Straight answers to the questions people ask most when choosing a ready-to-weld inverter TIG package, from portable single-phase units to heavier pulse power sources.
What does ready to weld mean on a TIG package?
A ready-to-weld package normally bundles the power source with the torch, earth lead and clamp, and usually a gas regulator and hose. The idea is that you only need to add shielding gas, tungsten and filler to start work.
Contents differ from package to package, so check the description for the torch length, the cooling type, any remote control, and whether consumables are included. Also confirm the supply the machine is built for, because some packages are single-phase and others are three-phase.
Do I need AC/DC or will DC be enough?
DC machines handle steel, stainless steel, copper and most other common metals, and are often lighter and simpler. AC/DC machines also weld aluminium and magnesium alloys, because the alternating current breaks up the tough oxide skin.
Choose DC if your work is steel and stainless only. Choose AC/DC if aluminium is likely to feature, even occasionally, as AC capability is built into the machine and is not normally something you can add later; ask your supplier if unsure. AC/DC machines usually have extra controls for balance and frequency, so allow time to learn them.
What is pulse TIG and when is it useful?
Pulse TIG alternates the current between a high peak and a lower background level, many times a second or slower. The weld pool heats during the peak and cools slightly in the background, which gives better control of heat input.
It is useful on thin material, on out-of-position welds, on joints with varying fit-up, and where you want to limit distortion. It can also give a neat stacked-dime appearance. It is not required for everyday TIG, but it is a valuable option for fine and critical work.
Should I choose an air-cooled or water-cooled package?
Air-cooled packages are lighter, simpler and enough for most light and medium fabrication at moderate current, especially if you weld in short runs.
Water-cooled packages add a cooler unit with a pump and tank, which keeps the torch cooler at higher currents or during long welds. They are worth considering for heavier sections, production work or hot environments. The torch must match the cooling type, and a water-cooled torch run without coolant can be ruined quickly.
Can the same machine be used for stick welding as well?
Many inverter TIG machines also include a stick (MMA) mode, and some are sold as multi-process machines that also offer MIG. Stick mode is handy for outdoor work, rusty or dirty material and site repairs.
Check the specification for the processes included, the maximum current in each mode, and what leads or accessories are needed. A multi-process unit can be a good compromise, but a dedicated machine usually offers more refined control in its main process.
What input supply do these machines need?
Smaller inverter packages are usually single-phase and often multi-voltage, so they can run from both a lower-voltage site supply and standard mains. Larger power sources are often three-phase and suit workshops that have a three-phase supply.
Check the rating plate and the manual for the voltage range, the required fuse or breaker size, and the cable rating. Output may be reduced when running on the lower supply, and an extension lead must be rated for the load.