Liquitex suggests using their Professional Acrylic Inks for airbrushing, which are brightly pigmented and ultra-fluid. These inks don’t require thinning, have minimal odor, and can be easily cleaned with water. If you opt for using their Soft Body colors as I do, Liquitex suggests thinning them first with their Airbrush Medium to achieve the desired consistency. What follows are my notes using the Soft Body colors in my airbrush.
Safety First
Safety should never be compromised. Always work in a well-ventilated area and wear a full face mask with an organic vapour filter to avoid inhaling any harmful particulates. Always consult the MSDS for the paints and fluids you are using as some paints like Cadmium Yellow are toxic and should never be sprayed. Keep all chemicals and paints out of reach of children and pets. Regularly check your equipment for any signs of wear and tear, and replace parts as necessary.
Acrylics 101: What are Acrylic Paints?
Acrylic paints are a fascinating medium, offering both versatility and ease of use. As you may already know, acrylic paint is an emulsion of water, acrylic resin, and pigment. This emulsion is stabilized by surfactants, which prevent the separation of its components. The acrylic resin in the paint is made up of minute spheres suspended in water. As the water evaporates, these spheres come closer together, eventually fusing to create a flexible, adhesive paint film. The pigment particles are trapped within this structure, giving the paint its color.
The science behind acrylics is quite intriguing. The acrylic medium is a stable emulsion composed of these tiny acrylic resin spheres suspended in water. When the water evaporates, the resin spheres are drawn closer until they touch and fuse together, forming a honeycomb-like pattern. This structure traps the pigment particles, resulting in a paint film that is not only highly flexible but also has excellent adhesion properties. This unique composition makes acrylics ideal for various applications, including airbrushing.
Mixing Liquitex Medium Viscosity Artist Colors for Airbrushing
When it comes to airbrushing, the viscosity of the paint is crucial. As I’ve mentioned before, over-thinning the paint can lead to several issues, such as insufficient paint film or an unstable emulsion. To avoid these pitfalls, I’ve developed a stock paint formulation specifically for airbrushing. This formulation includes pre-mixed paint of the desired color, Airbrush Fluid Media, Slow-Dri Retarder, and distilled water.
Thinning the stock solution to the final viscosity for airbrushing is an art in itself. I’ve found that a 1:20 solution of Flow Aid and water works better than just water alone. Preparing a more concentrated stock solution allows me the flexibility to thin small quantities for spraying as needed. Remember, always use distilled water for mixing paint and other solutions. The chemicals in tap water can adversely affect both the paint film and pigments.
Airbrush Equipment: Compressors
Oilless, pancake compressors like those you find at local hardware stores are simple to use and portable, but — in my experience — tend not to hold up under the frequent cycling required to fill the reservior – they are really meant for nail guns and the like. The air output is usually adequate to run a small airbrush, but they are typically quite loud. Though more expensive, a piston type compressor IMHO is the better choice, but care must be taken to add filters in the airline (and keep them maintained and/or changed) as these types of compressors can aerosolize small amounts of oil which will contaminate your lines and paint. Regardless of which type of compressor you choose, you will likely need to install an adjustable pressure regulator allowing you to decrease the shop pressure to that which is needed for your airbrush (consult your airbrush manual).
Maximizing Spraying Time
Unfortunately, Acrylic paint is more finicky to work with than solvent based paint. The paint film sticks to the needle and builds up clogging the Airbrush. But there are some tricks that you can use to extend the working time: lubricating the needle with petrolatum or silicone oil, painting will small amounts of paint and flushing with alcohol or water frequently, and consider preparing multiple stock solutions of different colors in advance. This way, you can easily switch between colors after flushing the airbrush. Also, make sure to keep all your equipment in top condition to avoid any interruptions.
Airbrushing Interference/Iridescent Colors
Lastly, Interference and iridescent colors offer a unique visual experience. These colors achieve their mesmerizing effects by mixing finely ground mica with the pigment. However, spraying these types of pigments comes with its own set of challenges. The mica particles WILL clog an airbrush if a smaller orifice is used. Therefore, you can either use a larger orifice or a spray gun. Either way you will need somewhere between 0.8 to 1.2 mm orifice for reliable spraying. I found that using a small spray gun like my Iwata LPH80 and masking to prevent overspray gives the most reliable result.