Spray Guns in the Studio—Numerous Art Applications
A spray gun can be simply described as a large airbrush that can be used in the artist’s studio to apply a variety of paints, varnishes, gesso, ceramic glaze and metal patinas for sculpture. It also can be used for painting murals, automotive and metal surfaces, signs and large canvases. Once you’ve used a spray gun, its many possibilities will soon become obvious.
You can find a variety of spray guns in your local art supply store, and two types are usually carried—the conventional spray gun and the HVLP (High Volume Low Pressure) spray gun. The HVLP spray gun is fairly new to the market and was developed to allow the user to spray volumes of paint with a minimum amount of overspray.
The artist should be familiar with two terms when purchasing a spray gun: psi (pounds per square inch), which refers to the amount of air pressure that is delivered to the gun by the air source (normally an air compressor); and cfm (cubic feet per minute), which is the volume of air that is consumed by the spray gun. Both of these settings are regulated by the air source. The psi is adjusted with the air regulator, whereas the volume of cfm is determined by the size of the air compressor. Higher horse power equals higher cfm.
Depending on the gun used, a compressor with high horse power will propel either a large or a small spray gun. However, a small compressor is designed to propel only an airbrush.
The conventional spray gun delivers paint at a high air pressure. This results in more overspray (the amount of medium that drifts into the environment), which can be a health and environmental hazard, and can inadvertently coat objects in the studio, so it’s best to keep the psi as low as possible. The HVLP spray gun is the opposite of a conventional spray gun in that it doesn’t work at a high psi. Ten psi is its maximum, but it consumes a much higher cfm than the conventional gun. A minimum 2-1/2 HP compressor is required to develop the cfm required to propel an HVLP spray gun. Because you are spraying at such a low psi, the HVLP transfers 80% of the paint onto the surface. This saves on the amount of paint used and also reduces the overspray. The HVLP produces a silky smooth, highly atomized finish that is perfectly suited for custom automotive painting or working on metal surfaces, e.g., sculpture.
Spray guns are available in different sizes from mini—such as the Iwata RG-2—to large production guns—such as the Century Series W-200/LPH-200 Siphon-Feed Spray Gun. Like airbrushes, styles include side feed, bottom feed and gravity feed. All spray guns can be attached to external pressure pots for very large projects.
Maintaining the spray gun is basically identical to that of the airbrush—flush between color changes and clean thoroughly before storing.