The most common welding processes used are GMAW (Gas Metal Arc Welding) also known as MIG (Metal Inert Gas) and GTAW (Gas Tungsten Arc Welding) also known as TIG (Tungsten Inert Gas). The names tell you what the electrode is essentially. MIG welding uses a consumable, metal electrode depending on what parent material you are using and TIG welding uses a non consumable tungsten electrode.
MIG welding is the easier of the two processes because there are fewer variables to control while welding. There are two settings to modify (voltage and wire feed speed) based on the material and thickness, and one trigger on the torch head to begin welding. MIG welding uses a mixed shielding gas of 25% CO2 , 75% Ar which allows the weld to get a little hotter. We want the MIG welds to get a little hotter because the electrode is consumed during welding, so the penetration of the weld is not as good as TIG welding. It’s entirely possible to MIG weld with 100% Ar gas, but the penetration will be lower.
TIG welding is a difficult process to learn because there are many variables to consider all the time as you are welding. The torch is controlled by one hand and the filler rod is controlled by the other, and the amperage is controlled with a foot pedal like an accelerator pedal in your car. Additionally, there are a variety of settings which can be adjusted, and other parameters can be varied like travel time and amount of filler added to the puddle. TIG welding typically uses 100% Ar shielding gas because the penetration of the arc into the parent material is excellent, so we don’t need any extra heat. TIG welds are also typically favoured for thin or exotic materials which are more susceptible to the effects of heat, and structural welds on dynamic systems. Some metals are best welded with Helium, but that’s a pretty special case due to the global Helium shortage, we don’t do any of that.
