Plasma Cutting Explained: What To Consider Before You Invest
Matching duty cycle to actual workload, rather than just chasing the highest amperage figure, is the difference between a machine that keeps up with the job and one that keeps tripping out halfway through it, and it's a question worth raising with a supplier before you buy, such as Recommended Web site.
Ambient temperature and airflow around the machine also affect real-world performance. A welder working in a hot, poorly ventilated space, or one that's been boxed in against a wall with no clearance for its cooling fan, will hit thermal cut-out sooner than the same machine used with proper clearance in a cooler environment. Keeping vents clear and giving the unit room to breathe protects both the duty cycle you paid for and the components inside.
MIG (metal inert gas) welding feeds a continuous wire electrode through a gun, shielded by a gas supply, which makes it fast and relatively forgiving for general fabrication, sheet steel and repair work. Jasic's MIG range is one of the more popular starting points here, covering entry-level compact units through to higher-output machines as work scales up. TIG (tungsten inert gas) uses a non-consumable tungsten electrode with a separate filler rod, giving a slower but tidier result that's favoured for thinner materials, aluminium and stainless steel where finish quality matters. MMA, or stick welding, strikes an arc from a flux-coated electrode and needs no shielding gas at all, which makes it the most portable option and a common choice for outdoor or on-site work on thicker steel.
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.
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.
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.