3D printed models are excellent canvases for custom paint jobs. Whether you are painting a fantasy display piece, gaming accessory, creature, terrain piece, or decorative model, a few simple preparation and painting techniques can make an enormous difference in the final result.
Many of our monochrome models at Nexus PC Works and Games are printed in light gray PLA intentionally. Light gray makes sculpted detail easy to see, photographs well, and provides a neutral starting point for customers who want to paint and customize their model.
What You Will Need
- Mild dish soap and water
- Soft brush or toothbrush
- Fine-grit sandpaper or sanding sticks
- Optional filler or modeling putty
- Primer suitable for plastic
- Acrylic paints
- Several brushes, including a medium brush and a small detail brush
- Optional washes, inks, or contrast-style paints
- Optional airbrush
- Clear matte, satin, or gloss sealer
1. Inspect and Clean the Print
Before painting, inspect the model for loose strings, small support remnants, rough spots, or other imperfections. Remove these carefully with flush cutters, a hobby knife, or fine sanding tools.
Wash the model with mild dish soap and lukewarm water, then rinse it thoroughly and allow it to dry completely. Cleaning removes dust, skin oils, and residue that can interfere with primer and paint adhesion.
2. Decide How Much Surface Preparation You Want
FDM printing creates visible layer lines. On a detailed model, those lines are often subtle enough that many painters simply prime and paint the piece. If you want a smoother display-quality finish, lightly sand the most visible surfaces before priming.
Start gently with a relatively fine grit and avoid aggressive sanding around small details. PLA can soften if it gets hot from friction, so light pressure is better than fast, heavy sanding.
Filling Layer Lines and Seams
For larger gaps, seams, or especially visible layer lines, use a model filler or putty that is compatible with plastic. Apply only what you need, let it cure fully, and sand it smooth. You do not need to eliminate every layer line for a good-looking painted model.
3. Prime the Model
Primer gives acrylic paint a more reliable surface to grip and helps reveal areas that may need additional cleanup. Use a primer intended for plastics or miniatures and follow the manufacturer's safety and application directions.
Apply multiple light coats rather than one heavy coat. Heavy primer can fill fine sculpted details. Let each coat dry as directed before adding another.
What Primer Color Should You Use?
- Gray: the most versatile choice and an excellent all-purpose starting point.
- Black: useful for dark, metallic, grim, or heavily shadowed schemes.
- White: useful for very bright colors, pastels, and vivid fantasy schemes.
Our light-gray PLA is already helpful for seeing details, but it should still be primed before a serious paint job.
4. Choose Your Paint
Water-based acrylic model and miniature paints are a dependable choice for PLA models. Craft acrylics can also work, especially on larger pieces, but thicker paints may need to be thinned so they do not hide fine texture.
A good rule is to use several thin coats instead of trying to get complete coverage in one heavy coat. Thin coats preserve details and usually produce a smoother finish.
5. Apply the Base Colors
Start with the largest color areas. Do not worry about every tiny edge at first. Establish the main colors of the model and let each coat dry before deciding whether another coat is necessary.
If a model has recessed areas that will eventually be very dark, painting those areas early can make later cleanup easier.
6. Add Shadows With a Wash
A wash is a thin paint designed to flow into recessed areas. It can quickly emphasize cracks, scales, stone texture, armor panels, fur, folds, teeth, wood grain, and other sculpted detail.
Apply the wash where you want deeper shadows and prevent large pools from drying on flat surfaces. Once dry, the sculpted details should appear more defined.
7. Bring the Details Back With Dry Brushing
Dry brushing is especially effective on 3D printed models with lots of raised texture. Put a small amount of lighter paint on a brush, wipe most of it off on a paper towel, and lightly drag the brush across raised surfaces.
The remaining paint catches edges and high points, producing quick highlights on stone, scales, fur, armor, wood, bone, and similar textures.
8. Paint the Fine Details
After the base colors, shadows, and highlights are established, move to smaller details such as eyes, teeth, runes, buckles, gems, trim, weapons, control panels, or other accents.
A small brush helps, but good brush control matters more than using the tiniest brush available. Keep the paint reasonably thin and take your time.
9. Optional: Use an Airbrush
An airbrush is not required, but it is useful for smooth gradients, large surfaces, glowing effects, atmospheric shading, and fast base coating. Airbrushing works particularly well on larger 3D printed pieces.
If you are new to painting, traditional brushes are completely capable of producing excellent results.
10. Correct Mistakes as You Go
Most acrylic painting mistakes are easy to fix. Let the area dry, repaint it with the underlying color, and try again. There is rarely a reason to strip an entire model because of a small mistake.
11. Seal the Finished Model
Once the paint is completely dry, a clear protective sealer can help protect it from handling and wear.
- Matte: reduces shine and is a common choice for figures and terrain.
- Satin: provides a slight sheen and works well for many display pieces.
- Gloss: creates a shiny finish and is useful for wet surfaces, gems, polished armor, eyes, or special effects.
You can also seal the entire model with matte or satin finish and selectively brush gloss varnish onto areas that should look shiny.
A Simple Beginner Painting Recipe
- Clean the print and remove any obvious rough spots.
- Apply light coats of gray primer.
- Paint the major areas with acrylic base colors.
- Apply a darker wash into recesses.
- Dry brush raised surfaces with a lighter version of the base color.
- Paint small details.
- Let the model dry completely.
- Apply a clear protective sealer.
This straightforward process can produce very good results without requiring advanced equipment.
Common Problems and How to Fix Them
Paint Is Not Sticking
Make sure the print is clean, dry, and properly primed. Oils and dust can interfere with adhesion.
Details Are Disappearing
Your primer or paint may be going on too heavily. Switch to thinner coats and allow them to dry between applications.
Layer Lines Are Too Visible
Lightly sand the most visible areas and use filler where needed before priming again. Texture-heavy designs often hide layer lines naturally once washes and dry brushing are applied.
The Finish Looks Chalky or Rough
Paint may be too thick, drying on the brush, or being applied over a surface that is not fully dry. Thin the paint appropriately and work in controlled coats.
The Model Looks Flat
Add contrast. A darker wash creates shadows, while dry brushing or edge highlights bring raised areas forward.
Why We Use Light Gray for Many Monochrome Prints
Light gray is a practical color for an unfinished model. It shows the sculpted detail better than very dark filament, avoids the harsh brightness of white, and lets you clearly see the surface while preparing and painting. It also gives customers a clean neutral model if they prefer to display it without painting.
Filament color is not a replacement for primer, but light gray makes an excellent starting point for inspection, preparation, and customization.
Take Your Time and Make It Yours
There is no single correct way to paint a 3D printed model. Some people enjoy highly detailed display finishes, while others prefer quick tabletop techniques or simple color schemes. Start with the techniques that fit your project and add complexity as you become comfortable.
Ready to choose a model? Browse our 3D Printed Products and look for models that would make a great painting project.
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