When shopping for modern TIG welders or multi-process welders, you’re likely to come across a feature called 2T/4T Mode. The 2T and 4T refer to two distinctly different modes of torch switch operation on a TIG welder. If you’re new to welding, you may not understand what these features are and why they’re so valuable. In short, these modes affect how the welder starts and stops the arc, providing flexibility and control to the welder.
The choice between 2T and 4T modes depends on the specific welding task and the welder’s preference. 2T is simpler and provides immediate control, while 4T offers enhanced control and reduces fatigue during longer welding sessions. The value of the 2T/4T features is the ability to quickly and conveniently switch between the two modes.
Here’s a brief explanation followed by a quick video that helps visualize the differences:
2T Mode (2-Touch)
In 2T mode, the operation is the simpler of the two and involves just two steps.
1. Press and hold to start – The welder presses the torch button to initiate the welding process. When the button is pressed, the arc starts, and welding begins.
2. Release to stop – The welder releases the button to stop the welding process. When the button is released, the arc extinguishes, and welding stops.
2T Mode is ideal for short, quick welds. It’s useful in situations where immediate control is necessary, such as spot welding or tack welding. This mode is straightforward and is often used for shorter welds or when the operator prefers manual control over the start and stop of the arc.
4T Mode (4-Touch)
4T mode is a more complex function but offers greater control, especially for longer welds.
1. First press – The operator presses the torch button to start the arc. The button can then be released while the arc remains on.
2. First release – After pressing and releasing the button, the arc continues to stay on. This allows the welder to weld without holding down the button continuously, reducing finger fatigue.
3. Second press – To signal the end of the welding process, the welder presses the button again. This typically initiates a “downslope” period, where the current gradually decreases to avoid creating craters or defects at the end of the weld.
4. Second release – Releasing the button after the second press completely stops the arc, finishing the weld.
4T Mode is advantageous for longer welds where holding the button continuously would be tiring. It’s also preferred when a smooth finish is required, especially in professional and high-quality welding applications.