TIG (or tungsten inert gas) welding is also known technically as GTAW or gas tungsten arc welding was developed in the 30s and was widely used during WWII to weld aircraft parts. TIG welding makes use of a tungsten electrode which transmits the electric current to the welding arc and a filler material is used for reinforcement or build-up. Usually, an inert gas such as argon is used to protect and cool the tungsten, as well as the weld puddle.
An air-cooled TIG welder is lightweight and is less expensive compared to a water-cooled one. TIG welders can use both AC and DC current. AC current is usually used while welding aluminium, while DC current is used for welding steel. The TIG welder can be used for stick welding also. The TIG welding process essentially makes use of an electric torch, where the filler rod is fed into the molten weld puddle.
Parts of the TIG Welder
However, before you actually use a TIG welder, it is a good idea to familiarise yourself with the parts of the welder and their function. The work lead is usually attached to the workpiece of the metal surface where the workpiece is placed. This lead cable has the TIG welding torch on one end. There is a small line which carries the inert gas like argon, which essentially acts as the flux coating on the electrode and protects the weld from any contaminants. You will also require a regulator and a gas bottle.
The welding torch comprises several parts. The electrode of the torch is usually made of tungsten and it does not burn like the filler rod. The tungsten electrode can be shaped into a ball or sharpened depending on whatever you are welding. The electrode is usually held in a copper collet, which allows you to adjust the length of the electrode protruding from the cup and the collet has holes which allow gas to pass into the collet and surround the electrode.
The TIG welder has a throttle that allows you to control the amperage and also control the heat. The balance control feature is extremely important for aluminium welding and controls the cleaning and penetration. The more the balance, the greater the penetration you get.
TIG Welding Process
TIG welding is very similar to oxy-acetylene torch welding where the torch is held in one hand and you feed the filler rod using your other hand. Usually, a 4043 alloy is used as a filler rod for welding aluminium; however, if you are going to anodise the parts, then it is better to use a 6356. Use a filler material that has a copper coating to prevent rusting when you are welding steel using TIG welding.
To begin welding, get some clean metal scraps together. You need a metal top table or a metal plate which is fixed firmly on the table. Sit comfortably with your foot pedal within comfortable reach. It is extremely important to wear protective welding gear like coveralls or a long-sleeved shirt, leather gloves, shoes and a welding helmet and goggles.
You must set the correct polarity depending on the metal you are welding and choose the welding rod which is appropriate. Ensure that you turn on the gas bottle and set the regulator to around 20 cubic feet/hour. Then ensure that the tungsten has the right type of point according to the metal you are welding. Press and release the foot pedal, while holding the welding torch away from your body. Now, you are all set to start welding. Use different feeds of the rods to heat and get some practice on the metal scraps before you actually start welding.
While this article may not make you an expert TIG welder, it will definitely help you understand what TIG welding is all about and how it works and why you should get a good quality TIG welder.