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Answers on the parts that go with a water-cooled AC/DC TIG welder: torch, torch neck, cooling unit, coolant and trolley.
As welding current and duty cycle rise, the torch has to shed more heat. Lower-current torches can normally be gas-cooled, while higher-current torches use larger electrodes and water cooling. Water-cooled torches are usually lighter and more flexible to hold on long welds, but they need a cooling unit, coolant and more upkeep.The point where you should switch depends on the torch rating, how long you weld at full current and the work you do, so there is no single cut-off figure. Check the rating on the torch against the maximum current of your welder, and ask our team if you are unsure.
Ordinary tap water is a poor choice. Dissolved minerals make it conductive, and current passing through it can corrode metal parts and release particles that block the torch. Water on its own also freezes in cold conditions, which can burst the torch and cooler.Use a coolant made for torch cooling circuits, with low electrical conductivity and frost protection, as the cooling unit maker recommends. Avoid car antifreeze unless the maker says it is suitable. Always check the cooling unit manual for the approved coolant and the correct level before you fill it.
Coolant ages, so do not rely only on a fixed yearly change if you weld heavily. A simple routine is to look at the level and colour regularly and to change the coolant sooner if it turns brown, cloudy or has particles in it.Checking the coolant's conductivity at intervals and changing it once it passes a set limit may also be needed, depending on your equipment. Intervals and limits depend on your equipment and how often you weld, so follow the cooling unit manual. When you change it, drain and flush the circuit and bleed the air out before welding.
Aluminium has a tough oxide film, so AC is used. The polarity switches many times a second and the electrode-positive part of the cycle breaks up the oxide. That part of the cycle also puts more heat into the electrode, so the electrode type, diameter and tip shape should suit the welder and the job.This is one reason water cooling suits AC work at higher currents. Choose the electrode to suit the welder and the job, follow the maker's guidance, and match the collet, collet body and cup to that diameter.
Duty cycle is the proportion of a ten-minute period that a torch or power source can run at a stated output without overheating. Running above the rating heats the handle and cable and leads to downtime or damage. A power source normally runs at a lower current for a longer duty cycle.Compare the torch rating with the maximum current of the welder and with how long you actually weld at that level. For heavy production work, choose a torch rated above your normal working current. Ratings are given on the torch or in its data sheet, so check these rather than assuming.
A trolley carries the power source, the cooling unit and usually a gas cylinder, so stability matters. Makers normally give a maximum combined height or load for the trolley, and a stack that is too tall can topple. Check the limits in the trolley manual against the equipment you plan to mount.Secure the cylinder firmly with the straps or chain provided and use only the cylinder sizes the maker allows. Castor brakes are there to hold the trolley still on a level surface, not to make moving it safe. Tighten every fixing after fitting and check them again from time to time.