TIG or Gas Tungsten Arc Welding is the preferred form of welding used by professionals today. TIG welding results have a good finish and high strength. While it does require some skill to operate, it is only because the filler metal is fed using the free hand. For welds that do not require a filler metal, TIG is as easy as any other form of high-temperature welding.
If you are looking to purchase a new TIG welder, look out for AC/DC TIG welders that are available in almost all welding supply shops in Australia. Used by amateurs and professionals alike, AC/DC welders are easily the most versatile of all welding equipment.
Most jobs require you to work with more than just steel. Different metals like aluminium, nickel, copper, alloys, require different kinds of power output. DC is used for metals like steel and titanium while AC is the preferred choice for metals like aluminium. An AC/DC welder allows you to work with the widest range of metals.
The welder should have the option for balancing the output current when in AC mode. Breaking through the oxide layer to ensure a clean weld requires the electrode to be positive (EP). However, this can heat up the electrode quickly. AC lets the electrode to be made negative again (EN). AC balance allows a user to adjust the ratio of time between EN and EP. This means control over the balance between penetration and cleaning as well as regulating the size of the weld bead. Modern AC/DC TIG welders usually have the auto-balance function built in. The ability to manually control the balance can be extremely helpful for welding metals with low melting points such as aluminium and magnesium.
The welder should also have the option for high-frequency AC or square wave output. The primary benefit is avoiding rectification, where the arc stops as the electrode changes polarity with a regular since wave output. With square waves or at high frequencies, this problem can be avoided. It also allows a user to lay down a narrow weld bead, increasingly work speed by over three times compared to using a welder without high-frequency output.
If you regularly work with thin sheets, particularly thin aluminium sheets, consider a welder that has options for low output current. Arc stability is extremely important when working with output currents as low as 10A. Most AC/DC TIG welders have output ranges that start around 20A or higher.
It is important to evaluate your needs and plans before investing in a welder. An AC/DC TIG welder gives a lot of legroom to manoeuvre and even avoid having to buy two different welders.