Now, take the gun and point it at a fresh spot on the test panel. Pull the trigger back all the way, and at the same time, turn the upper fan adjustment counterclockwise. As you do this, you'll notice that the pattern on the panel will get the long, fan-like shape that you'll need for painting. What you're looking to achieve as a starting point is about an 8- to 11-inch-tall pattern (again, this is just a basic starting point, and can be adjusted as you see fit). The next thing you'll want to pay attention to during these test trigger pulls is the amount of material being transferred to the surface. You're trying to achieve a full, wet, even pattern. If you're getting a dry, spotty, starved pattern, you'll want to open up the fluid adjustment (try a full turn at a time) until you reach that point. But remember, the more you open the fluid adjustment, the more paint you're going to be spraying and the more you're going to have to worry about runs and sags.
Spray gun technique and its relationship to a quality finish are often misunderstood. It's important to know that there are three (actually four, but who's counting) important facets of proper technique that are essential for success. Learning and following these techniques is of the utmost importance for those who wish to apply finishes that will rival those of professionals. The facets are: angle, distance, speed, and overlap. Once you've got the hang of these, you got the painting thing down pat!
Gun Angle The first facet of spray technique is the spray gun angle. It's important that the spray gun be kept at a 90-degree angle to the surface being sprayed. You always want to move the gun back and forth over the area being sprayed in a perfectly perpendicular manner. This will mean that for larger areas you'll have to rotate your wrist at the beginning and end of each stroke to keep the gun at a 90-degree angle from the work.
In other words, let's say you're starting on a door panel. You'll want to position yourself at the door so that each end of the panel is about an equal distance from the center of your stroke. Positioning the spray gun so that your first pass begins at the left edge of the panel (assuming that you're right handed) will have your wrist automatically cocked to the right. As you slowly move the spray gun toward the right you'll notice that in order to keep the gun perpendicular to the surface, your wrist will automatically begin to straighten out. By the time you're midway through your first pass, your wrist should be about in line with your arm. As you move the gun farther to the right, your wrist will begin to rotate to the left. Pivoting your gun hand at the wrist in this manner will take a bit of concentration in the beginning, but it will become second nature by the time you complete your first paintjob.
Gun Distance The basic gun-to-surface distance recommendation is about 6 to 8 inches from the surface for fast-drying products like lacquers (for those lucky enough to live in less restrictive communities), and 8 to 10 inches from the surface for slower-drying materials like enamels (and emissions compliant materials). Holding the gun too close to the surface will restrict the separation of the atomized paint particles, resulting in big, nasty runs, sags, or, as I've been known to create, "curtains." On the other hand, holding the gun too far from the surface will cause the paint to over-atomize and to go on dry, rough, and with poor hiding characteristics.
Gun Speed And Overlap Gun travel speed will vary greatly from one painter to another. There are lots of variables that come into play at this point that have a direct effect on just how fast the gun will have to move to deposit the correct amount of material on the surface for proper coverage and flow. The size of the fan pattern, the amount of material exiting the gun, the material viscosity, and the air pressure at which it's being sprayed all has to be considered.