How to Use an Air Compressor

A few months ago, we tested to find the best framing nailers. We've also compared the best air compressors. We had a lot of fun, but every aero mod would be useless if it weren't for the unsung hero of that shootout: the air compressor. However, not everyone knows how to use an air compressor properly. In this entry in our Train an Apprentice series, we cover the basics.

Framing nailers aren't the only tools that require pneumatic (air) power to function. Instead of electricity, many tools in the pro and DIY arsenal use compressed air. Compressed air plays an important role in construction, machinery and paint applications. In short – don't skimp on this tool!

If you're just learning how to use an air compressor, don't stress. It's effortless to pick up, and once you've gone through the process a few times, it can seem like second nature.

Editor's note: Be sure to check out our recommendations for the best portable air compressors for your home garage

How to Use an Air Compressor – Initial Setup

Let's start by checking the oil. Most small air compressors these days don't need oil to run, but larger ones might. Regardless of size, before starting your air compressor, check the manual to make sure your compressor uses oil, and where it goes.

Chances are, if your compressor does need oil to run, you'll find the dipstick near the bottom of one of the compressor ends. Pull it out and check the oil level like you would check your car's oil. If it's getting lower, add more.

In some cases, such as our 80 gallon NorthStar compressor, the manufacturer provides an easy-to-read window in the tank. Compressor oil can be found at most hardware stores, auto parts stores, and home improvement stores.

Fuel is required to use a gas powered air compressor

When you're using a gas-powered air compressor, try something like ethanol-free gasoline or TruFuel premix. It will help your compressor last longer. If you absolutely must use regular gasoline, add an ethanol-specific fuel stabilizer, such as Stabil.

You may also need a break-in period to run optimally. Check the manual to see which break-in procedure you should use on your new compressor. A good rule of thumb is to open the drain and let the air compressor run for 30 minutes.

When using an electric air compressor, be careful with the cord length

Obviously, an electric air compressor needs power, so plug it in. If you don't have a working outlet near where you plan to work, avoid using extension cords on AC models if possible. The wrong extension cord can cause the compressor to overheat. It's a good idea to connect multiple air hoses together to supply air to your tools.

If you don't know which extension cord will work with your air compressor, check out our extension cord size chart for reference.

Connect the hose to the regulator

Connect the hose to the regulator valve. That's the valve next to the pressure gauge on the compressor. This part should be easy to figure out, but your hose will have a male connector and your compressor will have a female connector.

You'll need to slide the moving part of the coupler in so you can connect the hose end. If there is air in the compressor, when you lock the hose in place, some air will be released and you will feel it push back.

On the other end of the hose you will have the same type of female plug. The tool has a male stem that connects to an adapter on the end of the hose.

Test the safety valve

Pull the safety valve. You should be able to find it near the hose. If you pull it and hear the air hiss, you're in good shape. Push the valve back in place before starting the compressor. If you don't hear air escaping, but can put the valve back in place, you're probably still fine.

Turn on the compressor and fill up the water tank

Turn on the compressor and wait for the tank to fill up. You'll know you're ready to go to work when the needle on the tank pressure gauge stops moving forward and the motor stops.

Figure out how much air pressure your tool needs to run properly. Typically, this information will be printed on the bottom of the tool. If you can't find it on the tool, the manual will certainly provide that information. Each tool has a different PSI rating, so when you change tools you will also need to adjust the hose pressure.

However, PSI is not the only consideration. You'll also want to check the SCFM requirements, or how much airflow the tool needs. Tools like nailers require only quick bursts of air, while tools like air sanders require high levels of sustained airflow.

Adjust the air regulator

The next step requires you to adjust the regulator knob. One way (usually clockwise) will give you more pressure, while the opposite direction will decrease the pressure. It only takes a few seconds for the compressor to stabilize. Don't be afraid to make small adjustments until you get it where you want it.

Every time a power tool is used, the pressure in the tank drops as compressed air travels through the hose to the tool. When the pressure in the tank drops too low, the compressor will restart, refilling the tank.

However, PSI is not the only consideration. You'll also want to check the SCFM requirements, or how much airflow the tool needs. Tools like nailers require only quick bursts of air, while tools like air sanders require high levels of sustained airflow.

Know Your Duty Cycle Rating

Each compressor has a duty cycle rating. This is the operating rate that the motor can handle without causing damage. Some compressors can have a 100% duty cycle, which means you can use it non-stop throughout the day if you want.

Others may have a 50% duty cycle. If you use it for 5 minutes, it needs to rest for 5 minutes. Typically, an air compressor with a duty cycle below 100% will tell you specifically how long it can run (for example, 10 minute intervals).

Maintain Your Air Compressor

You need a break at the end of the day, and your compressor needs to decompress.

Drain the tank

When you're done working, you'll need to open the drain valve at the bottom of the tank to release all the water. This needs to happen after each use, as water and metal don't usually get along for long. Where we are in Central Florida, there is a bit of salt in the air that speeds up the rusting process. Since the rust starts on the inside of the tank, you won't notice it until brown water starts coming out.

Turn off the compressor first. When you open the drain valve, the escaping air will also push out any moisture that has collected around the bottom of the tank. Alternatively, turn the pressure adjustment knob to shut off the air supply to the hose and shut off the compressor. Then, wait for the pressure to leave the compressor. You can pull the relief valve to release the air faster. However, this does not release moisture.

Watch out for air filters

Get in the habit of checking your air filter every time you use it. Too much gunk starts to drain the motor and can cause it to fail. Replace it when you start to see a lot of buildup on it.

check the oil again

When you're done with hose storage, take this opportunity to check the oil again and replace if it gets too low. Once a year, you need a complete oil change. Consult your manual for the best way to solve this problem.

air tank life

Air compressor oil tanks have a limited lifespan. While draining the tank helps lengthen it, it still runs the risk of eventually bursting. Check the data label to see when the air tank should be replaced.

Finally, if you have any tips or tricks on how to use an air compressor, feel free to add them in the comments section below.