MIG vs TIG Welding – What’s the difference?

The 2 most common methods in welding (the fusing of two or more parts using heat to form a join) are MIG (Metal Inert Gas) and TIG (Tungsten Inert Gas).

MIG welding and TIG welding are both similar in terms of the operation, as both use heat generated by an electrical current to melts the base materials and/or bonding materials together. When this is cooled, it forms a solid joint to fuse the components together.

MIG Process

MIG welding uses a consumable wire electrode (or filler material) to create the weld between the component parts. It also uses a shielding gas (usually a mix of Argon and Carbon Dioxide) to protect the weld and ensure the weld penetrates the material correctly.

The electrode size and shielding gas composition is decided to suit the type of metal which is being welded The pace at with the electrode is fed is set to allow enough weld metal to create the join The wire electrode and the shielding gas are fed through the welding gun or torch When the electrode touches the metal, it creates an electrical arc to heat and melt the consumable wire rod, and a small amount of the base metal. The wire feeder continually pushes solid wire into the joint, with creates another arc – the process repeats many times per second to create the weld. When this cools, it “sets” in place to create the bond between the materials

TIG Process

The process is very similar, but the electrode used to heat the metal is fixed and non-consumable, and an external welding rod is used as the weld/filler material.

In its simplest form, it is similar to using a soldering iron, as the one hand holds the torch/gun to heat the material while the other hand dabs the metal wire into the joint.

The size of the filler material/welding rod and composition of the shield gas is calculated in the same way to suit the material being welded. The welding arc created when the rod touches the metal provides enough heat to fuse the metal together, but using the filler wire material as well creates a stronger joint Through the use of a foot pedal, the operator can tweak the amperage whilst welding to change the heat levels and to allow for precise control. When the metal cools, the filler material and base material are set in place to form the join