Plasma Cutting Explained: What To Consider Before You Invest

Plasma cutting uses a jet of ionised gas, usually compressed air, forced through a nozzle at high speed and heated by an electric arc to a temperature hot enough to melt through electrically conductive metal. The molten material is then blown clear by the same jet, leaving a narrow, clean cut. Unlike oxy-fuel cutting, plasma works on any conductive metal, including stainless steel and aluminium, not just carbon steel. Hypertherm is the plasma cutting brand we get asked about most, and it's worth understanding the basics before comparing specific units.

If you're weighing up options for your own workshop, from portable units to fixed installations, it's worth talking through the layout with a supplier who stocks a range of systems, such as fume extraction systems.

Helmet choice comes down to the mix of processes you run and how much you're prepared to spend for extra sensors or a wider shade range, and it's a straightforward conversation to have with a stockist that carries several options, including fume extraction systems.

A reliable, adequately sized compressed air supply is the part most first-time buyers underestimate. Undersized or contaminated air, whether from moisture, oil or an undersized compressor, is one of the most common causes of poor cut quality and shortened consumable life, so it's worth checking a machine's air requirements against what your compressor can actually deliver before you buy, not after.

Surface flatness and tolerance are the starting point, but fixturing is what turns a flat plate into a genuinely useful tool. Tables with a grid of holes or T-slots let you bolt down clamps, stops and jigs in repeatable positions, which speeds up repetitive fabrication and makes it far easier to hold parts square while tacking. A table without any fixturing options usually ends up needing extra clamps, magnets or improvised supports to achieve the same result.

Switching speed, the time the filter takes to darken once it detects an arc, is worth checking against how you actually work rather than assuming faster is always better for every budget. For most general fabrication and repair work, a mid-range auto-darkening helmet with a sensible shade range covers the vast majority of jobs comfortably.