Using 2T and 4T in TIG - Part 1
Although the vast majority of TIG machines sold in the US are sold with a foot pedal, the US and a few other countries are the exception, rather than the rule. We’ve discussed this before, but it’s worth discussing again, as repetition promotes retention right? Although people frequently want all the bells and whistles on their new inverter AC/DC TIG machine, or at least all they can afford, few realize that these bells and whistles are designed for advanced features that are not used with the foot pedal. Items like Start amps, Up slope, Down Slope, and End amps are features that are tied directly to using a TIG machine without a foot pedal. These are primarily designed for use with the torch switch in either the 2T or 4T settings.Start amps, or beginning/initial current, as it is sometimes referred to, is the only feature that would often be employed if used with the foot pedal, as it doubles in most TIG machines as a “Hot Start”.This offers a brief burst to heat up the weld and establish the arc. However, as used with the torch switch, Start amps serves as the beginning point of the amperage provided at the start of the weld. In 2T, this is accomplished automatically as the torch switch is simply held. In 4T this is accomplished by pressing the switch as well. But the start amps will remain at the set level until the torch is released to start the next phase of the weld cycle.If used with an Everlast TIG welder in 4T mode, this will cause the welder foot pedal to only act as on off switch, and will limit/prevent the control of the amps, and will prevent normal use of the machine. So in order for 4T to work at all, the torch switch or 2T (or relevant pedal mode) must be selected.