Arc welding (MIG, TIG, MMA) is a method, which produces electric arc between an electrode and the workpiece. Electric power supply is used to produce electric energy.

Arc welders melt the metal (workpiece) at the welding point. In most cases consumable filler rod is used as the deposit. At the welding puddle oxygen or nitrogen can cause imperfections. Therefore, a shielding gas is added to protect the weld.

This process is generally used for:

• MIG (metal inert gas) or GMAW (gas metal arc welding) welders
• TIG (tungsten inert gas) or GTAW (gas tungsten arc welding) welders
• MMA or stick welders

MIG (GMAW) and TIG (GTAW) welders are standard in welding and fabrication industry. These welders are robust, efficient and require low cost.

Metal Inert Gas (MIG) Welding or Gas Metal Arc Welding (GMAW)

Gas Metal Arc Welding is a consumable electrode method. It uses a filler wire as the electrode and deposit. MIG or GTAW is a very simple and well-automated process. MIG welder requires only one hand to run the torch or gun (though 2 hands are advised for stability). Metal Inert Gas or Gas Metal Arc Welding was designed to weld aluminium and other non-ferrous materials.

However, MIG welders are now capable to weld steel. Power supply usually applies constant voltage and DC current. However, other variations are also used. MIG welders are known to be value for money.

Any GMAW welder below $500 dollars is considered of little industrial value. GMAW welders produce great welds but they are not easy to trouble shoot. They also require setup (filler wire) as an expense for automation.

MIG Welder (GMAW) Summary

• MIG welder uses consumable electrode
• MIG welder is simple to learn
• MIG welds aluminium, non-ferrous materials and even stainless steel
• MIG welders are expensive
• MIG welds are neat but difficult to troubleshoot

Tungsten Inert Gas (TIG) or Gas Tungsten Arc Welding (GTAW)

Tungsten inert gas (TIG) or Gas tungsten Arc Welding (GTAW) use nonconsumable electrode. TIG welders usually use filler rod as a weld deposit. In some cases TIG welder uses heat to produce joints. This is called autogenous system

TIG / GTAW can weld almost all materials. It is most often used for stainless steel and light metals. TIG welders are the most difficult to master. However, they are preferred welding choice for precision engineering industry. TIG / GTAW applications are endless. The aerospace industry is almost exclusively using this welding method.

TIG Welder (GTAW) Summary

• TIG welder uses non-consumable electrode
• TIG welder is difficult to learn or troubleshoot
• TIG welds almost all materials
• TIG is preferred in precision welding and fabrication industry

Arc Welding: MMA or SMAW or stick welding

Other than MIG or TIG arc welding technique is a shielded metal arc welding (SMAW). It is also known as manual metal arc welding (MMA) or stick welding. The process uses consumable electrode (stick) which is compatible with workpiece. The electrode is also covered with flux to protect against oxidation.

The MMA process is inexpensive, simple to learn but very slow. It has applications in small welding industry. However, MMA / SMAW will not be described further on. The reader is referred to welding manuals and documentation to obtain the knowledge.

MMA or Stick Welder (SMAW) Summary

• MMA / Stick welder uses consumable electrode
• MMA welder is simple to learn
• MMA welds generally ferrous materials
• MMA / SMAW welders are cheaper then MIG or TIG welders
• MMA / SMAW welding is slower than MIG or TIG welding