Learn How To Weld

The Mig Welder

What is a MIG welder and what is MIG welding?

Simply said, a mig welder is a "wire feeding welding machine".mig welder WIA weldmatic 255s with wire traveller

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:

  • Metal Inert Gas
  • Metal In Gas
  • GMAW - Gas Metal Arc Welding
  • MAG - Metal Active Gas
  • Gasless mig welder
  • Gas mig welder
  • 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". If a wire is being used but you are not using any shielding gas this is gasless mig welding.

MIG welding or metal inert gas as it is called today uses an inert gas. An inert gas is a welding gas that does not have any added reaction to the mig welding process. This gas is usually Argon (Ar).

MAG welding is when you use an active gas. The active gas is always Carbon Dioxide which is Co2. It will react with the welding arc and assist with the welding.

It also means "Metal In Gas" as there is metal in the 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.

There also seems to be a cultural language difference in the terminologies of a mig welder and wire feed welder between the United States of America, and where I'm from in Australia.

It seems that if you are doing any kind of flux cored welding the yanks tend to call it a wire feed welder or a flux cored welder. They s eem to see it as different welding machine. Over here in Australia, we all refer to it as just a "mig welder". Regardless if someone is using flux cored wire with gas, or is using a gasless mig wire that does not need gas, we just call it a mig welder.

Another note: We in Australia wear thongs on our feet, the yanks wear them up there bum cracks, lol.

Just something I have noticed!

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.

A MIG welder can be broken up into three main things.

 

The 3 most important parts of a mig welder

  • Power supply
  • Mig welding gun
  • Mig welding wire

These are the three main items to discuss when considering buying a mig welder.

 

 

See mig welding machines