A spray gun is a device that is similar to a gun and is used to spray a liquids such as paint under high pressure. Generally, there are two kinds of spray guns, Electric and pneumatic (air powered). Most spray guns are connected to an air compressor and the pressured air sprays liquids to the project you are working on and this gives a very nice smooth surface to it. With spray guns, you will be able to apply paints, varnishes, lacquers, shellac and other finishes to automobiles, furniture, and other appliances. An electric spray gun, has no air compressor and it works with an electric motor which sprays the paint out with a lot of pressure.