Airless paint sprayers are a highly refined method of applying large amounts of paint to a wall or other surface quickly and with a better finished look than possible with a brush or other tool. The name "airless paint sprayer" is a misnomer, as each method uses pressurized air to blow the paint across a nozzle or orifice and make it into a vapor. Instead, the term "airless" means the sprayers do not need a separate connection to an air compressor or reservoir.
High-Pressure Airless Sprayers
High-pressure sprayers rely on an extremely high-pressure feed of paint to the nozzle, which effectively vaporizes the paint and directs it to the surface you wish to paint to apply it as a spray. High-pressure sprayers can be dangerous, as the vaporized paint and high-pressure spray can cause skin or eye damage if used improperly. These high-pressure airless sprayers have begun to fall out of favor and have begun to give way to other types of airless sprayers.
High-Velocity, Low-Pressure Sprayers
High-velocity, low-pressure (HVLP) sprayers use an extremely fast-moving stream of paint at a low pressure, allowing you to use less-expensive compressors and nozzles. The paint vaporizes -- not due to the back pressure in the system but via the speed at which the sprayer forces through the nozzle or orifice. Often used on automotive paint applications, this type of sprayer produces a fine finish coat.
External Feed Sprayers
Some airless sprayers use an external feed. The paint travels up through the sprayer via a jug or reservoir and siphon tube that attach to the airless sprayer. An external feed sprayer is the simplest type of airless sprayer feed option and one of the least prone to problems.
Internal Feed Sprayers
Some airless sprayers feed the paint directly through the gun and hold the paint in a reservoir rather than in a jug or other external feed mechanism. You must keep these sprayers quite clean for it to function properly.
