Two distinct knobs control the fluid flow and pattern of a spray gun. The fluid control knob is typically located at the top rear end of the gun near the liquid tubing nozzle. When the knob is tightened, it pushes the trigger forward for maximum fluid flow and ideal atomization. The pattern control knob may be located on the side of the gun or near the fluid control knob. Adjustments to the pattern control knob change the orientation and size of the spray pattern. Many guns feature various increments of horizontal and vertical spray patterns.
When the trigger is pulled, the valve opens to begin the spray cycle. Spray gun performance is based on pressure levels, the fluid control knob setting, and distance from the surface. To achieve a smooth coat, the spraying motion should begin before pulling the trigger. Automatic air spray guns, used with dispensing robots, are triggered by programmable switches.