Airbrush Air Supplies and Compressors
The essential parts of an airbrush are the body with the needle, the paint (ink or dye) container, and the air supply. The basic action of an airbrush is the atomization of the paint. This means that the material to be sprayed is broken apart to produce a fine mist. For this to happen, a good and reliable air supply is necessary. It is the air pressure, measured in pounds per square inch (psi) that determines the right atomization in an airbrush depending upon the results one needs. When air pressure is insufficient, the airbrush produces a stippling effect, with patterns in varying degrees of solidity. When there is too much pressure, the result is an overspray producing a diffused halo of color around the area being sprayed. The right air supply is also an important consideration in the choice of the needle and the paint. An airbrush with a fine needle requires less air pressure to produce a fine spray. The right match must be found between the viscosity of the paint to be used and the air pressure.
The air source of an airbrush is where the compressed air comes from. This may be an aerosol can, a CO2 tank, an air regulator or a compressor. Some adventurous airbrush artists have been known to use a tire's inner tube as an air supply source.
Choosing the right air source depends on three factors: a) the kind of airbrush being used, b) the airbrush job being undertaken, and c) the volume of airbrushing to done. The advantages and disadvantages of the more common types of air sources are listed below.
Aerosol can: It delivers constant and reliable air pressure. Easy to handle and relatively inexpensive, you can readily find it at the supermarket or hardware store. It's quiet, handy, and is ideal for occasional jobs that don't need much precision. On the other hand, it has very low air pressure and runs out fast.
CO2 tank: It does not require any electricity, and does not produce any moisture which can affect the paint. A silent, portable air source, it is not too expensive, and can even be rented. The down side is that it needs to be refilled and can pose a risk because it is a compressed inert gas.
Compressor: There are different kinds of air compressors most of them with, but some without, holding tanks. All of them have built-in regulators and require electricity for power. A compressor without a holding tank has the advantages of being small, inexpensive and long-lasting. However, it has low, fluctuating pressure causing the air flow to pulsate, gets hot and is noisy.
Some compressors need lubrication, while others don't. The Oil-lube and Oil-less models are both moderately priced, deliver constant air at higher pressures and can shut off automatically. Both are noisy and require regular “bleeding” of moisture. The Oil-lube type has the additional risk of oil entering the air line.
The Silent (or “Pancake”) compressor is compact and delivers constant air and is exactly what its name implies. The disadvantage is its high cost and the need to “bleed” the moisture frequently.