Last Updated on May 17, 2022
TIG welding (or tungsten inert gas welding) is an extremely popular type of arc welding which employs un-consumable tungsten electrodes to make the weld. In this process, inert shielding gases like argon and helium are used to safeguard the weld region as well as the welding electrode from oxidation and other forms of contamination.
This type of welding is done manually and is often utilized for important weld connections when tiny and accurate welds are needed. It is also used to join thin portions of non-stainless steel metals such as aluminium or different alloys of copper. Electricity is transferred through the arc by the continuous power source across columns of ionized gas and vapours of metals.
Tungsten is sturdy but brittle, and it is mildly radioactive. Relative to other metals, its flexibility of application is restricted. TIG welding, in contrast, converts tungsten to electrodes (un-consumable) which serves as the source of the welding arc.
Lastly, TIG welds will typically require welders to utilize both hands, one that handles the TIG torch and another that adds filler metal onto the welded joint. TIG welding is tough to master due to the numerous complexities of the process, yet the procedure guarantees high-quality welds every single time.
The Pros and Cons of opting for TIG welding
Now, let’s take a look at the list of pros and cons for opting to use TIG welding as compared to other techniques:
|· The operator has much better control over the weld.
· TIG welds are relatively a lot stronger and more precise than most welds.
· The welding material options for TIG welding are numerous.
|· Welders can find it more complex than most other forms of welding.
· This process is more time consuming compared to other welding techniques.
The 3 ways to Start a TIG Arc
Now that we’re well-acquainted with the concept of TIG welding, and the benefits and drawbacks that this technique brings along, it is time to consider the 3 starting methods for a TIG arc. These are, namely:
- The Scratch Start Technique
- The Lift-arc Technique
- The High Frequency (HF) Ignition Technique
In the subsections that follow, we will be discussing each of these 3 techniques in greater detail.
The Scratch Start Technique
This technique is a more traditional way of initiating an arc. The initiation process entails “flicking” tungsten (almost molten) over the metal till the arc forms. This starting process works quite well and enables practically all DC stick welders to convert into TIG welders easily.
However, starting from scratch entails certain disadvantages. When the arc is ignited, the tungsten nearly instantaneously becomes heated. Additionally, tiny fragments of tungsten get lodged in the welding mix, which may lead to structural issues and pollution in the welding mix.
In general, the scratch technique is a pretty reliable method of initiating TIG welds. This method is most often used for ordinary welding jobs. Despite its utility, though, this method is now considered to be a lot less clean compared to other arc starting methods such as arc lifting and high-frequency techniques.
The Lift-Arc Technique
“Sometimes, people use both “lift start” and “scratch start” interchangeably. This, of course, is a mistake. These two TIG starting techniques are inherently different – In the case of the lift technique, welders rapidly lower tungsten so that it touches the metal. After that, it is quickly raised to draw the arc. This movement gives the appearance of the scratch technique, but it is really a cleaner technique that involves less touch with the metal.
The user of the lift-start technique utilizes a pedal to control it. However, no arc jump exists in the middle of the metal and the tungsten tip. Instead of that, the worker places a cup atop the metal and presses down on the pedal before finally rotating it until it is in an upright position. This is to allow the tungsten to make contact with the metal before lifting it up in a gentle, fluid motion.
In comparison to the scratch starting technique, this method yields fewer contaminants and preserves the tungsten tip well. However, of course, this method is not fully free of contamination, especially due to the fact that tungsten is present. Generally speaking, the lift start technique is a much superior method of starting an arc compared to the scratch start method – especially for stainless steel. Note, though, that aluminium is not a viable candidate owing to the metal’s tungsten.
The High Frequency (HF) Ignition Technique
Due to the effectiveness and cleanliness of this process, many operators believe that the HF or high-frequency starting technique for TIG welds is the best among the 3. This is even evidenced by the fact that over the years, this technique has become highly popular (the most among the 3). This technique involves the generation of a high-frequency arc, which ionizes the air and closes the gap in the middle of the tungsten tip and the workpiece. As a consequence, this is a contactless process with minimal chances of any contamination.
While this isn’t the only way to start an arc in TIG welding, it is certainly a highly viable choice for more affluent TIG welders who can bear the cost of this sort of costly equipment and want to work with the up and latest arc technology.
When should each technique be used?
Now it is time to discuss when (if at all) you might need to use one of these 3 TIG arc starting techniques.
The scratch starting technique involves the use of cheap, affordable equipment, and it is also the most traditional starting technique among the three techniques. While the general trend for this sort of a start is declining, this technique is still pretty commonly used for basic repairs of automotive machinery since they produce clean welds.
In the case of the Lift arc starting technique, its most popular use is in welding operations for various industries like the pharmaceutical and food industries. In addition to this, one particularly popular use of this technique is during the welding of pipes.
Finally, due to the advanced technology and high precision it offers, the general trend can be seen shifting towards the HF ignition technique for starting a TIG weld. This means that welders (those who can afford the required equipment, are shifting to HF ignition techniques for all sorts of TIG welding operations.
TIG welding is an extremely popular branch of arc welding that employs tungsten electrodes to make its welds while inert gases ensure that the weld region is safe from any contamination. In general, there are three arc starting techniques for TIG welding. In the table below, we have listed these three techniques alongside their most popular use:
|Starting Technique||Popular Usage|
|Scratch Start||This method is more traditional, and it is losing its popularity. Still, it is quite widely used to repair equipment and machinery in the automotive industry.|
|Lift-Arc||Popularly used for welding pipes and has multiple uses across the food and pharmaceutical industries.|
|HF ignition||The general trend for all sorts of TIG welding operations is inclining towards this technique.|