Air Compressors

A helpful tool that can run other power tools and make them more effective is the Air Compressor.  You have likely seem them in auto repair shops and garages where they use pressured air to run impact wrenches and inflate tires.  They are also common on construction sites, woodworking shops, where they run pneumatic (pressurized air) tools of all kinds, including wrenches, nailers, drills, paint sprayers, and dust collection for saws.  On smaller scale, they are also used in dentist offices to run the tooth drills.  

An air compressor is a machine that uses a power source to increase the pressure of air (pressurize), then uses a tank or container to store the pressurized air while using valves and hoses to release the pressurized air into a tool or other attachments.   

If you are already familiar with air compressors, here's a table of my top recommend ones.

Types of Air Compressors

Air compressors can be categorized in different ways and here are the main types for home renovation, woodworking, contractor, and construction use:

• Pressure Method Type - Either Positive Displacement or Dynamic.  
  • Positive Displacement compressors pressurize the air by reducing the volume of the air in a confined container ('displacing air').
  • Dynamic compressors pressurize the air by providing force to the air using some type of blade to move the air ('restricting air').
• Air Pump Motor Type - For consumer and contractor grade compressors, the design types are Single-Stage and Twin-Stage as well as Oil-Lubricated and Oil-Free.
  • Single-Stage compressors use one or more pump pistons to pressurize the air at the same output pressure.
  • Twin-Stage compressors use at least two pistons where the first one pressurizes air at a starting pressure into a second piston that further pressurizes the air.
  • Oil-Lubricated compressors use oil to lubricate the pump motor pistons and other pump moving parts and their pumps are usually larger.
  • Oil-Free compressors have pistons and pump motor parts with special coatings that act as a lubricant and their pumps are usually smaller.
• Portability Level - can be Portable or Stationary.
  • Portable compressors are designed to be carried or wheeled around a home or jobsite and usually have a smaller footprint.
  • Stationary compressors are designed to stay in one place, connect directly to a home, auto garage or jobsite power source, and usually have a larger footprint as well having more powerful pump motors.

Features to Look for in an Air Compressor:  

• Power Source - Either electric or gas-powered, with a majority of the ones sold in hardware and home improvement stores being electric.  Note if either 110V or 220V.
• Pressurized Air Flow - measured in Standard Cubic Feet per Minute (SCFM), starting at 1 SCFM up to 20 SCFM for most tools.
• Pressure Output – measured in Pounds per Square Inch (PSI), starting at 10 PSI up to 120 PSI for most tools, with a common lighter-duty output of 90 PSI.
• Tank Capacity – measured in Gallons and usually come in a range of 1 gallon to 80 gallons for most home, contractor, and construction uses.
• Power Level – measured in Horsepower (HP), with air compressors for DIYers and contractors usually starting from 1.5 HP and going up to between 15-20HP.  
• Pressure Regulator - a pressure regulator will help control the air flow from the compressor, show precisely the pressure level, and adjust the pressure level according to your needs.
• Air Hose - usually comes with the compressor, but if it doesn't, you'll need to get one.
• Roll Cage - protects the compressor motor from being damaged.
• Universal Connectors - makes it easier to switch out different pneumatic tools.
• Thermal Overload Switch - this switch automatically shuts down the compressor motor if it overheats
• Dryer or Air Line Filter - adding a dryer agent to the air compressor will help protect your equipment from the moisture contained in compressed air that can damage the pneumatic parts over time.  An alternative to a dryer is an air line filter, which traps water, oil and dirt as you're using the compressor.
• ASME Certification - a certification label stating that the compressor meets the standards of the American Society of Mechanical Engineers and is an indicator of higher-quality craftsmanship

How to Choose the right Air Compressor based on your Tools:  

All pneumatic tools will have an SCFM rating, plus a PSI level.

If you plan to use one air-powered tool with the compressor, find the tool's SCFM rating and multiply the rating by 1.5 to get the minimum compressor SCFM performance level required. The reason for the additional SCFM level is that a compressor's SCFM will decrease slightly when in use.  Choosing a compressor with a SCFM rating higher than your pneumatic tool requirement will ensures that the compressor will be able to continuously provide the tool's minimum air flow level.

If you plan to use with more than one tool type, pick the air tool with the highest SCFM level and multiply that highest rating by 1.5 to get the minimum compressor SCFM performance level required.

If you plan or require to operate multiple pneumatic tools at the same time and you plan to buy a compressor that can do so, add up the SCFM requirements for each tool that you'll use simultaneously and multiply by 1.5 to obtain the required compressor SCFM performance level.

How to Use an Air Compressor

Using an air compressor typically requires starting up the compressor motor, pressurizing the air, filling the air storage tank, regulating the airflow through the hose, and connecting the tool or attachment to the hose, and using that tool or attachment.

For power tools and attachments that can run off compressed air from a tank, the compressor motor will run intermittently to refill the tank.  For power tools and attachments that require continuous air pressure, the compressor motor will run almost continuously until the tool trigger is released or until the motor reaches a temperature threshold that will shut it off for a cool down period.

Air Compressor Safety

A compressor's pressure can be dangerous, which is why understanding how to safely use one is important. Please be aware of the following precautions to ensure safe usage:

• Use a gas-powered compressor in an outdoor setting or well-ventilated area and avoid using near combustible or flammable materials, liquids, and vapors, 
• Use an electric-powered compressor in a dry area, ensure it is plug into the correct voltage socket, and avoid using a generator for power due to it's inconsistent power output.
• Always check your surroundings before turning on your compressor. 
• Never point the compressor hose towards any part of the body, clothing, or skin, and always turn off and unplug the compressor before looking into the hose.
• Don’t block the air inlet grille or obstruct the airflow of the compressor while using it.
• Safety goggles, earplugs, and gloves are recommended

Below you can find the reviews and posts on using air compressors for specific applications.

Posts and How-To Articles: