Gas metal arc welding, or most commonly referred to as MIG welding is a very common and sometimes preferred method of welding. Gas metal arc is personally one of the easiest and controllable welding types there is.
Gas metal arc welding was originally made for weld materials such as aluminum, copper, brass, tin and lead. It was also used on steels, but shielding gases were highly expensive in the early 1900s limiting GMAW’s use on steel. It wasn’t till the mid 1900’s for GMAW to really take off. There were many different variations of arc-length, electrode size, and power supply units. Since the MIG welder is so versatile, there are many different types of things to make this piece of equipment.
The MIG welder is simply made of five basic parts to complete the task of GMAW. No matter what on any MIG, you need to have a welding gun whether it is spooled by the machine or contains a mechanism to spool from an electrode spool mounted on it. Your welding gun consists of many parts that make GMAW possible. First off it consist of a trigger that when pulled starts the feed of electrode, gas, and initiates power to your contact tip. Your contact tip is highly conductive, usually made of copper, and is connected to the power source. Once you pull the trigger your contact tip is then contacting your electrode wire making it possible to strike an arc. The welding gun also consists of a gas hose that is ran from your machine that leads to a gas diffuser usually behind your contact tip. It then exits into a part that goes around the contact tip and diffuser known as the gas nozzle. The gas nozzle is there to evenly direct your gas into your welding area.
Next you have to have a power supply to generate voltage to make an arc. Most GMAW machines use a constant voltage instead of constant current; it helps keep arc length more consistent. Most power supplies also have a chart inside of them to set voltage and wire feed depending on material thickness and electrode size.
Electrode and Shielding Gas
Your electrode and both shielding gas can vary for different materials and highly are affected by material thickness. The electrode is there to make contact to the wielding surface and should have similar or same compositions as the metal being welded to. Your shielding gas makes a big difference when welding to, especially with aluminum and other non-ferrous metals. Shielding gases are used because most GMAW...