A gas lens sits in place of the standard collet body and uses a fine mesh to straighten the shielding gas flow into a smoother, more laminar stream around the arc. This generally allows a longer stick-out from the cup without turbulence pulling in surrounding air, which is particularly useful when working in tighter joints or awkward positions where the torch needs to sit further back from the work.
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.
Shade range and sensor count are the two specifications that matter most in daily use. A wider variable shade range lets one helmet cover a broader spread of processes and amperages, from low-amp TIG work through to higher-output MIG or MMA, without swapping cartridges. More sensors generally mean the filter is less likely to miss a low-angle arc or a strike caught at an awkward viewing angle, which matters most for TIG welding where the arc can be harder for a sensor to pick up cleanly.
TIG welding relies on a handful of small consumable parts inside the torch that have an outsized effect on how the arc behaves. The tungsten electrode itself doesn't melt into the weld; it simply carries the arc, and tecproducts.co.uk different tungsten types, distinguished by their alloying elements, suit different current types and materials. Getting the wrong tungsten for the job typically shows up as arc wander or poor arc starts long before it shows up anywhere else.
The figure changes with output. Turn the amperage down and the duty cycle climbs, because the internal components are working less hard. This is why a welder can feel completely different in a busy production environment compared with occasional home workshop use: someone welding continuously through a shift needs a much higher duty cycle at their working amperage than someone doing short repair jobs a few times a week. It's the kind of spec worth comparing properly across brands such as Kemppi and EWM, not just reading off the headline amperage figure.
If you're still working out which process fits your workload, it helps to talk it through with people who field these questions every day rather than guess from a spec sheet, and the team behind welding supplies North Yorkshire in Thirsk deal with exactly this kind of query on the advice line.