CFM: Cubic feet per minute. A unit measuring the volume of air pumped from a compressor.
Double Action: A trigger design enabling the user to control the proportion of paint to air, allowing the highest degree of control over spray volume and density. (See Single Action.)
External Mix: A simple type of spray gun in which the air and paint are mixed outside the body of the airbrush. (See Internal Mix.)
Gravity Feed: A type of airbrush in which the paint is held in a cup or reservoir attached either to the top or side, and fed by the pull of gravity. More suitable for detail work than a siphon feed model, but only holds small amounts of paint.
Hose: Connects the airbrush to its source of air.
Internal Mix: A type of airbrush in which the paint and air are mixed within the airbrush, resulting in an extremely fine atomization of paint. (See External Mix.)
Mask: Any material which can be used as a stencil to keep areas free of paint while airbrushing, including acetate, mylar (polyester film), frisket film, tape and card stock.
Moisture Separator/Regulator: A mechanism which attaches between the compressor and the airbrush, removing moisture from the air that can condense in the airbrush hose and inhibit paint flow. It performs the functions of a regulator and a moisture trap in a single unit. Its use is mandatory in silent tank compressors and it is often built right into the compressor.
Moisture Trap: A device used with the airbrush hose, which draws excess moisture out of the airflow.
Needle: Long, tapered rod, which holds the paint as it travels on its way out of the airbrush.
Nozzle: Tapered to fit the tip of the needle, it is the point at which the paint spray leaves the airbrush. Also called the tip.
PSI: Pounds per square inch. A unit measuring air pressure.
Preset Handle: Adjusts to stop the trigger as it is pulled back, setting a constant paint flow.
Regulator: A device attached to the compressor and fitted with a gauge which adjusts air pressure.
Remote Mount: A device which mounts a regulator at a workstation rather than onto the compressor, making the adjustment of the air pressure more convenient.
Single Action: A simple type of airbrush design in which the trigger releases the air and paint spray, but does not allow any variance in flow. (See Double Action.)
Siphon Feed: A type of airbrush in which the paint reservoir is held in a cup or bottle attached to its underside and is fed into the airbrush by a siphon.
How the Airbrush Works
An airbrush is a sophisticated spray gun. Liquid paint is mixed with a stream of pressurized air, supplied by a hose connected to a compressor, and sprayed out through a fine nozzle. A trigger (finger lever) that opens and closes the nozzle controls the paint spray. There are two types of triggers: single action and double action.
In a single action airbrush, the spray is controlled by pressing the trigger. No regulation of the paint flow, other than shutting it off, is possible while painting. Therefore, any adjustments to the nozzle for selecting spray pattern need to be done before painting begins. Some single action airbrushes are equipped with an adjustable handle that can open or close the nozzle to adjust the paint spray with more ease.
For achieving the greatest control of paint spray, a double action airbrush is best. In this type of airbrush, the trigger is depressed, opening the air valve and allowing the air to flow from the hose to the airbrush, just as it does in a single action airbrush. What differentiates the double action airbrush is that the trigger can then be pulled back (with the fingertip), drawing the needle back and opening the nozzle tip, allowing paint, mixed with air, to escape in a spray pattern. The farther the needle is drawn back, the wider the nozzle opening and the larger the spray volume. When the trigger is released, the needle returns to its original position, closing the nozzle opening and halting the paint flow.
Most airbrushes can be converted into three sizes by changing the needle, nozzle or nozzle cap. The smaller the nozzle diameter, the finer the spray line. The larger the nozzle, the broader the spray line. For spraying heavier paints, such as acrylics, fabric paints or enamels, larger size needles and nozzles are generally required.