Tig Welding Process. The MIG weld process, or Metal Inert Gas weld, fuses the metal by heating with an arc. With this type of weld, the arc is placed between the filler metal electrode and the work piece. Shielding is provided by outwardly supplied gas or gas mixtures. A TIG weld or Tungsten Inert Gas, on the other hand, functions by joining metals through the process of heating with tungsten electrodes that do not become part of the completed weld. The process utilizes argon or other inert gas mixtures as shielding and filler metals are rarely used. Regardless of whether you are using a cheap tig welder, the process remains the same. Tig welding is an art, and every day, more and more become certified users.