How to Prime Miniatures with an Airbrush (Tips and Guide)

---

Do You Need to Spray Primer for Best Results?

You don’t need to spray a primer to achieve the best results with your painted miniatures. Many miniature painters and artists use regular surface primers and apply them with a paint brush. My recommendation for non-spray, brush on primers are to use Vallejo Surface Primer or any other water-soluble polyurethane primer. This is because with these primers, you can use regular water to thin them down.

RELATED: TOP 10 RECOMMENDED PRIMERS FOR PAINTING MINIATURES AND MODELS

Applying primer with a brush makes you prone to applying coats that are too thick (among other common priming mistakes). By thinning your primer with water, it allows the primer to flow off your paint brush and will help you retain surface definition on your model.

Another alternatives to spraying a primer with an airbrush or using an aerosol primer is to use a thinned coat of gesso. Gesso is a traditional compound artists use for priming canvas and other surfaces in preparation for acrylic and oil paint. Most gesso come in thick pastes that you’ll need to thin with water if you’re using it on models.

The advantage of a gesso is that it dries with a matte, textured finish and has a liquid absorbent quality to it. This means a gesso will help paint stick to surfaces better and allow solvents contained in oil paints (which some artists use to paint miniatures) to evaporate.

Suffice it to say, you can use a regular brush to prime your models. It may be slower and a bit more effort, but if you’re careful, you’ll be able to achieve great results with your miniature painting without spraying a primer.

Best Airbrush for Priming Models?

I have several articles about airbrushes for painting miniatures, e.g., base coating, painting details, and more. In general, the best airbrush for spraying primer on miniatures is a gravity fed, double-action airbrush that has a nozzle opening of 0.3mm or larger. A smaller nozzle size will make your airbrush prone to clogging.

The two airbrushes I would recommend anyone use for spraying primer include the Badger Patriot 105 or an IWATA HP-CS. Both airbrushes are great for spraying thicker mediums, like primers or heavier body paints. These airbrushes give a lot of wiggle room to experiment and are not as prone to clogging as other airbrushes in their class.

Of course, the large nozzle sizes on the Patriot 105 or, to a lesser extent, the IWATA HP-CS will preclude some ability to spray finer detail. But, these parts are interchangeable if you decide you want to start airbrushing thinner media, like inks or washes.

RELATED ARTICLE: A COMPLETE GUIDE TO AIRBRUSHING MINIATURES AND MODELS

What’s Better? Aerosol or Surface Primer with an Airbrush?

Both aerosol primers (aka rattle can primers) and surface primers you use with an airbrush work well under the right conditions. Although both apply primer using an atomized spray application on your models, they have advantages and disadvantages you should know.

An aerosol primer is convenient. You buy a pressurized can, shake the primer to mix the solvent, open the cap, and spray your model with the nozzle held 6-12 inches away. Under the right conditions (e.g., room temperature or 25 degrees Celsius and relatively low humidity <50%), aerosol primers work great. The Tamiya spray primer is a gold standard for professional miniature painters and scale modelers everywhere.

The disadvantage of aerosol primers are mostly due to its temperament to ambient conditions. In cold weather, all aerosol primers and spray paints fail to work well. There are workaround hacks for spraying outdoors in cold weather. But, when the air is cold, spraying indoors with a spray booth or keeping the metal spray can warm while you work is the best practice.

In warmer climates, high relative humidity (>50-70%) is also a bad recipe for a good primer application (even with an airbrush). You can use a hair dryer or dehumidifier to reduce the moisture in the air to help you prime during humid climates.

The reason I prefer using an airbrush over aerosol primer is for safety reasons. Aerosol primers contain volatile solvents and produce harmful fumes that can hurt your lungs if you don’t ventilate the area well.

I also like using an airbrush for priming models because you have more control over where primer goes. An aerosol primer only has an on or off switch. On the other hand, an airbrush lets you control the amount of primer you’re spraying. You do this by adjusting the air pressure and the primer flow mix in the airbrush (more about this below).

Overall, I would highly recommend getting an airbrush only if you plan to use it for more than priming miniatures, or your ambient conditions for aerosol use is poor. For example, get an airbrush such as the Patriot 105 if you plan to paint your models with it, e.g., base coating, and you want to prime during the winter, cold months.

How to Prime Your Miniatures with an Airbrush (5 Steps)

Here are 5 simple steps for how to prime your miniatures and models with an airbrush:

The advantage of pre-mixing your primer before loading it into your airbrush is that you prevent any debris or particulates from clogging your airbrush nozzle. This may happen if you don’t mix your primer properly inside the airbrush paint cup.

There are purpose-made thinner additives for paints and primers you can use to make airbrushing easier and less prone to clogging. The only airbrush thinners I recommend and use is Vallejo Airbrush Thinner and Golden Airbrush Medium. Both are affordable, come in huge bottles, and lubricate the internal moving parts of your airbrush. They reduce paint clumping and improve flow through the nozzle. They also atomize well along with paint, so you’ll have a really fine mist you can control.

The proper consistency of primer for airbrushing your models is similar to the viscosity of whole milk. You can use the drip test. Using the back handle end of a paint brush, drag a bit of primer up the side of a cup. If a small droplet forms, then slides, this is the proper consistency. If no droplet forms (e.g., the primer runs down quickly), or the primer sticks to the side of the cup without moving, then the primer is too thin or thick, respectively.

Adjusting the air pressure for your airbrush can reduce problems with primer that is too thin or thick. But, at some point, it’ll be more trouble working with a poorly thinned primer.

What Air Pressure Should I Use for Priming Miniatures with an Airbrush?

The ideal air pressure for priming your miniatures with an airbrush is around 20-30 PSI. The proper air pressure you should use for airbrushing a primer, however, will depend on your airbrush nozzle size and the viscosity of the primer. The other variable you may want to consider with adjusting air pressure is how large of a surface you want to prime.

The larger your model, for example, the larger you’ll want your spray pattern. To spray a larger area, increase your air pressure and hold your airbrush farther back. The spray “cone” pattern will expand, allowing you to cover more surface quickly.

For smaller miniatures, reduce your air pressure and bring your nozzle closer. You may also want to further thin your primer to account for the lower air pressure and reduce the risk of clogging the nozzle.

Is Spraying Airbrush Primer on Miniatures Safe?

The safety of airbrushing depends on your health and ability to resist the risk of inhaling any of the oversprayed product. At the very least, make sure that whatever you spray through your airbrush has a non-toxic label. Although the non-toxic designation doesn’t preclude you from getting ill, it may reduce your chances of serious harm.

As mentioned above, don’t airbrush ammonia based products, e.g., cleaning fluids, or other surfactants, e.g., soapy mediums. If inhaled or ingested, they can do serious damage to your lungs and body. You can read more in this article about model paint product toxicity.

If you’re unsure about your personal safety while airbrushing, spray your models outside with an aerosol primer, or use a regular brush to apply a surface primer to your models. You can also use a airbrush spray booth.

I personally feel comfortable airbrushing Vallejo Surface Primer with proper ventilation and a spray booth. I’m also worry-free when it comes to using artist-grade airbrush thinners to reduce the viscosity of my model primers.

Vallejo Surface Primer is my favorite primer for almost any miniature paint job I do for commissions or for my collection of tabletop minis. It works great in an airbrush or applied with a regular brush. You can see how to use this primer on miniatures in this full review and guide.

2. Badger Stynylrez Primer

Badger Stynylrez is a very popular surface primer for miniatures. Like its direct competitor, Vallejo Surface Primer, Badger Stynylrez is a water-based acrylic polyurethane that airbrushes easily straight from the bottle. Use a suitable air pressure for your model application, e.g., 20-30 PSI, and an airbrush with a 0.3 mm sized nozzle for best results and less clogging.

Load the primer right into your airbrush unthinned, or a drop of water or thinner, and spray directly on your model. As with Vallejo Surface Primer, you can expect to wait up to 30-60 minutes for the primer to properly dry. To speed up the drying of any surface primer, you can use a hair dryer set on the lowest heat setting.

Both Badger Stynylrez and Vallejo Surface Primers work great on small miniatures and large model terrain pieces or vehicles. Use multiple thin coats to avoid applying primer on your model too thick. Thin layers of primer will help you retain surface detail on your miniatures.

Createx Colors Sealer (Primer) is a primer that I recommend to anyone planning to airbrush larger models or surfaces, e.g., RC cars, vehicles, or terrain pieces. As a water-based primer, Createx Colors Sealers provide a durable foundation coat that helps paint stick to model parts and pieces that undergo flexing or heavy handling. A limitation of these primers are that they are a higher viscosity fluid, e.g., thicker. They also have a dense, textured finish that can potentially obscure details on small scale models and miniatures.

I recommend using this primer for airbrushing large models and pieces and only with a higher air pressure (around 25-35 PSI). To avoid clogging, you should also only use airbrush nozzle sizes of 0.3mm or larger. You can certainly thin this primer using water or artist-grade airbrush thinner to help atomize the flow mixture.

Tangible Day on YouTube (Miniatures and More!)