TIG welder setup basics - 2T/4T
There are two basic ways to control the amps. The first is with the foot pedal which allows infinite control of amps real time. Though this sounds ideal, it is not a very scientific or controlled way of welding if the protocol for welding a particular joint, or metal type defines a narrow range of amps in which the weld should be conducted. The 2T/4T setting allows the operator to start the weld simply by pressing a trigger or switch located on the torch and use pre-settable features such as starting amps, up slope, down slope, and ending amps to manage the weld from beginning to end. Using the 2T function, the 2T normally indicates a press and hold type of operation of the welder. While the switch is held down, it cycles the preset programming automatically. This works well for some situations that require very little thought or skill. The 4T breaks this cycle up to allow manual initiation of each stage of the arc cycle. Pressing and holding the switch usually starts the arc. Releasing the switch will increase the amps to normal welding amps at the rate selected by the upslope. Pressing once again, will cause amps to begin to decrease according to the pre-set down slope until it reaches the final current, which is used to fill the crater so it won’t crack. Then, the switch is released to terminate the arc. Though this isn’t for everyone, 2T/4T does work well for most other countries in the world. A foot pedal is seldom seen outside of most US based welding shops.