How to Adjust a Paint Gun
A paint gun delivers a much more controlled and even finish than brushing or rolling. It takes a little practice to get comfortable moving and adjusting the gun.
Start by lightly pressing the trigger to spray air. Set the nozzle about 6 inches above and perpendicular to your work.
Choosing the Right Gun
There are many different types of paint guns – each with their own specific technology and application. Figuring out what kind of gun will best suit your needs can take some time and research.
The most important part of the spray gun is the nozzle – this determines the shape of the paint jet. The nozzle should be adjusted for the particular paint being used. This is done by changing the air cap.
Another thing to consider is the type of work you will be doing with the gun. There is no point in spending a lot of money on a paint gun that will do something that you will only use a few times a year. The quality of the work you do is far more important than the type of paint gun you use. For example, an automotive paint gun will have a different design than a gravity feed home sprayer. This is due to the fact that they are designed to be used for longer periods of time.
Adjusting the Nozzle
The nozzle on your paint gun needs to be properly adjusted. First, you need to have the fan size just right for your project. This adjustment can be done by depressing the trigger and turning the nozzle at the back of the gun to get the desired fan shape/width.
Then you need to adjust the fluid control knob at the back of the gun for the correct amount of fluid to be sprayed at the same time as the air. You want to be able to lay on a decent coating of finish without runs at the normal gun sweep speed.
Different nozzle setups are recommended for different materials. For example, there are special nozzles for primers and surfacers, and others for basecoats and clearcoats. Many painters use one gun with multiple nozzle sizes, but this takes extra work to change from material to material. It is best to follow the manufacturer’s recommendations for specific products and nozzle sizes for optimal results.
Adjusting the Flow
Getting the proper air pressure is crucial. Most paints will tell you what the optimal pressure is for them, but you need to check your gun’s air pressure gauge and follow the manufacturer’s recommendation.
If your gun is leaking or spraying unevenly, it’s likely the fan width needs to be adjusted. If the fan is wider, this will reduce the amount of paint that’s ejected from the gun, which in turn will thicken the coat.
To reduce the flow, you’ll need to screw the control feed in (a knob on the back of the gun). Some paints work better with thin coats while others can be applied heavier. Increasing the amount of material you apply is easy by un-screwing the feed control and adjusting the pressure on your gun. Counting turns when making adjustments can help you learn how many full twists are needed to change the settings. You can also make incremental adjustments by a few pounds to get an idea of the difference each makes.
Adjusting the Pressure
Air pressure, or PSI (pounds per square inch of air pressure), varies by gun and paint. Look at your gun manufacturer and paint can instructions for the recommended range. If you don’t have a gun with an internal air pressure gauge set the compressor and hose to that range, then use an air regulator at the end of your air hose before it connects to your gun, and a filter in between the gun and the regulator.
Start with a low pressure setting and trigger the gun quickly–if you see a full spray pattern, then you’re ready to start painting. If the pattern is not fully filled, increase the pressure setting and test again. Repeat this process until you get the desired results. Be sure to strain your paint before pouring it into the gun–boogers (clumps of dried paint, dirt and whatever else) can clog a gun quickly. This can lead to poor atomization and an uneven finish.