A front view of our TIG welder....
A front view of our TIG welder. There is a digital display screen to view all the settings. As you can see, the argon bottle is chained to the table. A tipped-over bottle with a broken valve can make your shop a very exciting place. This welder weighs 50 pounds.
What is a TIG welder? You may have heard of Heliarc welding. This is the brand name of one of the first welding machines to use the tungsten (T) electrode with an inert (I) gas (G) process. TIG is the generic name for this process.
The tungsten electrode forms the point of the electric arc. It does need to be reshaped on its end occasionally, but it is not consumed in the process.
The inert gas that flows out of the ceramic cup and around the tungsten shields the arc from the atmosphere. This is necessary because the heat generated will allow the metal being welded to burn. By shielding the weld area with an inert gas such as argon, the oxygen in the air is excluded, thus the weld metal cannot burn.
The TIG process produces the purest welds of any form of welding available. Done properly, there are no contaminants in the weld. Occasionally, for some welds, the inert gas is also introduced to the back side of the weld area to keep contamination away from the weld. TIG welds can be of a quality in which an X-ray won't reveal imperfections.
Everything is in place to...
Everything is in place to weld. The machine has been properly set for the metal to be welded. The argon flowmeter is set. The tungsten has been sharpened. All that is left to do is to move one finger to start the arc. TIG welding is easy because of the amount of control you have over the heat.
Most all TIG welders have a variable amperage control-excluding the old one I used for years, when I had to stop and crank the wheel around to change the setting. This led to a great deal of difficulty in getting good welds. I strongly recommend you never get a TIG machine without a hand or foot control. The Miller Dynasty 200 DX TIG welder I now have gives me a choice of either a hand or foot control. It merely depends upon which one I choose to plug in.
The foot control seems better when welding at a bench. The movement of your foot doesn't affect the steady movements of your hand while welding. When away from the bench, such as when I'm moving around making chassis welds, the hand control adjusts amperage for easy, slow starts and slow stops. As uncoordinated as I am, the hand control took a few minutes to get used to. However, once I did, I wondered how I ever got along without it.
There have been many advances in the TIG welding machines over the years. My Miller weighs less than 50 pounds and has electronic controls that are very handy. It will do everything my ancient 900-pound TIG machine will do, only better.
This is a TIG weld on a custom...
This is a TIG weld on a custom aluminum seat. The even bead and weld width are the mark of experience. Your first welds may not looklike this, but with some practice this is possible. The weld material must be clean and the fit good.
Benefits & Features
TIG welding is not unlike using an oxyacetylene torch. In this case, the torch is electric. The "fire" is created by the tungsten tip that creates an electric arc to the work piece. The tungsten should never touch the work piece. When it does, there will be a pfffft. Then you get to stop and grind a fresh surface on the tungsten tip. One feature that sets it apart from the torch is that the "flame" is adjustable with either the hand or the foot while the weld is in process.
With the ground wire hooked up, the argon bottle on, and a welding rod in hand, you are ready to weld. This is one area where the auto-darkening helmet is worth its weight in trophies. With it you can position your hands and just ease on the power. The light comes on and the lens goes dark. Remember, don't touch the tungsten to the work piece. The arc will start without touching. As the power comes up, watch for a molten puddle to appear. When it does, use the controller to adjust the heat. You must have enough heat to keep the puddle molten but not so much that the puddle melts through, leaving a hole in the metal.
Begin feeding the welding rod into this puddle as you move along. Too much rod too fast will cool the puddle, increase the heat, or slow down. Welding is a matter of heat control. The TIG welder works slowly and precisely. You can see what you are doing and change the heat or feed to make good welds.