Tips For Plasma Cutting Aluminum – Understanding Aluminum Cutting Compared To Steel Cutting

Not Getting The Right Result When Plasma Cutting Aluminum?


Cutting aluminum has some unique challenges compared to cutting steel or other common metals, particularly regarding the crack sensitivity and chemistry. The techniques and best practices for cutting aluminum are very different than those for cutting steel. In some cases, cutting aluminum needs to follow a particular procedure. Important factors when cutting the material include a proper cutting technique and gas selection.

Potential Hazards With Plasma Cutting Aluminum

When aluminum is put into water it produces the highly flammable hydrogen gas. Starting to see the potential danger here?

It is then very important to regularly remove:

  • the pieces of aluminum that fall into the water,
  • as well as the little bits of molten aluminum produced by the plasma arc.
  • Install a bubbler

This is because the longer the metal is in the water, the more gas it will produce and so over time you will have a large build up of aluminum creating lots of gas that could eventually explode on you.

The Challenges Of Cutting Aluminum

A characteristic of dry cutting aluminum is the amount of dust that it creates during the cutting process. You may have to then spend some money on a system to help remove that dust. An alternative to this is to plasma cut aluminum over a water table instead. Or, if you are using a hand held plasma cutter you can get a smaller water table for hand held plasma cutters

What Is The Best Gas For Plasma Cutting Aluminum?

A common problem seen plasma cutting aluminum is that you may not get a clean cut and have to spend a lot of time cleaning the edge down.

This is primarily due to the type of gas you are using. Plasma cutters generally just need clean compressed air to clean cut other metals. However, if you want a more precise clean cut when it comes to aluminum you will need to use an inert gas such as:

  • An argon/helium mix
  • or nitrogen
gas selection for plasma cutting aluminum

Here Are Some Common Tips For Aluminum Cutting With A Plasma Cutter

  • The balance between the travel speed and amperage is key. Move the torch as fast as possible without moving so fast that the arc doesn’t penetrate the metal.
  • Move the torch following the correct direction to cut out the pattern. As a result, any slag that you do have will be on the scrap metal, but not on the finished piece.
  • If you plan to trace a template, a drag tip is a necessity.
  • Aluminum becomes VERY sticky when it gets warm.  Ensure that the air source is correctly connected to the plasma cutter and the air source is rightly in place. In many cases, the plasma cutter can’t be switched on unless the air source is put into the socket.
  • It is essential to place the torch correctly as the electric waves passing through these arcs will melt the aluminum sheet to liquid.
  • Consider a plasma cutter depending on the thickness of the aluminum sheet. If you plan to cut thick aluminum sheet, your plasma cutter should feature a wider gap and bigger arcs among them.
  • Take into account the high-speed machining: higher rates of feed (25 inches/min 635mm/min), small depth of cut (0.030"/0.75mm MAX).
  • Avoid dragging the plasma cutter on the surface of the aluminum sheet. It may damage the machine forever. Hold it above the area you plan to cut.
  •  It’s convenient to sketch it out first if you intend to cut a large chunk of aluminum sheet and then use the plasma cutter. Use a metal market to draw out the line.

How Do You Know If You Did A Good Cut?

Possibly, the best way to understand that you did a good cut is to take a look at the aluminum piece itself. The part you’ve just cut should features drag lines on it that travel in the opposite direction of the path that you cut it.

If you cut it properly following the correct speed, these draglines should be a 15-degree angle. If they are not, the reason is that you were moving either too slow or too fast.

In general, if you cut too fast, you’ll find the sparks flying on the top of the metal.

If you cut too slowly, the quality of the cut won’t be as excellent, and it may be less accurate or broader than you intended.


Hopefully, after reading this article, you will be more confident with plasma cutting aluminum.

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Ronald Wilson

I’m Ronald, Specialist engaged in the manufacture of fabricated metal products. I’ve been involved in the fabrication industry since 1998. To continue my love in welding and to share my experience I've formed a research team and have created this website for our valuable customers.

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