The amount of air that an air compressor can disperse is calculated by measuring its cubic feet of outflow per minute (CFM).
An air compressor rating of cubic feet, simply means that is the number in cubic feet that will disperse from that air compressor in one minute. (6 cubic feet=6 feet of air in one minute)
This is not to be confused with PSI, which is the amount of forceful pressure the air exerts when released.
Different tools require variances of cubic feet per minute, such as nailing and spray painting.
Spray painting would need an increase in CFM, whereas a nail gun would require a decrease.
If you use an air compressor for multiple tools; chances are, your air compressor has a higher CFM than required to operate the tools efficiently. This will help in prolonging the lifespan of the compressor.
If you have a compressor that doesn’t meet your requirements, there are a couple of different techniques to increase the CFM on an existing air compressor, although not always recommended by manufacturers.
Increasing The CFM
If you are familiar with air compressors, then you know the tank is where the pressurized air remains until used. When the air is released at a certain rate, we refer to this as the CFM.
In order to increase the cubic feet per minute, you need to understand that the compressor cannot function past its capabilities.
Ultimately, if we can allow the tank to build less pressure, then the outflow of air per minute (CFM) will increase.
In order for the tank to build less pressure, the regulator will need to be dialed down. Turn it down to the lowest point of where it can operate.
Turning the regulator down gradually will provide the highest level of CFM over an extended period, allowing the air compressor to function for longer periods while giving the tank the ability and time to fill at the same duration it is being used. Decreasing the pressure allows for greater output and is a safe method of increasing the CFM.
There is another method of increasing the CFM, and this is by connecting two air compressors. This method will allow for a higher level than what the compressor’s ability to function is. This method serves a purpose if you have an extra functioning air compressor not being used.
So, let’s say, you have a compressor with a CFM of 4, and another with a CFM of 6. You can simply connect the two for a CFM equaling 10.
Since you will run both air compressors at the same time, you will need double the energy for them to operate. Connecting them to different circuits is the best option to avoid tripping the electrical fuse.
Connecting The Two Air Compressors
- Two air compressors
- Three air hoses
Steps To Connect
- Take two air compressors and insert an air hose into the couplers on each unit
- Connect both of the air hoses with a T-fastener
- You will then need to fit a third hose to the T-fastener
- Fit your tool to the end of that hose
There are benefits of using this method to increase the CFM on an air compressor, as it will enable the use of a variety of tools to be used.
If you don’t have the luxury of a second air compressor to connect to your existing one, the only other option would be to purchase a larger unit. This method, however, does not come without disadvantages.
Disadvantages Of Connecting Two Air Compressors
- The tanks will need more time to fill
- The unit might overheat
- More maintenance to keep both units running
- Air tool may not be as efficient
Although this method is quite simple, providing you have access to a second unit, there are a couple of factors to keep in mind.
- You will need to install check valves in each of the hoses that are connected to the compressors, for the prevention of air escaping from the unloader valve of the second air compressor
- You may need to install pressure switches to prevent improper wearing of the units
Suggested Air Compressor with a High CFM
Ingersoll Rand Air Compressor
- The ability for multiple users
- 10.3 CFM @ 90 PSI
- Two-4gallon tanks
- Quick connection couplers
- 3 HP
If you’re interested in working with pneumatic tools, you are going to need an air compressor. Both of the above methods will work for increasing CFM, but if you haven’t already purchased an air compressor, it would be best to take the time and research accordingly.
It’s always in the best interest to purchase one with a higher CFM than you may need at the moment; that way later on, if you decide you want to spray paint your house, you will have an air compressor with the proper CFM to handle such a task.