TIG Welding Machines

The fine hand work of a skilled artisan is something that is appreciated in many different fields, but people seldom realize that certain types of welding and welding machines are designed specifically to be used by skilled welders to produce welds of extremely high quality. Images of robotic welders assembling cars in Japan have become such a commonplace of the world’s mental landscape that the human factor is often lost sight of in the welding industry, at least in the eyes of the general public. However, TIG welding machines are used manually for high-quality hand welding, and can handle some of the most complicated joints and toughest applications in metal fabrication.

TIG welding is slower and more costly than other types of welding that can be fully automated, or handled by barely-trained welding operators, but it compensates for this with the excellence of its results. High-pressure applications such as welding on boilers and aircraft parts is often handled with TIG welding machines, and indeed, the first TIG devices were developed around the time of World War II for aircraft construction.

A TIG welder is a “Tungsten Inert Gas” welder that features a permanent tungsten electrode for arc welding, uses an inert or semi-inert gas such as argon or a mixture of argon and helium to shield the welding site from oxygen to prevent oxidation of the weld, and, when necessary, uses a separate feed of filler metal as the ‘solder’ for the welding process. TIG welding machines require a skilled user, and a closer look at some TIG welding techniques reveals more about the operation of these extremely flexible machines.

TIG welding techniques

When a person is making a weld with a TIG welding machine, there are several different options for the welding technique to be employed. The three methods available to the welder are the push technique, the pull technique, and the perpendicular technique. Each is defined by the position of the welding gun and electrode relative to the point of welding and the welding pool (which is the pool of liquid metal present at the exact point where the welding is taking place). The push method is the most frequently used, although all have applications depending on the type of metal being welded, the thickness of the pieces, and so on.

The push method involves holding the welding gun and electrode behind the welding point, slanting forward past the end of the already welded area. Holding the welding gun in this fashion gives the welder excellent visibility to the point where they are welding, and has several other advantages as well. The shielding gas blown from the nozzle covers the area of the joint before the heat is even applied, meaning that the welding pool is always covered completely by shielding gas and accidental corrosion or oxidation is practically nonexistent. The push method results in a wide, shallow-penetration weld that is good for thinner metal types. The weld is also very low-lying and smooth.

The pull method positions the welding gun ahead of the welding point, slanting back towards it, and moves away, ‘pulling’ the weld along with it. This method does not protect the welding pool from the atmosphere as well and may result in light contamination of the weld (or at least soot on its surface). The pull method produces narrow, deep-penetration welds, suitable for workpieces made out of thick metal and joints that need a very strong weld. The perpendicular method witnesses the welding gun held at right angles to the workpiece, pointing directly at the welding pool, and has effects midway between those of the push and pull methods.

These three methods are the basic building blocks from which the versatile applications of TIG welding are derived. The welder can choose the technique best suited to the needs of the job, the thickness of the metal, and the depth of weld needed, and adjust the results simply by the orientation of their welding gun.