If you could make a welding wish list, you’d probably want a machine that could do it all. It could handle any metal, from steel to stainless to chrome-moly and even aluminum, brass and bronze. You’d be able to weld dissimilar metals — with attractive-looking weld beads — and work on wafer-thin surfaces as well as thicker metals. And you’d have precise control over the welding process so that you could create the exact bead you desired.

TIG welding can deliver all of your wishes. If you have a little patience and are willing to take the time to learn the skills and coordination required, you can master this welding process and create the metal projects of your dreams.

What is TIG?
Technically called gas tungsten arc welding (GTAW), the term TIG — tungsten inert gas — refers to a welding process that uses a nonconsumable tungsten electrode and an inert shielding gas (usually argon) that protects the welding area from atmospheric contamination. As the arc melts the base metal and creates a liquid metal puddle, filler material (in the form of a consumable rod) is added into the puddle, fusing the parts together.

Although many metals can be TIGwelded, the one most frequently associated with the process is aluminum. This material can be tricky to work with. Pure aluminum has a melting point of less than 1,200 degrees Fahrenheit,  and it’s hard to tell when it’s about to melt because it doesn’t exhibit the color changes characteristic of most metals. Further complications come from the fact that the grayish oxide or “skin” that forms on aluminum surfaces has a melting point almost three times that of the actual aluminum (3,200 F, a temperature even higher than aluminum’s boiling point).

Aluminum is an excellent conductor of heat, so it requires large heat inputs when you begin welding because a lot of the heat is lost in heating the surrounding base metal. But after welding has progressed awhile, much of this heat has moved ahead of the arc and preheated the base metal, so less welding current is required.

TIG welders are specifically designed to handle these challenges, and the type of welder you should purchase depends on two factors: the type and the thickness of metal you plan on welding. To handle the variety of jobs encountered when working on cars and around the home, select a TIG welder with good high and low amperage ranges and AC/DC output capabilities. (You need both AC and DC output if you want to weld both steel and aluminum.)

In general, a TIG welder with a range of 5 to 200 amps is ideal for working with material as light as 22-gauge (0.033-in.) steel and up to 1/4-in. aluminum. These welders are typically more expensive than MIG welders and range in price from about $1,000 to $4,000 or more for larger, professional units. In addition to the actual welder, you’ll need a bottle of argon, a gas regulator and a hose, filler rods to match the type of metal you’re welding, a TIG torch (see illustration, opposite) and a remote control. For auto- and home-related work, an air-cooled torch (where the argon shielding gas cools the torch) rated at 150 amps will be sufficient, although water-cooled torches are available for heavy-duty use.

Remote-control capabilities usually include the current (amperage) and the contactor. (The contactor keeps the torch electrically cold until it’s energized, and it starts and stops the gas flow to the torch). The most popular remote control is a foot pedal that operates much like a car’s gas pedal — the more you press it, the more amperage flows. Another type of control that affords greater mobility but is more difficult to learn is a fingertip control, which is mounted on the torch. If most of your work is done on a bench or around structures that permit mobility, a foot-pedal remote control is probably a better option because it is easier to use. However, if you plan to do a lot of work underneath an automobile or in other awkward positions, go with a fingertip control.

Making a TIG weld
While it’s relatively easy to make a strong TIG weld, it takes practice, patience and coordination to make a pretty one. You can find entire books devoted to the TIG welding process, but here are the basic steps to creating a good TIG weld:

1. Completely remove all lubricants such as oil or other hydrocarbons, and use a wire brush to scrub off the oxidation skin that forms on aluminum surfaces. Use a brush that’s dedicated to aluminum and has never been used on another type of metal.


2. Brace your arm and hold the TIG torch as you would a pencil. Pay attention to the angle of the torch and to the direction of the weld bead. In most cases, you’ll want a 15- to 20-degree angle, and you’ll use the push technique, which involves pushing the torch ahead of the weld puddle.


3. Start the arc by holding the electrode about 1/8 in. from the work surface and depressing the foot pedal (a method called a “high-frequency” start), being careful to not touch the electrode to the actual work surface.


4. Maintain consistent arc length—about one electrode diameter from the work. A common error beginning TIG welders commit is tilting the torch too much to get a better view of the electrode and weld puddle. If you need a better view, shift your position rather than that of the torch.


5. Maintain a travel speed consistent with the bead shape you desire. Moving the torch too quickly creates a bead that is too narrow, while moving the torch too slowly produces an excessively wide bead. Holding the torch too long in one spot, especially on thin metal, can result in the arc burning through the metal.


6. Once your arc is started and you’ve established a weld puddle, begin to add filler metal. Hold the filler rod at a 15- to 20-degree angle up from the workpiece, creating a 90-degree angle between the filler rod and the tungsten (see photos, opposite).

With practice, you’ll find that creating those “stacked dime” weld beads with the TIG process is more than just satisfying; it borders on the artistic. Stick with it, and you’ll soon have the basics mastered.


Special thanks to the technical departments of Lincoln Electric and Miller Electric for their guidance and assistance.