Definition
An electric arc welding process in which a continuously fed solid wire electrode is melted to join metal parts, while a shielding gas (such as argon, helium, or carbon dioxide, or a mixture) flows from the welding gun to protect the molten weld pool from contamination by the surrounding air. Commonly known by its older name, MIG (metal inert gas) welding.
Plain English
A welding method that uses a thin metal wire fed through a gun. Electricity melts the wire, joining the parts together, while gas blown out of the gun keeps air away from the hot metal so the weld stays clean.
Context Anchor
Seen in aircraft maintenance and repair discussions involving approved welding methods for metal parts.
Derivation
The name describes the process literally: a gas shields the weld, a metal wire serves as the electrode, and an electric arc supplies the heat. Older texts call it MIG welding; the FAA and AWS now prefer GMAW because not all shielding gases used today are inert.
Why Pilots Care
Many aircraft structural components — engine mounts, landing gear parts, steel tube fuselages — are welded. Knowing the welding method used affects repair approval, technique selection, and inspection of completed work.
Intuition Check
The gas in gas metal arc welding is not the fuel that makes the heat. The electric arc makes the heat; the gas shields the hot metal from contamination.
Example Sentence 1
The mechanic used gas metal arc welding to repair a crack in the steel tube fuselage.
Example Sentence 2
Proper shielding gas flow during GMA welding prevents porosity that could weaken the airframe structure.