Most HVLP (high-volume, low pressure) spray guns have three basic controls:

1. Fluid adjustment
2. Fan control
3. Air control.

Check the spray gun instructions if you are unsure where each is located because knowing how to properly adjust these controls will help you achieve a high-quality paint job.

Air control

The air control adjusts the air volume and pressure delivered to the spray gun’s air cap. Set this control before putting paint into your gun. Position it to wide open to reduce any restriction and lost pressure. With this control fully open and the trigger pulled, you should have 25 to 30 psi.

Note: Don’t confuse the air cap pressure with air control pressure. Some paint tech sheets may refer to a painting air pressure of eight to ten psi. This refers to the air cap pressure right where the paint comes out. Ignore this. Instead, set your air control wide open to ensure you have 25 to 30 psi when the trigger is pulled, and the air cap pressure will automatically adjust. 

Fluid control

The fluid control regulates how much paint comes out when you pull the trigger of your paint gun. For instance, if it’s fully tightened, no paint will come out.

Start by spraying on a piece of scrap metal or glass. Open the fluid control all the way, allowing the full amount of liquid to pass through the nozzle opening. Next, with the trigger pulled completely open, start screwing the fluid control closed. Stop when you feel a force from the back side of the trigger. This will allow full-fluid volume to come out of your spray gun.

When you actually paint the vehicle, control misting  by gently pulling back on the trigger.

Fan control

The fan control adjusts the amount of air distributed to air passages and air caps, which affects the length and shape of the spray pattern. Using the fan control, you can adjust the pattern from an oval football shape all the way down to a dot.

To adjust the fan control, start by first opening it all the way while practicing on a piece of scrap metal. Then  back it down by one-eighth to one-quarter turn, until you achieve the right paint atomization.

Understanding and correctly setting the controls on your spray gun will help ensure a professional result on your next paint job.

Check your spray pattern

Before you start painting, it is best to make sure your spray gun is spraying properly. Check your spray pattern first by holding your paint gun firmly in place and squeeze the trigger fully while spraying on a piece of masking paper first. You spray gun pattern should look like the first pattern on the left below.

Cleaning

If you spray pattern looks like any of the other patterns shown above besides the first pattern, then you spray gun most likely needs to be cleaned better. The GLM-100 True Blue Paint Gun Cleaner contains strong solvents that will get your paint gun clean in no time. It is best to remove your needle from the paint gun and clean it separately. Next, remove your air cap and the fluid nozzle with the wrench that came with your paint gun. Clean the cap and nozzle until you can see through all the tiny holes in both cap and nozzle. Make sure you have the proper brushes for getting in the small holes. Reassemble your paint gun in the order you took it apart. Test spray once again on a sheet of masking paper. You should now see that first spray pattern. You are now ready to paint.