Smooth your print before painting
Paint doesn't hide imperfections; it actually highlights them. Every layer line and scratch will show through the paint. That’s why a great paint job always starts with a smooth surface.
First, remove any support material, sand the print smooth (start around 220 grit and work your way up to at least 400), and make sure it's dust-free. For a truly professional finish, fill deeper layer lines with filler primer.
You can find the full guide on sanding and smoothing in our blog how to smooth a 3D print. In this article, we assume your print is already smooth and clean, so we’ll focus on the priming and painting process itself.
Why primer is essential
The biggest mistake when painting a 3D print is applying paint directly to the bare plastic. Plastic is smooth and sometimes slightly greasy, which makes it hard for paint to grip. This results in an uneven coat that peels off the moment you touch it.
A primer (base coat) solves this. It acts as an intermediate layer that bonds well to the plastic while creating a slightly textured surface for the paint to grab onto.
Additionally, primer makes small imperfections visible so you can fix them before applying color, and a base coat ensures more vibrant colors and better coverage.
There are two types of primer you'll come across. A standard (plastic) primer is purely for adhesion and is applied in thin layers. A filler primer is thicker and also fills in small layer lines and sanding marks, which is ideal if your surface isn't perfectly smooth yet.
For most prints, a plastic primer suitable for plastic works just fine, such as the Edding 5200 at 123-3D.
Which paint should you choose?
There are two routes for 3D prints that both work well. Which one you choose depends on your print and how much control you want.
Acrylic paint with a brush
Acrylic paint is water-based, dries quickly, is easy to clean up, and comes in countless colors. Using a brush gives you a lot of control, making it the favorite for miniatures, details, and small prints. You work in thin layers and build up the color gradually.
The advantage is precision and low cost: you only need paint and a brush. The downside is that it's difficult to get a large, flat surface even with a brush. You're more likely to see brush strokes, and it takes more time than spraying.
Spray paint from a can
Spray paint (acrylic-based, suitable for plastic) provides the most even result on larger surfaces. In a few thin layers, you get a sleek, uniform finish without visible strokes. For a housing, a helmet, or a large decorative print, this is the fastest route to a great result.
The advantage is speed and an even coat. The downside is less control: with small details or sharp color transitions, it's easy to spray too much, and you need a ventilated area plus a mask. Masking tape helps to create sharp color boundaries.
In practice, many people combine both: spray paint for the base coat and large areas, and a brush for the details on top.
Step-by-step guide: how to paint your 3D print
Below is the complete process, assuming your print is already sanded smooth and dust-free.
- Clean and degrease. Wash the print with lukewarm water and a little dish soap, or wipe it down with isopropyl alcohol. This removes grease, dust, and fingerprints that ruin adhesion. Let it dry completely.
- Apply the primer. Spray or brush a thin, even layer of primer over the entire print. When using a spray can, keep a distance of about 20–30 cm and move steadily. One thin layer is better than a thick glob.
- Let it dry and check. After drying, you will see imperfections more clearly. Are there still layer lines or scratches? Sand them lightly (400 to 600 grit) and apply a second coat of primer if necessary.
- Paint in thin layers. Apply your color now, whether it's spray paint or acrylic. Always work in several thin layers rather than one thick one. Let each layer dry thoroughly before applying the next. Thin layers prevent drips and give a cleaner result.
- Finish the details. Use a fine brush for accents, or masking tape for sharp color edges.
- Protect with a clear coat. A final layer of varnish or clear coat protects the paint from scratches and wear, and determines whether your print ends up matte, satin, or glossy. This is especially recommended for prints that you handle often or keep outdoors.
Differences by material: PLA, PETG, and ABS
Not every filament is equally easy to paint. How well paint and primer adhere varies by material.
Painting PLA
PLA is by far the easiest to paint. After light sanding and a coat of primer, the surface is an excellent base, and both acrylic and spray paint adhere to it perfectly. Just keep one thing in mind: PLA softens around 55–60°C, so don't use any painting or drying methods that involve high heat. For most hobby prints, PLA is the least demanding choice.
Painting PETG
PETG requires more preparation. The surface is smoother and can be slightly greasy, making it harder for paint to grip. Therefore, degrease the print extra thoroughly with isopropyl alcohol and always use a primer suitable for plastic.
If you skip that preparation, there's a high chance of peeling. With the right primer, PETG is easy to paint; it just requires a bit more care beforehand.
Painting ABS
ABS is easy to paint and is actually the easiest of the three to sand. Just like with PETG, degreasing and using a plastic primer are important. An added advantage of ABS is that it can withstand higher temperatures, making it less sensitive during the drying process. Always work in a ventilated area, especially if you decide to smooth the ABS with acetone before painting.
Frequently asked questions about painting a 3D print
Can you paint a 3D print without primer?
You can, but it’s not recommended. Without primer, paint doesn't adhere well to smooth plastic, resulting in uneven coverage and peeling. A thin layer of primer takes little time and makes the difference between a professional finish and a disappointment.
Which paint adheres best to a 3D print?
Acrylic paint (water-based, for brushes) and acrylic-based spray paint both adhere excellently to a primed print. Acrylic paint is ideal for details, while spray paint is perfect for large, even surfaces. Avoid solvent-based paints that can damage the plastic, unless the packaging specifically states they are safe for plastic.
Do I need to sand my print before painting?
Yes, otherwise the print lines will be clearly visible through the paint. Light sanding improves both the smoothness and the adhesion of the primer. You don't need to sand to a high gloss: 220 to 400 grit is usually enough. You can read how to do that in how to smooth a 3D print.
Is a painted 3D print water-resistant?
Not automatically. Paint alone doesn't make a print waterproof, as water can still seep through the layer seams. A clear topcoat helps, but for truly waterproof results, you should look at the material and a proper coating. Read more about that in which filament is waterproof.
Which material is the easiest to paint?
PLA. It adheres without issues after sanding and priming and is the least demanding. PETG and ABS are also easy to paint, but require extra degreasing and a plastic primer for a lasting result.
Get your 3D print made
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