Many kinds of metals out there may be welded to create a strong bond but there are exceptions to this rule. For example, steel and aluminum cannot be welded together because they have different melting points. As steel takes roughly twice the temperature of aluminum to weld, the aluminum becomes a liquid and will not stay near the steel. But beyond this, when steel and aluminum fuse together they form a fragile bond that is not really effective.

This type of welding is known by several common names—TIG Welding, Heliarc Welding and Gas Tungsten Arc Welding. Unlike the other types of welding mentioned so far, this type does not use a consumable electrode. Instead, the welder uses an external rod to create the molten metal needed to forge the weld. TIG welding is known for its strong, high-quality welds, though it does require a higher level of skill than other types of welding. The welds made from TIG welding also tend to be very clean and attractive to the eye. Gas Tungsten Arc Welding does require an inert gas shield which, for this type of welding, is usually argon or an argon mixture.

Shielded metal arc welding, frequently referred to as stick welding, is a very common and popular method of welding. It is typically used in construction, steel fabrication, pipeline work and for repairing heavy equipment. It is a type of arc welding, in which a lightning-bolt-like electric current runs between the electrode, or “welding rod” (the part you hold in your hand) and the substrate (the metal you are welding). When stick welding, the welder uses a consumable electrode; that is, the welding rod itself melts, creating the weld. The electrodes have a flux core, which is a chemical cleaner. As the metal in the electrode melts, the flux prevents oxidation which can weaken the weld.

This type of welding—also called MIG (Metal Inert Gas) Welding—also uses a consumable electrode. However, in MIG welding, the electrode is a solid wire that is constantly fed through the welding gun. MIG welding machines are designed to accommodate varying sizes and gauges of these welding wires. Instead of using flux to prevent oxidation and other metal-weakening agents, MIG welders use an inert gas, which is also run through the welding gun. This gas could be carbon dioxide, or a mix of carbon dioxide and argon. MIG welding may also result in fewer fumes than stick welding. This type of welding is easy to learn and can be used on a wide range of metals. With the availability of portable MIG welders, Gas Metal Arc Welding has become much easier to bring to the location of the work needed.