How to Set Up an HVLP Paint Gun

HVLP spray guns, also known as gravity-fed spray guns, take practice to learn to set up properly, but once you learn how to do it, the procedure becomes second nature. HVLP spray guns have either three or four knobs which must be adjusted prior to spray painting a surface. Two knobs are used to control the pattern of spray, while two more control the amount of air allowed into the spray gun's air chamber.

Instructions

1

Hold the spray gun in your dominant hand and plug the air line from the compressor into the fitting located at the base of the gun. Do not fill the spray gun with paint until the knobs are properly set.

2

Adjust the knob at the base of the handle of the spray gun until its gauge reads between 32 and 40 psi, which prevents too much air from entering the spray gun. Pull the trigger to determine the air output. When holding the spray gun, the knob located on the handle halfway between your thumb and forefinger is the air pressure regulator knob. It can only be rotated in 1/4- to 1/2-turn increments. Set it to its halfway position for paint or clear coat, set slightly higher to spray primers.

3

Adjust the knob just above the air pressure regulator knob. This is a locking knob which controls how much paint is allowed into the air chamber when the trigger is pulled. Until you can adjust it with paint inside, set it to its halfway position. Fine tuning is required after you first apply paint, because of the differences in ambient air temperature, thickness of sprayed material and the speed with which you want to work.

4

Adjust the final knob on the HVLP spray gun which is located on the side of the handle. This knob controls the spray pattern of the gun. If your are painting a large object, like an entire vehicle, turn the knob counterclockwise to its fully open position. For trim work or painting smaller areas, use a smaller, tighter spray pattern to over spray.

5

Fill the spray gun's paint cup and perform a test pass on a large sheet of paper or masking paper on the vehicle. If the paint sputters out in large droplets, adjust the air pressure regulator knob to increase the amount of air. Make another pass to ensure that the correct amount of spray is attained, which should be similar to that of an aerosol spray paint can.