Make sure your High volume Low pressure (HvLp) spray gun has an airflow regulator. psi ratings vary from paint to paint, and the technical data sheet (tDS) will give you all the specification. For example, we shot our nason at 10 psi, Du pont recommends 8-10 psi. Most guns have three adjustment controls. the fan control is usually located on the side of the gun; it controls the air distributed around the fluid nozzle. it also atomizes the paint and ultimately controls the spray pattern. the fluid control located at the back of the gun controls the amount of fluid being dispersed by the gun. the air micrometer adjusts the air volume and pressure that is delivered to the air cap.