3-12. Airless Spray Systems.
a. In an airless spray system (Figure 3-43), the spray is created by forcing paint through a
restricted orifice at very high pressure. Paint atomization occurs without the use of air jets, thus the
name airless spray. Liquid pressures from 1,900 to 2,600 pounds per square inch are developed in
special air-operated, high-pressure pumps and delivered to the gun through a single hose line.
b. The system provides a very rapid means of covering large surfaces with a wide-angle spray
without producing overspray mist or rebound. The single, small-diameter hose makes gun handling
easy. The spray produced has a full wet pattern for quick film buildup. However, the system requires
extra care when lapping and stroking to avoid excessive coverage that would result in runs, sags, or
Figure 3-43. Airless spray system
An airless unit with a self-contained heater (Figure 3-44, page 3-36) is also available. The advantage of
the hot sprayer is that it uses heat rather than thinner as the viscosity-reducing agent. As a result, the hot
sprayer is very compatible with VOC regulations.