When you are welding in your workshop, you want to establish a welding current between the base metal and electrode, referred to as striking an arc. There are different methods to striking an arc which includes tungsten ionized gas (TIG) welding. When heat or high-frequency voltage is applied to the tungsten gas in the TIG welding process, it can be ironized and melts at a very high heating point. As a result, the tungsten electrodes will heat up and not melt, unlike other welding processes.
Tungsten is considered to be a non-combustible kind of welding because it can resist heat without melting. However, MIG and stick welding are deemed combustible welding because when heated to a melting point, it melts and becomes a part of the weld. In welding a pipeline and other exotic metals, TIG welding is the most common method used, less intense, and quieter than the stick or MIG welding.
In TIG welding, scratch starting is almost similar to scratching on a matchbox with a matchstick. Explicitly designed for stick welding, a TIG electrode is fitted into the inverter welder machine. When the gas is turned on, the arc is established once you sweep on the plate surface to make contact. To initiate the arc, scratch start can be used on low-cost equipment, allowing any ac dc tig welder for sale to be used. Scratch start is the oldest method used to start an arc, especially with TIG start welding. It is important to consider or expect some tungsten to be left sticking on the metal during the scratch process.
Lift TIG (Lift Arc)
In the beginning stages of lift arc, the process is similar to scratch start; however, they are different in forming the arc. They both rely on tungsten electrodes to make the initial contact with the metal, but with lift arc, the electrodes are rapidly brought down and lifted immediately to draw up the arc. The lift arc method is consistent and controllable, using DC output instead of high-frequency current.
This method of arc is considered to be much cleaner than a scratch start but also can have tungsten contamination. When using a lift arc, avoid using it on aluminum, as it has a natural affinity with tungsten. If you are near an airfield, where there are frequency issues, phone or computer networks, lift arc starting is common.
High-Frequency Start (HF Arc Start)
One of the most common methods for TIG welding is high frequency (HF) start. The method is in its name; the tungsten electrode is merged into a high-frequency arc machine. This method produces a non-contact start by bridging the gap between the base metal and the tungsten electrode by means of ionizing the air with a high-frequency arc. The most significant benefit of high-frequency starting is clean air, leaving the tungsten uncontaminated. Process piping and pressure vessels are some of many procedures which specify non-contact starting methods to be used. This method would be an excellent option for TIG welding. High-frequency welding is more on the expensive side, and while it’s considered the best method for TIG welding, not many welding systems have HF arc starts incorporated in them.