Parts and accessories for an AC/DC TIG inverter power source: torches, torch heads, return leads, remote controls, trolleys and carry cases, and how to pick the right one.
How often should I inspect the torch and leads, and what am I looking for?
The welder is responsible for daily equipment checks and for reporting defects, and employers should run a programme of regular checks on welding sets. Look for cuts or soft spots in cable covers, cracked torch insulation, kinked gas hoses, loose or discoloured connectors and leaks at fittings.
Do this with the machine switched off and the torch cooled. There is no fixed interval for testing; it depends on the equipment and where it is used, so set one in your own risk assessment. Visual examination is an essential part of the process, although some defects can only be found by testing, and damaged equipment should be repaired by a competent person before it is used again.
What should I check on a return lead and earth clamp?
The insulation on welding and return leads should be undamaged and the conductor thick enough to carry the current safely. Connectors should be clean, undamaged and rated for the current, and the insulation on clamps and plugs should be undamaged too.
The clamp should grip bright, clean metal, so remove rust, paint or primer at the contact point, because a poor connection can overheat. Place the clamp as close to the work as is practical. Look for worn clamp jaws, weak springs, damaged insulation and loose or warm plug connections, and replace anything that is worn.
Does welding aluminium on AC change which torch parts I need?
Aluminium needs AC output because the half cycle with the electrode positive breaks up its tough oxide film. That half cycle also heats the electrode strongly, so the electrode type and diameter should suit the current and your machine.
The torch parts are mostly the usual ones: a collet and collet body or gas lens, a cup and a back cap. Choose the cup and body for joint access and the stick-out you need, and keep the electrode diameter matched to the current. Check the power source's manual for recommended electrodes and test on scrap first.
What should I look after on a water-cooled torch and cooling unit?
Check the coolant level and look for leaks before welding, and inspect hoses and fittings for cracks, bulging, thin walls, soft spots or loose connections. A leaking hose or torch can create a shock hazard, so repair or replace the affected part before you weld.
Use only the coolant the cooling unit's maker specifies, and never run the torch without coolant. Car antifreeze can clog the narrow passages, and hard tap water should be avoided. Keep the cooler's air passages clear of dust and make sure any flow or level protection works. Follow the maker's manual and service intervals.
How do I choose the right cable size and length for a return lead?
The lead has to be thick enough for the highest current you will weld at, and the conductor must carry the current safely. Connector and insulation ratings matter as well, so compare the cross-section and current rating shown on the lead or in its data with the power source's maximum output.
A longer lead adds resistance and voltage drop, so it is often sensible to step up a size for long runs, and to use the length that suits your working area and no more. An undersized lead tends to run warm. Follow the maker's cable guidance, and ask your supplier if you are unsure.
What does the duty cycle on a torch or power source mean?
Duty cycle is the share of a ten-minute period that equipment can run at a stated current before it needs to cool. For example, a 60 percent rating at a given current means about six minutes of welding followed by four minutes of rest in each ten.
The rating is tied to a specific current, so running at a lower current usually allows a higher duty cycle, and running above it risks overheating. Always read the figure on the data plate or in the manual rather than assuming it, and remember it is quoted for stated test conditions such as ambient temperature.