How to Sand, Prime and Paint 3D Prints

Coloring 3D prints can create a perfect final surface, making them more attractive. For most beginners, the paint job may seem complex, involving steps like sanding, priming, mixing colors, painting, and finally sealing. In fact, painting 3D prints is a relatively easy and delightful process. We will guide you step by step on how to sand, prime, and paint your 3D prints. Most of the tools mentioned in this article can be found in the Anycubic 3D Printing Painting Kit.

CONTENTS

1. Preparation before Sanding, Priming, and Painting
2. Steps for Sanding, Priming, and Painting 3D Prints

• Step1: First sanding
• Step2: Preparation before primer
• Step3: Primer
• Step4: Second sanding (optional)
• Step5: Color mixing (optional)
• Step6: Painting
• Step7: Varnishing

3. How to Clean and Maintain Paint Brushes
4. Video Tutorial

Before starting sanding, it's essential to clean the part, cure it, and remove supports. Then, don't forget to put on your protective gear, such as gloves, safety goggles, and a respiratory mask. This gear helps prevent dust from entering your eyes and respiratory system, as sanding releases particles.

Materials and tools you'll need:

(Anycubic 3D Printing Painting Kit)

Step 1: First Sanding

Remove rafts and supports from your 3D part with a flush cutter to trim most of the supports, and use a craft knife for handling intricate areas. Removing the supports may leave numerous marks and bumps, so hand files can help in sanding down the large support marks. Next, use sandpaper and sanding sponges to smooth the print surface. Finally, clean it with water and wipe off the dust particles with a cloth.

How to choose sandpaper grit

• <200 grits are used for rough sanding. But they may leave obvious scratches on the print surface.
• 200-500 grits are recommended for initial sanding. This can effectively remove noticeable imperfections in the parts.
• 600-800 grits are for further smoothing. This can achieve a truly fine and polished surface.

Step 2: Preparation Before Primer

Prepare a wet palette to prevent acrylic model paint from drying out. Pour water into it and place a sponge to absorb the water thoroughly. On top of the sponge, put a piece of tissue paper to enhance moisture distribution, and lastly, place your palette paper on top. Shake well before using the primer to ensure a uniform color.

If your printed object is relatively light and small, making it challenging to prime and paint, you can consider preparing a handle and securing it using blu-tack. It's advisable to test whether the object is firmly attached to the handle before applying primer. Otherwise, there's a risk of the object coming loose and falling.

Step 3: Primer

Paint primer serves as a base coat for the printed part, helping to fill in the layer lines and gaps on the print's surface, thus creating a smoother surface for the paint to adhere to. It's important to ensure that the part must be cleaned and dried, free from any oil, resin residue, dust, or other contaminants on the surface. You should apply a thin and even primer coat with a brush, and avoid repeatedly brushing over the surface when it's partially dry, as this can result in uneven paint on the model's surface. If you intend to apply an additional coat of primer, make sure that the surface is completely dry. Once the surface is dry, you can start further sanding or painting.

Step 4: Second Sanding (optional)

After the primer application, if you still find obvious imperfections on the print, you can do fine sanding again. If any primer comes off after sanding, recoating the primer.

Step 5: Color Mixing (optional)

Mixing basic acrylic paint colors can get a wide range of colors. For example, white is highly effective in adjusting the brightness of colors. By mixing white into dark or saturated colors, you can make them appear lighter and softer. However, the proportions of the color is the key to mixing. If you are new to this, mix in small increments until you achieve your desired color. Of course, we also provide some reference formulas for mixing colors, as shown in the image above. Use your imagination to discover even more colors.

Step 6: Painting 3D Prints

We come to a crucial step - painting your 3D prints. Start by dropping a small amount of paint into a palette to prevent it from drying out quickly. Next, dip your brush in water to moisten it, and then dry it with a cloth. Lastly, use the brush to apply the paint onto the surface of your printed part. If needed, masking tape can help protect surfaces you don't want to paint during the process.

More tips for painting:

• Apply the paint as thinly and evenly as possible. Do not rub back and forth when the surface is half-dry, which may cause uneven coating on it.
• When the first layer of paint is completely dried out, additional layers can be applied to enhance the coverage effect. Especially, light colors require several coats to achieve full color saturation.
• After squeezing out the paint, keep the bottle cap clean and cap it as soon as possible to stop the paint solidifying and blocking the tip.

Step 7: Varnishing 3D Prints

Varnish is a transparent material that, when applied to your 3D print, forms a glossy protective layer. It helps prevent moisture and dust from damaging the surface of the print. If the surface's paint is fully dry, applying a layer of protective varnish can extend the print's lifespan.

After finishing post-processing steps such as sanding, priming, and painting, it is essential to keep your tools and workbench clean at all times. This helps avoid paint contamination, extends the lifespan of your painting tools, and reduces the potential hazards related to chemicals.

If the brush is not used for more than 30 seconds, you should rinse it in a bowl of water immediately. Otherwise, the paint will cause the bristles to become too hard and dry to use. And do not soak the brush for a long time. After cleaning it with water, blot it on a paper towel or clean cloth.