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Choosing the right polarity is part of the process of setting up a TIG welding machine for best effect, and is made fairly simple by the straightforward controls found on most of these welding implements today. Like all arc welding, TIG welding is accomplished by making a complete circuit through the welding gun, the workpiece, and back to the welding machine itself again. This is achieved by attaching a welding clamp to the metal as close as possible to the actual welding site.

Since the electrode used by a TIG welding machine is not a consumable filler metal wire, it needs much different treatment than that used in MIG welding. The electrode in MIG welding is continuously fed into the welding pool, melting in the electrical arc that it is generating, and so your main concerns are to ensure that there is enough wire and that it continues to move properly through the rollers to be delivered to the welding site.

Amperage and voltage are just as important in TIG welding as in any other type, though, as you might expect, they are used in slightly different ways. TIG welding is never carried out with the tungsten electrode in direct contact with the base metal; there is always at least some gap between the electrode and the substrate. Most of the heat is generated by the resistance of the air rather than that of the metal, which is part of the reason why TIG welding heat is concentrated in the joint and is less apt to warp nearby metal.

The finished weld provided by MIG and TIG welding techniques is very different, as might be expected from such highly divergent welding processes. The weld that a MIG welder produces is tough, but stiff and hard, while a TIG weld tends to be more flexible. This is not to say that it is weaker than a MIG weld – far from it, TIG welds can be very strong and, with some materials, can be stronger than their MIG counterparts, as for example in the case of aluminum.

If you have ever welded using a MIG welding machine and a flux-coated or flux-cored filler wire, then will know that this procedure makes clouds of smoke that can obscure the welding pool from view, or even occasionally hide it totally. Needless to say, this can be quite a problem if the angle you are welding at forces you to look through this cloud of smoke most of the time, and can seriously affect the accuracy and quality of your weld.

One of the most pleasant aspects of biological science is that once a living creature has been officially named, it retains the same identical name forever. This allows us to identify exactly what creature the creator of the scientific naming process, Linnaeus, was writing about two centuries ago, for example, despite the numerous cultural changes since then. Welding, unfortunately, has not caught up with this excellent system, and names are subject to change at the whim of a handful of ivory tower experts at more or less any time.

TIG welding – named for the tungsten inert gas description which originally applied to it – is a very different beast, so to speak, from MIG welding, with entirely different characteristics, challenges, and equipment settings to produce the best possible results. The setup of a TIG welder is a bit simpler than that of its MIG counterpart, but the actual use is more complex. However, there are many advantages to TIG welding, too. It is the method which produces the world's finest welds – handcrafted masterpieces that cannot be rivaled by any other welding technique.

One of the more difficult welds to make is a fillet weld – one which runs along the boundary between two pieces of metal being fastened together at right angles. One piece of metal is mounted edge-on to the flat surface of another piece of metal in a tee joint, whereas if the metal pieces are joined at the edges, but with a right angled position rather than a flat position, this is a corner joint, not a tee joint.

Although this will take some practice to master, your MIG welding will be most successful if you learn how to change voltage and amperage according to the needs of the moment, and of the weld that you are making. The depth, width, and shape of the weld will vary as you change these two electrical characteristics of your welding machine, and as you will discover, different metals, angles, and projects all have an optimal width and shape of weld to produce the strongest bond possible.

    The gas which wreathes your welding pool, blown from the diffuser contained within your MIG welding gun, is almost as vital to the quality of your weld as is the filler metal or the method of deposition – and perhaps more so in some circumstances. If you are using a FCAW (flux core arc welding) process, then obviously you need not be concerned with shielding gas. The gas is provided by the vaporizing core of flux, which is already chemically matched to the type of wire that is surrounding it for optimal performance.