The Mig Welder: One of the best tools in the shed
What is a MIG welder and what is MIG welding?
Simply said, a mig welder is a "wire feeding welding machine". See: Mig welding machines
Wire feeding meaning that wire is continuously feeding into the welding process. They are the most common and widely use welding machines in the world.
From DIY to the welding and fabrication shops in town, the Toyota's, Mitsubishi's and Caterpillar's, ......everyone uses them. They are the most cost effective, productive and easiest way of welding.
When we say MIG welder, this is also what we mean:
1. Metal Inert Gas
2. Metal In Gas
3. GMAW - Gas Metal Arc Welding
4. MAG - Metal Active Gas
5. Gasless mig welder
6. Gas mig welder
7. Wire feed welder
These are all the terminologies that fall under the abbreviated "MIG".
During the welding process a gas is used to shield the weld puddle. This is the "Inert Gas" or the "Active Gas".
Originally in the early days MIG meant "Metal Inert Gas". Being that the inert gas, "is a gas that does not react with the substances coming in contact with it". The gas is used to shield the welding arc from oxygen and other natural gases in the air we breathe so that the welding process is done successfully.
Now days the term MIG is referred to as "Metal in Gas". As there are a variety of different gases that you can use in the welding process.
Not all of these gases are inert.
Some gases are designed to react with the welding process to make is successful. This is now an active gas as opposed an inert gas, so we can also call it "MAG - Metal Active Gas".
The general term that we use though is "Metal in Gas".
Some people might say they have a "gas MIG welder", which is what we were talking about. Or they might say they have a "gasless MIG welder". Meaning that it is still a wire feeding MIG welder, but does not need the shielding gas to operate.
These "gasless" MIG welders are usually used by the home fabricator or when there is lots of welding to do outside in the wind on a farm, or for on site jobs.
For the home fabricator the cost of purchasing or hiring a bottle or gas may be too much to be justified for the occasional welding job.
For the fabricator working outside in the elements, there is no need to worry about wind blowing the shielding gas away from the welding arc.
How does a mig welder work?
A mig welder runs off electricity and uses the electrical current to raise the temperature of the base metal and fuse the filler metal (MIG wire) together in an electrical arc.
This is your welding process.
The electrical current is passed from the power point on the wall, into the welding power supply, through the welding torch.
When the trigger is squeezed the current then travels through the contact tip onto the wire making the welding wire live and conductive.
On the part you want weld, you attatch the "welding earth" lead. Then when the MIG wire touches the earthed part, the electrical circuit is complete. As a result, the electricity starts to flow making a flash of sparks and an arc is created.
This arc is welding, without it you have nothing. Rememmber that "arc welding" is the process of welding using electricity. Mig welding is still arc welding as it uses electricity to make an arc, it's just that we call it MIG welding.
The 3 most important parts of a mig welder
A MIG welder can be broken up into three main things.
Power supply
Mig welding gun Mig welding wireThese are the three main items to discuss when considering buying a mig welder.