filler primer if required → final sanding → colour → clear coat

For filling minor surface imperfections, you can use products such as HB Body P360 2K Grey Filler Spray.

Filler primer is not a mandatory step when painting 3D prints. Use it where you genuinely need to level the surface. On finely textured or highly detailed models, leaving the filler out completely may be the better option.

How do different 3D-printing materials compare?

PLA: is plastic primer or filler necessary?

Not necessarily on standard PLA.

In our practical test, we applied a PMcolours pearl basecoat directly onto a standard black PLA print. The surface was not sanded or scuffed beforehand, and we did not use either plastic primer or filler.

After the first coat, there was no visible negative reaction between the PLA and the solvent-based paint. Even one thin coat created a strong pearl effect. After the second coat, the effect was fully developed.

Once dry, we carried out a simple practical adhesion test. The paint could not be pulled off using ordinary adhesive tape and showed very good adhesion to the surface. Finally, we finished the complete paint system with a 1K clear coat. Again, the PLA showed no visible damage or other adverse reaction.

Important: This test applies to the specific standard PLA filament used. The term PLA does not guarantee that every filament has the same formulation. SILK, MATTE, PLA+, Tough PLA and filaments containing wood, carbon, metallic particles or other additives may have different surface properties.

For a different or unknown filament, we therefore recommend carrying out a test spray first on an offcut, a test print or a hidden area of the part.

Should PLA be scuffed before painting?

Yes, even though the paint adhered very well to untreated standard PLA in our test.

For a more repeatable general procedure, we recommend lightly scuffing smooth surfaces. Aggressive sanding is not necessary. On a complex print, a fine Scotch-Brite pad is often more suitable because it reaches curved areas without significantly damaging small details.

After scuffing, remove all sanding dust. If you use a degreasing product, it should be compatible with the type of plastic being painted. With an unknown material, test the cleaner on a hidden area first.

You can also find general surface-preparation information in our guide How to Prepare the Surface Before Painting.

ABS and ASA: direct painting or plastic primer?

ABS and ASA can normally be painted successfully after proper cleaning and preparation. In practice, both direct application onto the prepared material and the use of an adhesion primer can work well.

If you want to increase the margin of safety for adhesion, particularly on parts exposed to more wear, you can use BOLL Plastic Primer before applying colour.

Plastic primer is not a filler. It is applied only as a thin adhesion-promoting coat and is not intended to level printed layer lines.

Smoothing ABS and ASA with acetone

ABS and ASA offer another interesting option: chemical smoothing with acetone. The surface is carefully softened so that individual printed layers can blend into a much smoother finish.

This can produce a significantly smoother part without applying heavy filler coats. However, chemical smoothing can also round off sharp edges and reduce fine details, so it is not suitable for every print.

Before painting, all acetone must be fully evaporated from the surface. Work only in a well-ventilated area and keep away from flames and ignition sources.

When should filler be used?

Use filler when you want to remove or significantly reduce the visible printed texture.

Typical applications include:

• large flat areas with visible layer lines,
• support marks,
• small depressions and surface imperfections,
• joints between several printed parts,
• projects where you want a smooth, painted finish.

On figures, engravings, textures or fine technical details, it may be better to leave filler out completely or use it only locally.

Which PMcolours paints can be used on 3D prints?

Once the surface is prepared and compatible with the coating system, it can be treated much like any other paintable substrate. The final effect is then mainly determined by choosing the correct base colour.

Pearl effect paints

PMcolours Pearl Effect Paints are particularly interesting on 3D prints because their appearance changes with both light and the shape of the object. On a complex 3D model, individual surfaces sit at different angles, making the pearl reflections especially noticeable.

For our PLA test, we used Interference Pearl AMETHYST Violet. Just two very thin coats produced a strong pearl effect without filling in the printed surface detail.

With effects designed for a black base, it is important to have an even, consistent background colour. On a black print, the filament itself may visually provide the dark base required. However, for the most uniform and predictable result, use PMcolours Black 1K Basecoat.

Chameleon / Flip-Flop

Flip-Flop effect paints, also commonly referred to as Chameleon paints, change colour depending on the viewing angle. Complex 3D prints are particularly suitable for this effect because different parts of the model reflect light from different angles.

For a standard Flip-Flop finish, use a uniform black base followed by several very thin coats of the effect paint and finish with a clear coat. Full instructions are available in our guide How to Apply Flip-Flop Paint – Complete Guide.

Candy

Candy paints are transparent, so they should not simply be sprayed directly over any filament colour. Their characteristic depth is created together with a reflective base.

For a classic Candy effect, we recommend first creating a uniform base and then applying SilverTouch Pearl Silver Basecoat. This is followed by thin coats of transparent Candy paint and finally a clear coat.

Surface preparation is especially important with Candy. Because the colour is transparent, imperfections, differences in the base or uneven application may remain visible in the final result.

Candy Pearl, Ghost Pearl and other effects

Candy Pearl, Ghost Pearl and other PMcolours effect systems can be used on 3D prints in the same way. Always follow the recommended base colour for the particular effect.

On complex shapes, several thin coats are preferable to one heavy coat. This helps preserve edges, reliefs and fine printed details.

Is a 1K clear coat enough for a 3D print?

For most normal hobby applications, yes.

For figures, decorations, models, prototypes, cosplay props or other parts that are not exposed to high mechanical or chemical stress, a quality 1K clear coat is usually a very practical option.

A clear coat:

• protects the effect layer,
• increases gloss or determines the final matt level,
• enhances the depth of pearl and other effect pigments,
• makes the finished surface easier to clean.

In our standard PLA test, we applied a 1K clear coat over two thin coats of pearl paint. Neither the PLA nor the coloured layer reacted negatively, and the clear coat noticeably increased the depth of the pearl effect.

A 2K clear coat is more appropriate where greater hardness and resistance are required, for example on frequently handled parts, exterior components or surfaces exposed to chemicals or higher mechanical wear.

Always follow the flash-off time of the specific effect paint and the application instructions for the chosen clear coat.

A glossy clear coat can make layer lines more visible

A surface that appears almost smooth before painting can show more texture after a glossy clear coat is applied. Gloss creates sharper reflections, which can make small waves or layer lines more noticeable.

This is not a defect in the colour or clear coat. If you want a genuinely smooth high-gloss finish, the printed layers need to be removed or levelled during surface preparation.

If a slight 3D-printed texture does not bother you, there is no reason to hide it with filler at all costs. A thin paint system preserves more detail and makes the entire painting process much simpler.

Simple recommended process for standard PLA

1. Remove supports and any burrs.
2. Clean the print thoroughly to remove dust and dirt.
3. Lightly scuff smooth areas with a fine Scotch-Brite pad if required.
4. If you want to remove visible layer lines, sand the surface and use filler if necessary.
5. Carry out a test spray on any non-standard filament.
6. Apply the correct base colour if required by the chosen effect.
7. Apply several thin coats of the effect paint according to the product instructions.
8. After sufficient flash-off time, apply a 1K or 2K clear coat depending on the required durability.

Common mistakes when painting 3D prints

• Trying to hide layer lines using colour alone. Basecoat is not filler and will not level larger imperfections.
• Applying coats too heavily. This can fill in small details and increase the risk of runs.
• Using filler over very fine reliefs. Details you want to preserve can be permanently reduced.
• Painting an unknown filament without testing it first. Additives in SILK, PLA+, filled or other specialist filaments can change the surface behaviour.
• Poor preparation of resin prints. They must be properly washed and fully cured before painting.
• Using the wrong base colour. Flip-Flop, Candy, Ghost Pearl and other effects require the correct background colour.
• Expecting a perfectly smooth gloss finish without preparing the surface. Clear coat protects the surface and enhances the colour, but it does not remove layer lines.

FAQ – painting 3D prints

Do I need plastic primer on PLA?

Not always. In our practical test on standard PLA, PMcolours basecoat showed very good adhesion even without primer. However, filament formulations vary, so we recommend a test spray when using a different PLA. Lightly scuffing the surface can provide an additional margin of safety for adhesion.

Do I need to use filler before painting?

No. Filler is mainly useful when you want to remove printed layer lines or other surface imperfections. If preserving fine details is more important, leaving filler out may be the better choice.

How many coats of paint do I need?

This depends on the specific colour and effect. In general, several thin coats are better than one heavy coat. In our test with violet pearl over black PLA, a very strong effect was already achieved with two thin coats.

Is a 2K clear coat necessary on a 3D print?

For ordinary decorative models and hobby projects, usually not. A 1K clear coat is generally sufficient. We recommend 2K clear where maximum hardness and mechanical or chemical resistance are priorities.

Can I smooth ABS or ASA with acetone before painting?

Yes. Acetone smoothing can significantly reduce the visibility of printed layers on ABS and ASA. However, it can also round off sharp edges and reduce fine details. Before painting, the solvent must have fully evaporated from the material.

Can SILK or other specialist PLA filaments be painted?

Most likely, but results can vary depending on the manufacturer and additives used. SILK, MATTE, PLA+, carbon-filled, wood-filled and other modified PLA filaments should therefore be tested on a small sample first.

Summary

3D printing works very well with PMcolours paints. The key is not to use one universal preparation method for every type of print.

If you want to preserve fine details, keep the coating system as thin as possible and use filler only where it is genuinely needed. If you want a perfectly smooth surface, spend more time sanding, levelling the printed layers and applying filler where necessary.

In our practical test on standard PLA, we confirmed very good compatibility with PMcolours pearl basecoat and a 1K clear coat even without primer. With modified filaments and other materials, however, we always recommend a small test spray first.

Whether you choose a pearl finish, Chameleon / Flip-Flop, Candy or another special effect, just a few thin coats can transform an ordinary 3D print into a striking finished part while preserving the details built into the original model.