How to Paint Gradients with Spray Paint On Gunpla

While a gradient might be easier to achieve with an airbrush, there’s no need to scratch out your plans for a custom paint job if all you have are cans of spray paint. Contributor Marc Rivera details his method for achieving a gradient with spray paint.

After reading and re-reading articles on how to properly spray paint Gunpla, I finally decided to take the plunge and paint my first kit. I decided that my first painted Gunpla would be the FG Zaku II. But this wouldn’t just be some MS-06F Zaku II: Marc Rivera’s Custom with a palette swap of the standard grunt we all know and love. No, instead, I set my sights on replicating the look of one of my favorite Gundam artworks of all time.

I would be making my own camouflaged Zaku, meant to blend in—I mean, as much as a giant robot can—in the desert. Of course, this was still my first build, so I wanted to keep things simple. The kit would just be painted light sand the waist down, and sky blue chest up. As an extra touch, I decided to paint the top part of the kit light sand, as otherwise, it would stand out when seen from above. Of course, if I simply painted the top of the kit to look completely like sand, the illusion of the sky camouflage would be ruined! 

After a bit of pondering and experimenting while testing the paints on some spoons, I figured out a way to easily and consistently create a gradient using spray paint. While this gradient typically looks different from the smooth kind created by the application of thinned paints through an airbrush, this dot gradient is still nice to look at.

Just like spraying painting a kit normally, you’ll need:

• The Gunpla (I’ll be using the SDCS Char’s Zaku II). I find this technique is easier with kits that have larger pieces, like SD kits.
• Primer. (Learn how to prime your kits here). I used Tamiya Surface Primer Grey.
• Spray Paint. I used one can each of Tamiya Light Sand and Tamiya Light Blue.
• Masking Tape. This is optional for larger pieces, but may be necessary if the piece you’re trying to apply a gradient to is small.

First, you’ll want to cut the pieces of the kit out of the runners with side cutters or nippers. If there are imperfections (like stress marks), feel free to use auto sandpaper (we recommend a superfine variety like 400 grit) to smooth down the parts—since you’ll be painting the kit, scuff marks from sanding will be hidden later. Next, you’ll want to wash the parts to remove the oil from your fingertips that could keep the paint from sticking to them. We recommend dunking them in a bath of lukewarm water with 1 teaspoon of dish detergent. Once the parts fully air dry, you can put them up on painting sticks. 

After you’ve finished priming the pieces, it’s time to kick this tutorial into motion. Start by spraying the paint that will make up the majority of the piece’s color. This is the color that you want the gradient applied to. While painting, be sure to follow along with our Tips For Spray Painting Gunpla guide by Otaku Dan and spray lightly. It’s better to have to spray a second round of paint than to have to deal with a gooey, overapplied mess!

Be sure to spray from every angle except the direction you want to apply the gradient from. As you can see in the photo, I want the light sand gradient coming down from the top of the head, so I left the center of the head unpainted.

Once you’ve let this first coat of paint dry (after about 10 minutes, give or take), next comes the gradient! It’s effectively the same process as before, except you’ll only want to spray from the direction you didn’t before. Make sure to cover all of the portions where the primer is still visible. Since the spray from a can of paint is typically far wider than that of an airbrush, this will create a natural gradient as you cover the unpainted areas.

Tips

While that’s the gist of it, here are some tips in case you’re having difficulty with painting:

• Be sure to keep your coats light and thin! If you apply too little you can correct it later, but if you apply too much, especially when you’re applying your gradient, it can result in some undesired effects. These can range from a noticeable difference between the two colors due to paint thickness to covering up the piece’s panel lines.
• If the piece is too small and you think you’d be unable to leave any part unpainted in the base coat, try covering the piece with some masking tape. Don’t try masking when applying the gradient though, as this will cause the gradient to stop suddenly (if you like how that looks, go ahead! Gunpla is Freedom!).
• Make sure you have enough paint for the coat you’re applying! If you run out of paint then it’ll create splatters rather than a gradient. I didn’t pay attention when spraying the lower half of the SD Zaku’s chest, and now it looks less like a smooth color change and more like a Jackson Pollock painting.

That’s all there is to it! After a bit of practice, you’ll be able to create a gradient with a spray can. Still, this guide comes with a caveat: since you can’t control the size and ratio of paint to thinner, this gradient won’t have the same smoothness one could achieve with an airbrush. But if you don’t have space, money, or you simply don’t want to get an airbrush, this is an excellent method to create some smooth shades with your Gunpla.

Marc first got into Gunpla with the HG Zaku II, which he thought had a really cool looking box. He knew nothing about Gundam back then, but since that kit, he’s gotten very familiar with the series. You can find him occasionally posting progress pictures of SD Zaku featured in this article on his Twitter @official_marc_r.