Welding equipment
Power sources, torches, helmets and accessories — choosing them and keeping them running.
Two questions dominate this section: what to buy, and why the thing you already own has stopped behaving.
On buying, four numbers decide it — maximum current, duty cycle at a stated current, what the supply has to provide, and what the arc controls offer. Everything else on the box is marketing, and the parts that determine whether a machine is pleasant to use are the ones nobody photographs: the leads, the clamp and the wire feed unit.
On faults, the pattern is consistent. Almost everything that goes wrong is dust, a loose connection or a consumable, and working from the outside in — clamp, leads, connectors, consumables, then the machine — resolves most of it without opening anything.
- Choosing a welding machine A 16 A socket supports about 120 A of stick welding; 250 A needs three-phase. Compare machines at 100 % duty cycle, check I₁max, PFC and the leads.
- Welding helmet How auto-darkening helmets work, what the four EN 379 numbers mean, and which shade to set for each process and current.
- MIG/MAG torch consumables What 250 A at 60 % means, why a torch runs hotter in M21, M6 vs M8 tips, CuCrZr, nozzle choice and liner care — with a worked sizing example.
- Servicing and typical faults Earth clamp, contact tip, drive rolls, liner, dust: what to check yourself in half an hour. Fault table, service schedule, EN IEC 60974-4 test.
Frequently asked questions
How many amps do I need?
Roughly 40 A per millimetre of the thickest single-pass weld. Up to 5 mm, a 160 A machine; for 10 mm structural work, 200 A. Buying more than the supply can feed just gives you a machine you cannot run at full output.
What does the duty cycle on the box actually mean?
Minutes of welding in every ten. "200 A" on the front usually means 200 A at 20 % — two minutes in ten. The figure worth comparing is the current at 60 %, which is on the rating plate rather than the box.
The machine cuts out after a few minutes. Is it broken?
Probably not. That is the thermal protection working, and it means either the duty cycle is being exceeded or the air path is blocked with dust. Both are ordinary, and both are fixed without opening the case.