How Thick Can a Plasma Cutter Cut?

Written By: Liam Bryant

Reviewed By: Russell Egan

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Handheld plasma cutters can cut through mild steel up to 1.5 inches thick, while industrial plasma cutters can cut through steel up to 6 inches thick.

If you’re working with metal often, you’ve probably come across a plasma cutter. Plasma cutters are tools that have been around since the 1960s. They use plasma, or a gas heated to very high temperatures, to cut through powerful metals. Plasma cutters are used anywhere from factories to autobody shops because they cut through metal easily.

However, plasma cutters are used most often for thinner metal sheets such as aluminum. You may be wondering if you can use this tool to cut through thicker metals. The answer depends on the type of plasma cutter you are using, since handheld cutters are very different from massive computer-operated machines.

Here is your guide to finding the right plasma cutter for the thickness your project demands.

plasma cutter

How Thick Can a Plasma Cutter Cut?

It is hard to answer this question because there are so many different types of plasma cutters. 

Smaller machines have less power and will only cut through thinner material. Handheld plasma cutters usually cut material with a maximum thickness of 1.5 inches (38 mm). This is good enough for most DIY uses since you work mostly with thinner metal for at-home use. However, this is not thick enough for industrial usage.

That is why factories and industrial workers invest in far more powerful industrial plasma cutters. These cutters are massive machines that are controlled by computers. They can cut through metal up to 6 inches (150 mm) thick. Most DIY welders won’t experience this power since these machines are too expensive for the average home welder. Still, you usually don’t need to cut this thick material for your backyard welding projects.

What Metals Can a Plasma Cutter Cut?

The thickness of the metal is not the only factor that affects how well the plasma cutter will work. The type of metal you are using also affects the cut’s quality. Plasma cutters do some of their best work with steel, providing a faster, thicker cut. 

However, these versatile machines work with many different metals. The quality of the cut will be different depending on the metal you are working with, and you may need to adjust your technique (and expectations) to get the best possible cut.

The list of metals you can use a plasma cutter with includes:

  • Mild steel
  • Stainless steel
  • Steel alloys
  • Aluminum
  • Carbon steel
  • Copper
  • Brass
  • Ferrous (iron-containing) metals
  • Titanium

This is not an exhaustive list, and you can use plasma cutters with almost any metal as long as you adjust the settings right.

How Does a Plasma Cutter Work?

Plasma cutters seem like such intimidating tools, especially to beginning welders. That is why I also have a guide to using a plasma cutter

It is helpful to understand how these tools work to make using a plasma cutter less intimidating. Plasma cutters work by heating pressurized gas until it reaches a plasma state, which can cut through metal. 

Here is a step-by-step explanation of how these tools work and why they’re able to slice through metal so easily.

1. Plasma cutters have a full gas canister. Plasma cutters are powered by pressurized gas, usually oxygen, argon, or nitrogen.

2. The pressurized gas is forced through a narrow channel. The small opening increases the speed and pressure of the gas, which ultimately increases the temperature. It also concentrates the gas so you can create a directed plasma arc.

3. The gas is exposed to a negatively charged electrode in the plasma cutter. This electrode is very important because it causes a spark. Electrical energy converts to thermal energy, which heats the gas until it reaches the plasma state. Plus, electricity creates a circuit, which directs the plasma into the metal.

4. The charged gas heats until it enters a charged plasma state. The plasma is forced out from the nozzle at a high speed and temperature, melting the metal. The plasma is also charged thanks to the spark from the electrode. When it comes in contact with the metal, it creates a melted pile of slag. The plasma connects to the metal thanks to its charge, which binds to the charge in the metal to create a completed electrical circuit. 

Meanwhile, the rest of the gas that doesn’t turn into plasma flows through separate channels away from the electrode. This gas functions as a shielding gas, which blocks oxygen and moisture from entering the weld and damaging it. 

5. Turning off the plasma cutter breaks the circuit. When you power off the plasma cutter, the electrode is no longer charged, breaking the circuit and cooling the gas.

How to Use a Plasma Cutter to Cut Thick Metal

If you need to cut some thicker metal, here is the best way to get the most out of your plasma cutter. 

1. Make sure you are using the right plasma cutter. If you want to cut a piece of steel several inches thick, no amount of fiddling with the settings on your handheld plasma cutter will make it work.

2. Prepare your set-up and equipment. Working with plasma is dangerous, so you want to protect yourself. Make sure you have a welding helmet and special welder’s gloves. Plasma cutters are hotter than TIG or MIG machines, so you need gloves that can withstand higher temperatures.

3. Adjust the amperage. The higher the amperage, the more powerful the plasma arc will be and the deeper the cut will be. A good rule of thumb is that for every additional 1/10th of an inch (or 3 mm) in thickness, increase the amperage by 10 amps.

4. Cut the metal. A good technique for plasma cutters is holding the tip at a 45-degree angle and dragging it toward you. Make sure sparks are traveling away from you.

Final Thoughts

Plasma cutters are excellent tools for cutting metal. Handheld cutters can cut metals up to 1.5 inches thick, while industrial machines go even thicker.