3D printing with PLA filament produces durable parts with a smooth, glossy finish. While the natural white or colored PLA prints look great, you may want to paint your prints to achieve more vibrant colors, unique designs, or improved aesthetics.
Painting PLA is easy with the right preparation and paints. This comprehensive guide covers everything you need to know to get professional painted results on your PLA 3D prints.
Why Paint PLA Prints?
Here are some of the top reasons for painting PLA 3D printed parts:
- Custom colors – Only a handful of natural PLA colors are available. Painting opens up endless color options for your prints.
- Detailed designs – Painting allows you to add intricate designs, textures, logos, letters, and images to your prints.
- Smooth finish – A coat of paint can hide the layer lines on prints for a perfectly smooth surface.
- Improved durability – Paint forms a protective barrier that improves the part’s durability and longevity.
- Professional appearance – Painted prints have a high-quality, commercial appearance.
Preparing PLA Prints for Painting
Proper preparation is crucial for the paint to adhere correctly to the PLA print surface. Here are the key steps:
Clean the Print
PLA prints should be washed in warm, soapy water to remove any oil, dust or residue from the print process. Allow the print to fully dry before painting.
Sand the Surface
Lightly sanding the surface with fine grit sandpaper improves paint adhesion by creating microscopic divots for the paint to grip onto. Start with 220 grit and work up to 600 grit for the smoothest finish.
Prime the Print
Priming fills in any small crevices on the print and provides a uniform surface for the paint to stick to. Spray primer designed for plastics works best. Do 2-3 thin coats allowing drying in between.
Sand Between Coats
Gently sand again with 600 grit after priming to remove any primer bumps for the smoothest final surface.
Choosing the Right Paints for PLA
PLA has a smooth, non-porous surface that can be tricky for some paints to adhere to. Follow these tips for selecting the right paint for your PLA prints:
- Acrylic paint – Acrylics bond extremely well to PLA and provide vivid color choices. They can be thinned with water for airbrushing.
- Spray paint – Aerosol spray paint formulated for plastics will provide great coverage on PLA. Enamel, acrylic, and lacquer sprays all work.
- Model/hobby paint – Enamel model paints are designed for painting plastic models and adhere great to PLA prints.
- Epoxy paint – Two-part epoxy paints provide the most durable finish for high-use prints.
- Avoid – Oil-based paints and many craft paints don’t properly bond to the slick PLA surface.
Painting Techniques for PLA 3D Prints
Once you’ve prepped and primed the print, you can apply your choice of paints in different ways:
Brush Painting
Use a small brush for details or a wider brush for larger surface areas. Acrylic and enamel paints brush on easily. Thin the paint slightly with water or solvent for smooth brush strokes. Do multiple thin layers, allowing drying time between coats.
Spray Painting
Spraying provides quick, full coverage on prints. Hold the can 6-10 inches away and do light coats using a side-to-side sweeping motion. Allow paint to fully dry between coats for best results.
Airbrushing
For professional results, use an airbrush to apply thinned acrylics or lacquers. Airbrushing allows blending colors and creating smooth color transitions and gradients. Use low airflow and keep the airbrush 6 inches away for optimal spray control.
Hand Painting
For small details, hand paint designs using a small brush and acrylics. Water down the paint slightly for easier application. Let each section fully dry before moving on to avoid smudging.
Paint Pens
These markers contain paint instead of ink, allowing coloring directly on the PLA print. Paint marker brands like Posca and Sharpie provide opacity and vibrant colors.
Weathering Effects
Create worn, rusty, or dirt-covered effects by dabbing on thinned acrylic paints in brown, silver, black, and rust colors. Remove some color with a rag for a distressed look. Apply a matte clear coat to seal the weathering effects.
Clear Coating PLA Prints
A clear coat will protect your painted prints from wear, sunlight, and moisture. Here are some top options:
Matte Clear Coat
Use a matte spray clear coat for a non-reflective, smooth finish. Matte protects painted prints while retaining the original quality of the paint color underneath.
Gloss Clear Coat
A gloss clear coat gives painted prints a shiny, wet-look finish. The high gloss accents the vividness of the colors. Gloss coats are more resistant to scratches and mars than matte.
Epoxy Resin
Brushing on a layer of epoxy resin provides the most durable clear finish. Epoxy adheres well to PLA and creates a glass-like coating that fully protects the paint. Consider epoxy for highly handled prints.
Polyurethane
Water-based polyurethane can be brushed on as a clear topcoat to add mild protection and Sheen. While not as durable as epoxy, polyurethane is quicker and easier to apply.
Painting PLA Print: Step-by-Step Tutorial
Follow these steps to paint your PLA 3D prints like a pro:
Supplies Needed
- PLA 3D printed part
- Sandpaper – 220, 400, 600 grit
- Primer for plastic
- Paint – acrylic, enamel, spray paint
- Clear coat – matte, gloss, or epoxy
- Small paint brushes
- Paper towels
- Water cup for thinning paint
Steps
- Wash the printed part with soapy water and let fully dry.
- Lightly sand print with 220 grit sandpaper.
- Upgrade sandpaper to 400 grit and 600 grit for a smoother finish.
- Clean part with a tack cloth. Apply 2-3 thin coats of plastic primer, allowing drying time between coats.
- Sand again lightly with 600 grit sandpaper once primed.
- Paint with your choice of acrylic, spray paint, airbrush, markers, or other method. Do multiple light coats for full coverage, allowing paint to dry between coats.
- For glossy designs, paint the recessed areas with gloss acrylic paint. Let dry fully.
- Paint over the entire part with matte paint for a professional contrasting finish.
- Once main paint is fully dry, optionally add weathering and detailing with thinned paints.
- Seal and protect the painted print with a clear matte, gloss, or epoxy coat.
With the right preparation and painting techniques, you can achieve stunning results painting your PLA 3D printed creations. Painting opens up a whole new world of design possibilities for your prints. Follow this guide to get started painting like a pro!
