The Mig Welder
What is a MIG welder and what
is MIG welding?
Simply said, a mig welder is a "wire feeding welding
machine".
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:
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.
Mig welding machines: for DIY and trade
users
Let's start by looking at one of the smaller mig
welding machines.
The photo below shows a very basic and simple DIY or HOBBY type mig welding machine. This
sized would be ideal for light gauge welding on metal like, car panels, box trailers and general light
fabrication work.
There are four main parts to any
MIG welding machine, and they are:
1. Power supply
2. Torch or gun
3. Consumables
4. Earth clamp or ground clamp
1. Power supply
The power supply is an electrical transformer that is inside the mig welding
machine. As the name suggests its job is to transform the power. In this case it transforms it into a useable power
source that is suitable for mig welding.
Most power points at home and in industrial sheds are usually 110volt, 240volt
or 415volts.
When you plug the lead for the mig welder into the power point, the electricity
will flow into the transformer and be "transformed" into a stable and useable welding current.
2. Torch or gun
Your welding torch or mig welding gun is the most distinctive item that makes the mig welder
a mig welder.
As soon as you see the mig welding torch or mig welding gun you know that what you are
looking at is a mig welder. The welding torch is what you hang onto when you are welding. It's like a big long
black hose that comes out of the front from the mig welder.
On the end is the welding torch.There is a trigger on the torch that you press with your
fingers to start the welding process. When you press the trigger it will allow the welding wire to feed out, the
shielding gas to flow (if your welder is equipped with gas) and allow the welding current to pass as
well.
3. Consumables
Mig welding machines also use consumables. A consumable is anything that is "used up". Just
like in a printer the ink cartridges are used up and therefore they are consumables. The same is true here except
that you will consume, mig welding wire, contact tips and gas nozzles (shrouds).
Mig welding wire is a consumable. It is consumed in the welding process. The wire is
continuously fed into the welding arc and is continuously burned up. There are many different types, grades and
sizes of mig welding wire.
This particular mig welding wire shown here in this picture is a gasless mig wire. That means
you can weld with just this wire alone and do not have to use a shielding gas.
4. Welding earth clamp or ground
clamp.
The earth clamp is what is "clamped" to the work that you are welding. It is there to
complete the electrical circuit that is needed for you to be able to mig weld.
A good ground clamp will be nice and big with a very strong spring holding it closed. The
bigger and stronger the spring holding it shut, the better and more sound the earth connecting will be.
So in a nut shell, to mig weld all you have to do is plug it in, and turn on the mig welding
machine. Clamp the earth to the work. Make sure you have wire ready to go, point the gun at the metal to be welded
and pull the trigger.
You can follow these links to find out more about mig
welder duty cycle and their power
requirements.
Different types
and sizes of wedling machines.
(ie mig, mag, pulse, wire feed welder, flux cored welder etc.)
Click here to go to the mig
welding page from this mig welder page.
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