Cutting Ferrous Materials: Use Compressed Air

Compressed air is the most common choice for cutting ferrous materials such as mild steel.

Why compressed air works best:

Compressed air contains oxygen, which enhances the cutting process on carbon steel through an exothermic reaction. This helps the arc cut more efficiently and improves cutting speed. It also provides good cut quality at a low operating cost, since air is readily available and doesn’t require bottled gas. While it can produce some oxidation on the cut edge, compressed air remains the most practical and widely used option for steel fabrication. For general steel cutting, compressed air offers an excellent balance of performance, speed, and affordability.

Cutting Non-Ferrous Materials: Use Nitrogen

Nitrogen is a preferred choice for cutting non-ferrous materials, including stainless steel and aluminum.

Why nitrogen works best:

Nitrogen is an inert gas, meaning it does not react with the material during cutting. This results in cleaner edges with minimal oxidation, which is especially important for stainless steel and aluminum applications where surface quality matters. Nitrogen also produces a stable arc and helps reduce dross, leading to improved edge finish and less secondary cleanup. These benefits become more noticeable on thicker materials or when high-quality cuts are required. For applications where appearance, precision, and minimal post-processing are important, nitrogen delivers superior results on non-ferrous metals.

Choosing the Right Gas

The best plasma gas depends on the material:

Mild steel: Compressed air for cost-effective, fast cutting

Stainless & aluminum: Nitrogen for cleaner edges and reduced oxidation

Matching the gas to the material helps maximize cut quality, improve consistency, and get the most out of your plasma system.