For many Gunpla (short for Gundam plastic models) modelers, painting is one of the most exciting parts of the hobby. However, beginners may feel overwhelmed by all the different techniques and tools available. Using an airbrush can be a great way to achieve a smooth and even finish, but it can also be intimidating for those who have never used one before. On the other hand, you may be familiar with airbrushing models, but you’re not sure how to tackle painting a Gunpla, which can differ from what you may consider the normal painting process.
Let’s take a look at how you can get the most out of airbrushing your Gundam models no matter if you’re a beginner or an expert. And if you need help building your first Gunpla,
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For your first Gunpla painting project, I suggest a Master Grade (MG) kit. Bigger and more detailed than a High Grade (HG) kit, it will have more parts, which means more surfaces to apply paint, no masking, and less hand-painting — beginner friendly! I’m going to paint a Zeta Gundam 2.0 in basic colors and primarily use acrylic paints.
I have a spray booth for airbrushing, but that may not be where you are yet on your modeling journey. Make sure your workspace is clean and well-ventilated. You can make a spray booth out of a cardboard box. Cut a hole in the top for ventilation and light. Even with water-based acrylic paint, it’s a good idea to wear a mask and gloves.
Solvent-based paints
If you are spraying lacquers or enamels without a properly ventilated booth, move your work into your garage or other area outside your house and open the door. Wear a rebreather, neoprene gloves, and eye protection while painting. Position a fan to draw fumes outside, away from your work area.
Before painting, disassemble your Gunpla into its component parts — especially the armor because it is affected most by painting. This step allows you to paint each part separately and avoid getting paint on areas that shouldn’t be painted. Divide parts by colors. The inner frame can be disassembled by limbs.
Before painting, wash your Gunpla parts in a dish with a small amount of dish detergent and a soft toothbrush. This will remove oils and dirt that may interfere with paint adhesion. Do not use liquid hand soap because there may be additives that could interfere with paint. Rinse and pat dry with soft paper towel.
You’ll need alligator-clip sticks and a stand — a cat-scratcher board is a good alternative. Attach the clips to your Gunpla parts and insert the sticks into the board. These will allow you to handle the parts without touching them while painting and set them aside to dry.
To provide a smooth surface and improve paint adhesion, prime your Gunpla parts. I prefer spray-can primer because it’s fast. Hold it 5-8 inches away from the part and spray light, even strokes. Apply thin coats and wait for each layer to dry before adding another.
While the primer dries, prep your paints. I’m using Vallejo Mecha Colors, which are formulated for use with articulated model kits making it more durable and scratch resistant. For the basic Zeta Gundam colors I used Pure White (No. 69.001), SZ Red (No. 69.009), Blue (No. 69.019), Sand Yellow (No. 69.033) and Dark Grey Green (No. 69.041 ). In the mixing bottle I have a custom-mixed thinning sauce.
Thinning Sauce
To thin the paints for airbrushing, you’ll need Vallejo Airbrush Flow Improver (No. 71.262) and Airbrush Thinner (No. 71.261). I combine these together into a “thinning sauce” — 7 parts thinner to 3 parts flow improver — and keep it in a mixing bottle for use whenever I’m airbrushing.
For airbrushing you’ll need an air source and an airbrush. If you’re starting out, I recommend 1/5 horsepower compressor with a 3-liter tank, pressure valve, and water trap. For spraying these colors, I’m going to use an airbrush with a .4 nozzle, which will give good coverage and still provide control.
To thin your paint, I recommend using a small cup to mix paint and thinner outside your airbrush cup. I use a small glass cup and a metal stirring stick. The thinning ratio I use for most Vallejo Mecha Colors is 3:1 paint to thinner. You want a skim-milk consistency, and the paint should run off the stirrer smoothly.
Pour the thinned paint into the airbrush cup and set your air pressure to 20 psi. Hold the airbrush 6-8 inches away from your model and apply a thin, even coat of paint using a smooth, steady back-and-forth motion to cover the surface, overlapping each pass slightly.
My airbrush technique
I keep the airbrush constantly moving to avoid creating areas of heavy or uneven paint. My first coat is almost always a mist coat, which creates a buffer for the second coat to cling to. I build up the color over two or three coats, careful to achieve a smooth, even finish. To prevent paint from running or smearing, I let each coat dry completely before starting the next one.
And remember, light colors like yellow and white need more coats to build up the color. Naturally less opaque than other colors, white and yellow can seem almost transparent as they go on, allowing the base coat or primer to come through. A pink primer under yellow paint provides the perfect vibrancy, and gives an almost orange hint to the paint. If you don’t want that, white primer is best because it won’t change the shade of the yellow like gray or black, which will give the yellow a greenish hue.
For painting Mecha Color Sand Yellow, I thin at 6:1 paint to mixing sauce; this is because yellow is a bit more translucent than other colors. I want to be able to build a rich color affected less by the color of the underlying primer.
After you’ve completed your base coat, seal the paint with matt/flat, satin/semigloss, or gloss varnish (clear coat), depending on the look you’re going for. I’m using Mecha Color Gloss Varnish (No. 27.701), which will provide a smooth surface for decals and panel lining.
Let the varnish cure overnight in a dust-free area or put it inside a big plastic container to ensure no debris or dust gets trapped in the clear coat. When it’s dry, assemble your Gunpla limbs and weapons before applying decals. This tidies your workspace and prevents you accidentally losing small parts.
A tip about clear coats
If you plan to use water-slide decals, apply a gloss varnish to your model. The smooth surface will expedite decal application and minimize silvering (when the decal doesn’t adhere completely). After you’re finished with decals, you can go over the part with a matt or satin varnish for your preferred appearance.
Water-slide decals are a step up from the stickers that come in many Gunpla kits. Some kits come with both stickers and decals. If you don’t have decals, you can apply the stickers from the kit, buy aftermarket decals, or print your own on decal paper from a hobby or craft store.
An easy way to add visual interest and pop details is to flow paint into panel lines. For this, use black Tamiya Panel Line Accent Color (No. 87131). Flow the accent color into the panel lines with the provided brush and clean up excess with cotton swabs dampened with enamel thinner or mineral spirits. Yes, the accent color may go over some of the decals. That’s OK and expected!
Lastly, airbrush a topcoat of clear over the decals and panel liner. An overall clear coat ties together all of the work you’ve done, helps the decals appear painted on, and protects your paint job from dust and scratches. Let it dry, fully assemble the model, and proudly display your painted Gunpla!
Final Thoughts
Airbrushing your Gunpla can be a fun and rewarding way to take your modeling to the next level. By following these tips, you can achieve a smooth and professional-looking finish on your models. Don’t be afraid to experiment and practice with your airbrush and remember to always work in a well-ventilated area wearing appropriate safety gear. With practice and patience, you’ll soon be creating stunning and unique designs that truly stand out on your shelves. Happy building!