Plasma cutting is a process that uses the fourth state of matter, an accelerated jet of incredibly hot plasma, to cut through electrically conductive metals. If you are looking into buying a plasma cutter for the first time, you need to make sure you have the secondary tools to support it, depending on the model that would be an air compressor.
In this article, we will discuss different types of compressors units and some of the top choices on the market. We will also examine the basics of plasma cutters, just to make sure you get the exact air compressor that will best suit your needs.
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Budget Air Compressor Under $500
Although some plasma cutters come with a built-in air compressor, most of the small to medium-sized machines don’t have this advantage.
When considering which is the right one for you, it is important to note that you will pay for convenience.
It is usually the most budget-friendly decision to purchase a stand-alone air compressor and use it with a regular plasma cutter. Nevertheless, you will have to forego the added benefit of portability which a complete system offers.
However, the following air compressor by North Star offers the best of both worlds. It is both portable as well as being under $500.
NorthStar Portable Electric Air Compressor
This portable air compressor by North Star boasts a 1.7 Hp electric motor and a 15-gallon vertical air tank. Although it’s small, due to its portability this air compressor makes for a great small job air source.
One of the things that stands out with the North Star is the low voltage start capability. It ensures that using an extension cord won’t trip the fuse or breaker on a startup.
Top Five Air Compressors For Plasma Cutters
These are the top five air compressors for plasma cutting purposes in 2020:
Ingersoll Rand Garage Mate Portable Electric Air Compressor
If you’re in need of a smaller but reliable and heavy-duty air compressor then look no further. The Ingersoll Rand Garage Mate is an essential piece of equipment for any serious needs that require portability.
The Garage Mate has a strong 3 HP engine combined with its a vertical 20-gallon tank. A convenient handle and large wheels make it easy to move this workhorse where you need it to go.
Puma Industries TE-3040V Air Compressor
This handy compressor has a 40-gallon tank which makes it suitable for larger projects. It can deliver 175 PSI, is oil-lubricated, and includes a cooling system that prevents thermal overload when the engine is used for long hours.
The air pump is powered by an induction motor and, as the motor has a low amp draw, it is easy to start in cold weather.
This is a commercial air compressor with simple and easy-to-use features. The downside to this one is that it is quite expensive due to its versatile applications for home use, commercial use, and industrial use (source).
Quincy QT-54 Lubricated Air Compressor
Large and in charge, the Quincy Lubricated Air Compressor is a giant in the business with a 5 horsepower motor and a 60-gallon tank. It has an industrial-duty motor which makes it very reliable.
The capacitor motor-start in the unit has a built-in thermal overload which is an additional benefit that provides excellent performance. The unit’s working PSI also ranges between 145 to 175, which means it is compatible with most plasma cutters.
The main downside to this one is that it is quite expensive.
Powermate Vx PLA4708065 Air Compressor
The Powermate compressor is also on the expensive side in the range of $1000+, but as it operates with a powerful 15 amp motor, it is one of the best. With its steady deliverance of 155 PSI, it is an incredibly durable machine that can also offer up to 14 CFM with an 80-gallon tank.
An impressive machine, the only con to the Powermate Air Compressor is its price tag (source).
Ingersoll Rand 2475N7.5-V Air Compressor
Although you would use the DEWALT compressor for home or hobbyist use, the Ingersoll Rand air compressor is geared towards industrial use and suited to large shops.
It can deliver 24.2 CFM at 90 PSI or 23.1 CFM at 175 PSI. Although it does come at a high price, the Ingersoll is an exceptionally good heavy-duty machine with a very large 80-gallon tank, one or two year warranty, and a large 7.5-hp motor (source).
Air Compressor Sizing For A Plasma Cutter
To run a plasma cutter for any decent period of time, you will want a compressor with at least a 30-gallon tank, but larger is better. Plasma cutters that are in frequent use or cut very thick metals should use a compressor that has a CFM rating of 1.5 to 2 times the plasma system requirement.
The Purpose of a Plasma Cutter
There is hardly a better tool for cutting clean lines through the metal in record time than a plasma cutter. Due to the high speed and precision cuts that a plasma cutter offers, the range of applications is a hundredfold.
Plasma cutters are most often used in fabrication shops, for automotive repair and restoration, industrial construction, and salvage and scrapping operations.
Smaller handheld plasma cutters are even used in small hobbyist shops and by individuals using the abilities of the machine to create intricate metal artwork (source).
The use of plasma to cut metal originated in WWII when it was discovered that excessively heating gas by accelerating its trajectory made it possible to cut clean and precise lines through very thick pieces of metal. This introduced the world to what is called the plasma arc.
What is Plasma
Plasma is the fourth state of matter, next to gases, liquids, and solids. The amount of heat, or energy, applied to molecular structures determines their behavior and therefore their state.
Although plasma is the most common state of matter found in the universe, here on Earth it is scarcely seen due to the high concentration of heat it needs to exist.
In matter, more heat excites molecules to the point that they break free of their bonds that bind them to one another. With minimal heat, the molecules are tightly bound and you get a solid.
With more heat, the molecules escape the rigid bonds but are still loosely bonded, and you get a liquid.
The third state of matter happens when even more heat is applied and the molecules escape the loose bonds and you get gas. If you heat that gas, even more, that brings you to the fourth state — plasma.
Modern Plasma Cutting
Plasma cutters are highly useful tools with a wide range of applications and have recently become a popular garage addition. Although once very expensive, bulky, and dangerous, plasma cutters have now evolved to include compact, portable models that anyone can learn to use.
A plasma cutter on its own is complex enough, and it requires several secondary tools to function optimally. Aside from the main unit itself, a plasma cutter normally needs at least two extra pieces of gear: an air compressor and an air drying/filtering system.
The compressor provides the air it needs to work, and the air dryer or filtering system will ensure the cutter stays dry. This is important because moisture is one of the main reasons why tools stop working prematurely.
Do You Need an Air Compressor to Run a Plasma Cutter?
The short answer is usually yes, although some plasma cutters come with built-in air compressors, and you can use gas cylinders. But any plasma cutter will require sufficient air pressure in order to work.
The amount of air pressure and the size of the compressor will entirely depend on the size of the plasma cutter in question and what you plan on doing with it.
So, how much CFM (cubic feet per minute) do you need to run a plasma cutter? A standard plasma cutter will require approximately 4 to 8 CFM delivered at 90 to 120 PSI, but different units will have different requirements.
The size of the air compressor should directly correlate with the thickness of the metal that needs to be cut.
CFM and Plasma Cutting
Units of different sizes will have different requirements when it comes to air pressure. It will also depend on the thickness of the metal that needs to be cut.
If your plasma cutter runs on insufficient air, the precision and quality of the cuts will be affected or the machine will simply be unable to operate.
It can be useful to determine what size you need before investing. If you use a smaller cutter, you will be able to use a smaller air compressor. Because air compressors can be bulky, most occasional plasma cutter users opt for smaller units in the 30-gallon tank range.
It is also imperative to determine what you will use the cutter for. If you need to maneuver the cutter around a workspace a lot, it is imperative to get a portable one and invest in a longer air hose for the compressor to make maneuverability easier.
Smaller units that are used for steel cutting of approximately 3/8″ in thickness commonly have air requirements at about 4 to 5 SCFM at 90-120 PSI. Puma has a range of affordable air compressors that will be sufficient for most users, whether you’re a hobbyist, DIY-fanatic, or artist.
Many plasma cutters are small and portable, so they are useful tools for contractors and trade workers that can use these cutters in the field, saving significantly on time and cost.
Small and portable plasma cutter usually don’t have an air compressor built into the unit, but will only require a small compressor that can deliver about 3.6 SCFM at 65 PSI.
Medium-sized units will be able to cut steel of approximately 5/8″ to 3/4″ in thickness and will require about 6 SCFM at 90 to 120 PSI.
Medium-sized units are mostly still portable and are useful for longer cuts and thicker material, although they can also be used in conjunction with CNC tables for projects of a relatively small scale.
A medium-sized machine will also be compatible with most of the available torches on the market. The Hypertherm Powermax65, for example, can be utilized with a hand torch of either 15⁰ or 75⁰, or paired with a mini machine torch or full-length machine torch, both 180⁰.
Large units or heavy-duty units are those that are mostly used in the industrial field. They are utilized for 3/4″-1″ steel cutting and will need about 7-8 SCFM at 90-120 PSI. Really heavy-duty units used for cutting steel of 1 – 3/4″ in thickness will require at least 9 SCFM at 85 PSI (source).
The most effective units that fall into this category will not be portable, and the most efficient use would be to use them in conjunction with a CNC table.
These larger units demand more from their air compressors because they often have to make longer cuts and, as such, a smaller air compressor will not be able to keep up (source).
Selecting an Air Compressor
The Pressure Requirements
If you are considering buying an air compressor for your plasma cutter, you should invest in one that can easily deliver more than the system requirements. The reason for this is to ensure sufficient air pressure and a longer life for your machine.
For example, don’t pair a plasma cutter that requires 4 CFM to a compressor that produces 4 SCFM. It’s unlikely that the compressor will be able to keep up with the demand.
You will need to interrupt your work in order to allow the compressor to build up the required air again. This can mean a poor quality job or a longer time-frame to complete your project.
The requirements on your plasma cutter are measured in SCFM. This means Standard Cubic Feet per Minute, which is calibrated to 68ºF, 0% humidity, and at sea level.
If any of these numbers rise, your compressor output will drop. So, depending on your area, your air compressor might lose efficiency and then not be able to deliver the required CFM.
In order to mitigate the efficiency risk of running a plasma cutter with an air compressor that cannot deliver the required amount, it is imperative to add a fudge factor to the listed air requirements on your machine.
The Fudge Factor
A fudge factor is a figure included in a calculation to account for an unquantified but significant phenomenon or to ensure the desired result.
This means that adding a fudge factor to your air compressor equation will help you mitigate the fluctuation in CFM due to atmospheric pressure, humidity, and any lengthy cuts you might make that will place additional strain on the cutter.
So, when considering an air compressor for your specific plasma cutter, it is recommended to add a 50% fudge factor to ensure that your compressor will be able to keep up regardless of environmental or other factors.
For example, if the specifications of your plasma cutter state that you need to provide 4 CFM at 100 PSI, adding a 50% fudge factor of 2 CFM, you should at least have a compressor that’s rated for 6 CFM. This will eliminate any trouble you might face along the way.
The next step in deciding which air compressor is best is to consider what you’ll be using the plasma cutter for.
Hobbyists or those that do the occasional cutting will require a less heavy-duty air compressor than those utilizing the machine for fabrication purposes, regular cutting, long cuts, or cutting very thick pieces of steel.
With all of this said, you can get away with using a smaller compressor as long as you don’t use your plasma cutter for cuts that last longer than a minute at a time.
Should you try to make long cuts with a smaller compressor, you will find that the air pressure in the compressor falls, and you will need to allow it extra time to build up pressure again before continuing use.
Longer cuts will cause your machine to throw a low-pressure light and stop working temporarily while the compressor takes time to build more air, so that is why heavy-duty compressors are recommended for fabrication purposes.
Plasma cutters that are in frequent use or that cut very thick metals should be using a compressor that is 1.5 to 2 times the plasma system requirement to lengthen the lifetime of the compressor motor and produce quality work overall.
Scope of Work
As the majority of users don’t utilize the machines for very long cuts, a small compressor with a 30- to 40-gallon tank rated at 5 CFM will work, but keep in mind, if you start to make longer cuts, your compressor will not be able to keep up.
If you’re a novice hobbyist or interested in utilizing a plasma cutter for occasional home projects or artwork, a smaller plasma cutter will be a good choice for you.
Plasma cutting is an incredibly high-performance tool that requires significant air pressure in order to work. Selecting the correct air compressor for your machine will largely depend on what you’re using it for and the size of your cutter itself.
When considering CFM, it’s best to add a 50% fudge factor to the plasma cutter’s requirements or, for hobbyists and standard users, selecting an air compressor that can deliver at least 4 to 8 CFM at 90 to 120 PSI.