Learn all about the basics of MIG welding with Blain’s Farm & Fleet.
MIG welding is also known as gas metal arc welding (GMAW) or metal active gas (MAG) welding. MIG is the most commonly used type of welding in various industries. It’s known for its speed and versatility. MIG welding is considered the easiest type of welding to learn. It can be used in metal art, farming, automotive and industrial work.
Pieces of MIG Welding Equipment
To understand how MIG welding works, we need to break down the different pieces of equipment used.
Welder and Welding Gun
Inside the welder, you’ll find a spool of welding wire. The type of welding wire you use depends on the type of metal you’re welding together. A group of rollers pushes the welding wire out to the welding gun. Both the welding wire (known as the electrode) and a shielding gas are pushed through the welding gun. The welding gun works as an anode in the welding short circuit.
When it comes to welding, there are two types of electrodes: stick electrodes and welding wire electrodes. Wire feed electrodes are used in MIG welding. The constant supply of welding wire, combined with the welding gun, make for an easy weld when compared to the other types of welding.
The shielding gas gets pushed through the welding gun. It’s used to protect the weld pool from gases in the atmosphere, such as oxygen, nitrogen and hydrogen. These outside gases can cause problems with porosity and weld spatter. The most commonly used gas in MIG welding is carbon dioxide. It can be used in its pure form, without adding inert gas. Carbon dioxide is also the cheapest gas, making it affordable for industrial work. It can be used to weld thick materials as well. Other common gases used in MIG welding are argon, helium and oxygen.
The ground clamp works as a cathode, completing the welding short circuit. It can either be clamped to the metal workbench or the piece you’re working on. The weld won’t work without a ground clamp.
How MIG Welding Works
The wire electrode is fed through the welding gun. The electrode is fed into the weld pool, where it joins the two metal materials together. The inert shielding gas is also fed through the welding gun. The gas protects the weld pool and the electrode from contamination. Because MIG welding relies on the shielding gas for protection, it isn’t typically used in outdoor welding jobs. Wind can easily disrupt the shielding gas flow, causing possible contamination of the weld pool. It also isn’t used in underwater welding.
The key to MIG welding is keeping a consistent angle and distance between the weld pool and the electrode. MIG welding is considered easier than other types of welding because you only have to hold the welding gun. In TIG welding, you have to hold a welding torch and filler wire.
If you’re welding a flat surface, the welding gun should be held at a 90 degree angle. If you’re welding a fillet weld, it should be at a 45 degree angle. Angle can vary a bit, depending on what type of shielding gas you use. Once you have the angle figured out, keep the welding gun vertical while feeding the wire.
MIG Welding Safety
Like any kind of welding, it’s important to be safe. When you’re MIG welding, always wear proper eye protection. This includes safety glasses and a welding helmet. A welding helmet protects you from arc flash. You also need to wear welding gloves and long sleeves. Proper ventilation is also important when MIG welding.