Everything on MIG / MAG welding
Is there a difference between MIG and MAG?
Yes, there is. The difference is in the type of shielding gas that's used during welding. MIG stands for Metal Inert Gas and MAG for Metal Active Gas. Argon is often used as the inert gas, or a mixture of it with helium or hydrogen. An active shielding gas can, for instance, be carbon dioxide (CO2), that's why MAG welding is also called CO2 welding. Since the way you weld will be the same no matter what gas you use however, MIG/MAG welding can be seen as 1 welding method. MIG/MAG welding can also be done without gas bottles, if you choose welding wire filled with gas.
How does it work?
A MIG/MAG welding machine supplies constant voltage, creating an electrical plasma arc between the welding wire and the workpiece. The workpiece is heated and the materials you're welding melt together. The melting welding wire is both electrode and consumable, letting you work a lot faster than for instance TIG welding. The welding wire is on a reel that you put in the welding machine and is constantly fed to the torch mechanically. You can set the speed yourself, depending on the job. That's because this affects the current you need and therefore the type of weld you want to make. The gas is necessary to protect your molten pool. If you didn't have that, the material would get way too hot and burn away.
When do you use it?
Because MIG/MAG welding is a versatile method that lets you work quickly and achieve high-quality results, it's used a lot in the (metal) industry. The welding process is suitable for mechanization, and is therefore commonly used in places where high productivity matters. Still, you don't have to work in a factory to opt for MIG/MAG welding. For instance, you can use gas-filled welding wire, without a separate gas source. Combined with a compact and portable welding machine, that makes this welding process a lot more appealing to hobby welders or DIYers looking for a machine they can easily transport.
What do you need?
For MIG/MAG welding, you'll need a welding machine that supports this welding method. In addition, you'll need shielding gas (unless you're using gas-filled welding wire) and of course a welding torch. The consumable you need for MIG/MAG welding will be on a reel. Each welding machine is suitable for a different size and weight wire reel, so that's something to keep in mind. Some welding machines have space for a wire reel with a diameter of 300 millimeters (15 kilograms) and 200 millimeters (5 kilograms). There are also smaller MIG/MAG welding machines that can take wire reels of up to 200 millimeters.
Which materials can you weld with it?
No matter which materials you want to join, the possibilities with MIG/MAG welding are endless. All kinds of steel and stainless steel of various thicknesses can be welded using this method. If you want to weld aluminum, the welding machine does need a pulse function. In that case, the current alternates between base current and peak current, letting you weld a fragile material like aluminum in a very controlled way, without burning the top layer.
What are the pros?
MIG/MAG welding is a relatively simple welding method. The welding machine usually takes care of the right settings when it comes to power and amperage, and that's an advantage for most welders. You also always have 1 hand free to support the welding torch and guide it, since the consumable is fed automatically by the torch. This makes MIG/MAG welding a quick welding process as well, letting you weld large pieces of material in short amounts of time. In addition, it can be applied in any position and the quality of the weld is high. If you choose to MAG weld with CO2, another advantage is the low price of CO2. This type of gas is a lot cheaper than argon or a flux-covered electrode.