Do Plasma Cutters Need Gas?

When you need to cut metal instead of weld it together, a plasma cutter is the best tool you can have on hand. A plasma cutter uses the power of plasma, the lesser-known fourth state of matter, to melt metal and cut it into pieces. If you’re unfamiliar with plasma cutters, you might wonder how they work.

Plasma cutters need gas because you can only create plasma by heating pressurized gas until it enters a plasma state. Thus, you have to have a reliable gas supply on hand if you use a plasma cutter. 

Here is everything you need to know about why plasma cutters need gas, including the best type of gas to get.

miller plasma cutter

Do Plasma Cutters Need Gas?

Yes, plasma cutters need gas. Without gas, you are missing the most important component of a plasma cutter—the plasma itself. Plasma is superheated gas that consists of positively and negatively charged ions. 

To understand why you need a gas canister for your plasma cutter, you need to know how these machines work. Plasma cutters create plasma by heating pressurized gas using a negatively charged electrode. The gas is forced past the electrode in a narrow channel, putting it under even more pressure and speed until it changes into plasma. Then, the charged plasma bonds to the metal, creating a complete electrical circuit.

Plasma cutters need a lot of gas to work because you both need enough gas to turn into plasma and more gas to use as a shielding material during the welding. Without gas, a plasma cutter wouldn’t be able to function at all. If you use a plasma cutter in your workshop, ensure you always have an extra gas canister handy.

I recommend this Plasma Cutter by S7. It is very simple to use with plug and play capabilities and can switch input powers between 110 and 220V. I have found it to be very lightweight and portable and can cut up to 3/8 inch through steel. I have tested it with mild steel, stainless, and copper and haven’t had any problems.

What Gas Does a Plasma Cutter Use?

Plasma cutters can use several different gases to do their jobs. Here are the most common ones as well as their different properties. Using the right gas can help you learn how to use a plasma cutter.

1. Compressed Air

If you’re running a DIY plasma cutter in your backyard workshop, the easiest gas to use for your plasma cutter is compressed air. You don’t even have to go out and buy this gas because you have a free supply of air no matter where you look! 

You will have to invest in an air compressor or a plasma cutter with an attached air compressor, but after that initial investment, you won’t have to buy gas again. 

Compressed air seems like it isn’t that special, but it is actually very effective once you run it through a plasma cutter. It can cut smoothly through steel and aluminum. 

However, compressed air is not perfect for industrial uses because it is not as powerful as other gases. It can only cut through metals that are up to one inch thick. Plus, oxidation is more common with this type of gas, which is less of an issue for an at-home project but will affect the quality of the weld on an item you are selling.

2. Oxygen

Another very common gas for plasma cutters is oxygen. Oxygen is the most common gas in plasma cutters because it is the fastest and acts as a built-in shielding gas. It also has the best quality cut, especially for materials such as steel. It works with metals as thick as 1¼ inch. 

However, oxygen is also the most expensive gas. You are saving money by ensuring every cut is high-quality, but if you use your plasma cutter a lot, you may look at other options for lowering costs.

3. Nitrogen

Nitrogen is very similar to oxygen because it also creates very high-quality cuts. Although it is slower than oxygen, it is effective, especially when working with aluminum and stainless steel. It is more durable than oxygen and works well in tandem with other gases such as CO2 and argon.

Nitrogen is the best choice for cutting thicker metals. A high-current plasma cutter and nitrogen combination can cut metals up to three inches thick. 

The only downside is that nitrogen is also pricey, so if you don’t need such a high-powered cut, it’s not worth buying it.

4. Argon-Hydrogen

This mix of gas usually uses 65% argon to 35% hydrogen. Argon-hydrogen is the most powerful gas for plasma cutters, creating a plasma that is hot enough to cut through metals up to a whopping 6 inches thick. It also produces a very smooth cut, making it perfect for plasma gauging, not just cutting.

However, the same qualities that make argon-hydrogen a good choice in some jobs are its downfall in other situations. The high heat is perfect for cutting through thick stainless steel but will damage softer metals such as mild steel. For smaller jobs, the cost of argon-hydrogen is not worth it.

How to Choose the Right Gas

There are four main gases you can use for your plasma cutter. 

To choose the right one, you must consider the metal you are cutting. If you are working with 6-inch-thick pieces of stainless steel, you need argon-hydrogen, which will be too much for a simple sheet of aluminum. 

Also, look at the type of metal you are working with, as different metals react better with different combinations of gas and shield gas.

Another important factor is your budget. While oxygen and nitrogen produce clean, smooth cuts, you can get just as good results with compressed air for a fraction of the price. 

Equipment Needed

To operate your plasma cutter, you need some equipment on hand, including the following:

  • An air compressor (only if you are using compressed air to power your plasma cutter)
  • Gas canisters if you are using a gas other than compressed air
  • Special gloves for wielding a plasma cutter since the heat is higher than for a regular welder
  • The plasma cutter itself

Final Thoughts

Plasma cutters need gas to operate. You can buy argon-hydrogen, nitrogen, or oxygen, but for most DIY uses, plain compressed air from your shop works best as long as it doesn’t have lots of dust or moisture.