Back to Paint Spray Guns
Q: What are the most commonly used spray guns? A: Here are the 5 most popular spray guns with a short explanation on each: Conventional Air Atomizing
These used to be the most popular for applying high quality paint finishes. Because they are notorious for yielding lower transfer efficiencies than HVLP, many states have passed air pollution regulations that outlaw them or discourage their use. HVLP
Most novices to the paint industry will be surprised to learn that HVLP guns come in a variety of designs concepts. Some are based on turbine technology, some on ventur, and others on inductor technology. Regardless, the regulatory definition of HVLP mandates that the atomizing pressure must not exceed 10 psig. Consequently, transfer efficiency (or transfer rate) usually improves in comparison to conventional air atomizing guns. High quality finishes are more difficult to achieve, but with proper painter training even automotive finishes are possible. Airless Spray Guns
Use very high fluid (coating) pressures (1,000 – 3,000 psig) to achieve atomization. These guns are used for high volume coating flow rates rather than for high quality finishes. Airless spray guns are used to paint buildings, houses, ships, bridges, storage tanks, and more. Because it is generally difficult to control film thickness to 1.0-1.5 mils (as is common for industrial finishes), airless guns are often banned under air pollution regulations for industrial applications. Air-Assisted Airless Spray Guns
These are a compromise between conventional and airless guns. Fluid pressures are only 250-1,000 psig, but a small quantity of compressed air is used to assist in atomizing the coating. Some modern technologies produce good results with atomizing air that does not exceed 1.0 psig. Strictly speaking, these models qualify as HVLP spray guns. Air-assisted airless spray guns (paint sprayers) are rarely used for automotive high quality finishes, but they can produce very acceptable finishes for many industrial applications. Unfortunately, due to a regrettable misunderstanding of this technology, the EPA does not approve of the use of Air-Assisted Airless paint sprayers in several of its regulations. Electrostatic Spray Guns
These guns apply a voltage to paint particles that are atomized by the gun. When the part being painted is electrically grounded, the charged paint particles are attracted to the part, much like magnets with opposite poles attract each other. Due to this principle, transfer efficiency can improve dramatically. Electrostatic paint sprayers do have some limitations and cannot be used effectively in all situations. Finally, the method of coating atomization can be conventional, HVLP, Airless or Air-Assisted Airless. You select the technology based on the type of part being painted. 
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