When choosing an air compressor to use with your plasma cutter you need to consider the compressor’s CFM rating (cubic feet per minute) and the amount of CFM your plasma cutter consumes. Any compressor can work for small short cuts, but in order to keep your long cuts uninterrupted by a lack of air pressure you need to have a compressor big enough to keep up with your machine’s air consumption.
What Size Compressor Should I Get?
The general rule for buying a compressor is the bigger the better. Manufactures recommend you buy a compressor that is rated for about 1.5 times the CFM (cubic feet per minute) of your plasma cutter. For example, the Hypertherm Powermax30 XP requires 4 CFM at 80 PSI. Ideally, you would want a compressor rated around 6 CFM to use your machine without interruption during heavy usage.
With all of this said, you can get away with using a smaller compressor as long as you are not making super long cuts with your plasma cutter (longer than a minute). A majority of users are only making small to medium sized cuts, so they can use a compressor that is under the recommended manufacture sizing. A small 30 gallon compressor rated at 5 CFM will work without any problems for most users.
Keep in mind, if you use a smaller compressor and start making longer cuts, your compressor will not be able to keep up. This will cause your machine to throw a low pressure warning light and stop working temporarily while the compressor takes time to build more air.
Campbell Hausfeld 30 Gallon Air Compressor (5.3 CFM)
This is a compressor that will work for a large majority of plasma cutter users. At 5.3CFM at 90 PSI it will hold up just fine in an average weekend work environment. This will get you by with little to no interruptions and it won’t cost you an arm and a leg. If you go any smaller than this, you’ll be wishing you got something bigger.
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What PSI Do Plasma Cutters Need?
Plasma cutters operate on a wide range of different PSI settings and you must refer to your machines manual to find the correct setting for your machine. In general, larger machines require a higher PSI and smaller machines require a lower PSI. For example take a look at the different machines below offered by Hypertherm:
- Hypertherm Powermax30 XP (30 amp): Runs at 80 PSI using 4 CFM.
- Hypertherm Powermax45 XP (45 amp): Runs at 90 PSI using 6.7 CFM.
- Hyperterm Powermax65 (65 amp): Runs at 85 PSI using 6.7 CFM.
Regulating Air Pressure
Most plasma cutters have a built in air regulator in the machine that will choke the air down to the correct pressure needed. If your machine does not have this (check your manual), you can purchase an external air regulator to mount on your plasma cutter or your compressor. This will allow you to adjust the PSI of your air supply line.
Bostitch Adjustable Air Regulator (0-140 psi)
This air regulator can be attached to your air compressor or plasma cutter. It will allow you to restrict the airflow to the correct PSI for the tool you’re using. It has standard 1/4 inch connections and is easy to setup. Make sure you look for the airflow direction labeled on the unit when installing.
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Air Filters and Air Dryers
Compressors naturally create air that contains moisture, oil and particulates, so it’s best to filter out these contaminates using a filter before it reaches your plasma cutter. Dirty air can cause increased wear on consumables and degraded cut quality. There are a variety different types of air filters and air dryers, but most fabricators choose an all in one cartridge filter that is quick and easy to change. For more information check out our article about air dryers for plasma cutters.
Motor Guard M-30 NPT Submicronic Compressed Air Filter
The Motor Guard is a common inexpensive filter that is used and recommended by many. It’s well known on many forums as the “go to” filter for plasma cutters as it’s simple to install and easy to maintain. It houses one single replacement cartridge that traps moisture, oil and particulates from going into your air supply line. With Motor Guard being so popular you can be confident that replacement filters will be available many years from now.
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Running A Plasma Cutter Without An Air Compressor
If you don’t have an air compressor or need a more mobile solution, compressed air tanks are a great alternative. They will provide your plasma cutter with very clean air without the need of a compressor or filter. A tank can be rented and filled from your local welding shop, but refilling the tank does cost money.
Alternatively, you can also purchase a plasma cutter with a built in compressor. These machines only require a power source to operate because they have a compressor built into the machine itself. For more information visit our write up on the best plasma cutters with built in air compressors.