TIG welding polarity is pretty straightforward. Once you set up your machine, you shouldn’t have to change the terminal connections ever again – unless you want to stick weld.
Newer inverter machines will allow TIG polarity changes while the machine is on. These newer machines often have digital readouts that allow for quick amperage changes and TIG polarity changes. However, older transformer machines can get severely damaged if you change polarity while the machine is on. You can read more on welding machines in our guide here.
TIG Welding Polarity Options
Electrode Negative TIG (DC-)
TIG welding steel, stainless steel, titanium and chromoly requires DCEN. Opposite of most Electrode Positive stick welding, DCEN is a negative current or “Direct Current Electrode Negative”. This means that the torch hose is attached to the negative terminal of your machine, and the ground clamp lead is attached to the positive terminal on your machine.
Dinse Style Connectors are most common in modern day machines and allow for quick changes if needed. Higher end machines such as the Miller Dynasty will allow for polarity changes with the click of a button. This means that you don’t have to physically switch the terminal connections.
Alternating Current TIG (AC)
Aluminum TIG welding will require alternating current or AC, in which the machine is constantly reversing between positive and negative currents. Lower end machines usually don’t have this feature. It is essential for TIG welding aluminum, but isn’t as common for hobbyists or general home applications. However, If you plan on TIG welding aluminum, make sure your machine has AC. A good aluminum TIG welding video can be watched here from welding tips and tricks.
For all things TIG welding, this book helped us out a lot through school and through the earlier parts of our career. Detailed illustrations and in depth chapters help explain just about anything TIG related. We were required to read chapters for our school work, but we kept the book to use as a long term reference.
Electrode Positive TIG? (DC+)
There is rarely a reason to run positive polarity (DCEP) for TIG welding. It will burn up the tungsten and ruin your weld. However, you can use positive polarity to your advantage in one key situation. If you need to ball your tungsten for aluminum TIG welding, you can initiate a quick arc on a positive current. Generally just do this for a split second, and then stop. This will form a nice ball at the end of your tungsten. Then, you can switch to AC and begin aluminum welding.
Newer machines will tend to ball the tungsten automatically on AC current, but the positive polarity trick listed above can be useful on older transformer machines. A rounded tungsten performs better on aluminum than a sharpened tungsten.
Switching your Stick Welder to TIG
If you want to run a scratch start TIG setup off your existing stick welder or engine drive, simply switch the DCEP (positive) setup to a DCEN (negative) setup. Switch your leads to opposite terminals – so your stinger lead is now negative and your ground clamp is now positive. Then, clip the stick stinger to your power block adapter for your hoses, and clip your ground to your work piece. You can read more on Scratch Start TIG supplies here.
Some lower end machines will have the TIG leads/hoses hardwired in, with no option for adjustability. This means you can start TIG welding right away. However, if you want to stick weld, you’ll need some machine modifications.
For more TIG welding info, click here.