Definition
An electric arc welding process in which a continuously fed bare metal wire serves as both the electrode and the filler material, while an inert shielding gas (typically argon, helium, or a mixture) flows from the welding gun to protect the molten weld pool from atmospheric contamination. Now more formally known as Gas Metal Arc Welding (GMAW).
Plain English
A welding method where a machine continuously feeds a thin metal wire through a handheld gun. An electric arc between the wire and the metal melts them together, while a stream of protective gas blown out around the wire keeps the hot weld clean.
Context Anchor
Seen in aircraft maintenance discussions about welded repairs, fabrication, and approved welding procedures for metal parts.
Derivation
The name comes from the two key features of the process: the Metal wire electrode (rather than a non-consumable tungsten electrode) and the Inert shielding Gas. Knowing this makes the abbreviation self-explanatory once you see one of these welders in operation.
Why Pilots Care
Maintenance technicians need to know which welding process is appropriate for a given aircraft repair. MIG welding is faster and easier to learn than TIG welding but produces less precise welds, so it is generally used on heavier steel structures rather than thin aircraft skins or critical thin-wall tubing.
Intuition Check
MIG welding does not mean any welding done with a wire spool. In aviation maintenance, the material, shielding gas, settings, and approved repair procedure all matter.
Example Sentence 1
The technician used MIG welding to fabricate a new steel engine mount bracket from heavy-gauge tubing.
Example Sentence 2
MIG welding produces smooth, strong joints suitable for restoring damaged aircraft brackets and fittings.