What is the primary difference between MIG and TIG welding?

• A. MIG welding automatically feeds the filler wire into the weld pool; TIG welding uses a tungsten electrode to conduct electricity and provide the heat source, and the filler wire is fed manually into the molten pool
• B. MIG welding uses a tungsten electrode and manual filler wire feed; TIG welding uses a filler wire automatically
• C. MIG welding does not require shielding gas; TIG welding requires shielding gas
• D. MIG welding is always faster than TIG welding

Answer: (A)

The main idea here is how each process provides filler metal and what kind of electrode creates the arc. MIG welding uses a consumable filler wire that is automatically fed through the gun, so the wire itself supplies the filler metal as you weld. TIG welding uses a non‑consumable tungsten electrode to generate the arc, and any filler metal is added separately with a filler rod by the welder, fed manually into the molten pool. Shielding gas is used in both methods, but the critical difference is automatic filler wire feed with a consumable electrode versus manual filler with a non‑consumable electrode. This distinction also helps explain practical differences: MIG is generally faster for many production tasks, while TIG offers higher control and cleaner welds on thin materials.