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.
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.
Getting the air supply, cutting capacity and portability right for your workshop is easier with some guidance up front, and that's the kind of buying question the team at Tec Products Ltd are set up to help with.
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.
The abrasive material itself matters as much as the shape. Discs formulated for steel typically contain aluminium oxide, while stainless steel usually calls for an inox-rated disc that's free from iron, sulphur and chlorine contaminants that could otherwise cause surface corrosion on the stainless. Aluminium and other soft, non-ferrous metals need their own dedicated abrasives too, since standard steel discs tend to clog quickly and produce a poor finish on softer materials.
Portability and power supply matter as much as the process itself. A stick welder will run from a generator or a domestic supply in places a gas bottle can't easily follow, while MIG and TIG set-ups need a gas cylinder and, for anything beyond light-gauge work, a heavier electrical supply. Workshop layout, the materials you weld most often, and how frequently the machine needs to travel are all worth weighing up before settling on one process.