Cutting And Grinding Discs: Matching The Abrasive To The Job

Abrasive discs look interchangeable on a shelf but perform very differently depending on what they're made from and what they're used on. Cutting discs are generally thin, designed to slice through material quickly with minimal heat build-up, while grinding discs are thicker and shaped to remove material from a surface or clean up a weld, rather than cut all the way through it.

Flap discs sit between cutting and grinding in terms of use, combining overlapping abrasive flaps to blend welds, remove coatings and finish surfaces with more control than a solid grinding disc. Every disc also carries a maximum operating speed printed on it by the manufacturer, and checking this against your angle grinder's rated speed is a basic habit worth building into every new batch you open.

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.

Welding produces fume made up of fine particulates and gases, and the composition varies depending on the process, the filler material and any coatings on the base metal. Fume rises from the arc and, without adequate control, can build up in the breathing zone of anyone working nearby, which is why extraction is treated as a core part of workshop set-up rather than an optional extra.

An auto-darkening welding helmet uses a liquid crystal filter that switches automatically from a light state to a dark shade the instant it detects an arc, then reverts once the arc is gone. This replaces the older habit of flipping a fixed-shade visor down and up by hand, which meant either welding equipment blind for a split second or lifting the helmet to check your position before striking the arc. 3M Speedglas is one of the ranges we point people towards most often for this, alongside other options across different budgets.

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.