What MIG welding is used for - The 10 Thousand Foot View
At the highest level MIG welding is used for welding metals such as mild steel, stainless steel and Aluminum where a good looking weld is needed with little after weld clean up.
Where the finished look of the weld is important, yet you want a good weld that will hold but you don't have the time or the skills to use TIG welding.
TIG welding by someone skilled in TIG welding is by far the prettiest of welds but TIG welding takes time.
First let me give you a very quick overview of MIG welding is as it good to have some clue about the process.
MIG welding uses a MIG welder. A welding machine that feeds solid MIG welding wire from a spool - typically inside the machine.
MIG welding uses a cylinder of gas and the skills of the person welding to produce welds - the fusion of two separate pieces of metal together.
What MIG welding is Not
Now you have an idea at a high level anyway, what MIG welding is. Let me tell you some examples of what isn't MIG welding.
A welding machine that uses flux core welding wire - is doing flux core welding. That welding process does not use a cylinder of gas and is not strictly speaking MIG welding.
A welding machine that uses a stick of metal to act as the welding electrode is also not MIG welding.
Why is it called MIG Welding?
MIG welding stands for Metal Inert Gas Welding. MIG welding uses gas fed from a cylinder in the welding process. And you may also see MIG welding referred to GMAW (Gas Metal Arc Welding). The name was updated when it was discovered that Inert gasses were not the only gasses that can be used in welding.
Carbon Dioxide which is a non Inert gas can also be effectively used in MIG welding.
I have a document which explains fully what MIG welding is. Do take a look if you would like to know more on the subject.
Other Names for MIG Welding
Other names are wire feed welding. Because in MIG welding a wire - a solid metal wire - is fed continuously into the weld while you're welding.
You may also see the MIG welding process referred to as semi-automatic welding. Because the welding machine controls the electrical quality and features of the welding arc produced.
The person welding sets the cubic feet per minute they would like the shielding gas supplied at.
On the welder itself they set the speed they would like the wire fed out to the MIG gun. Lastly they set the amperage they want on the welder.
Then it is down to the skills of the person welding to control the direction they are welding in, the speed they are welding at and the position of the welding gun.
All of these components contribute to a good strong weld.
Other aspects of MIG welding to be Aware of
MIG welding is an electrical process.
The MIG welder itself uses the electricity supplied to it to generate a certain level of amperage.
The electrode - the welding wire is also known as a consumable electrode.
This is because it is melted by the welding arc and consumed into the weld providing filler metal to help make the base metals (the metals being welded) fuse and meld together.
The electrical circuit is completed when a grounding clamp - also known as the work lead - is connected to the project you are welding or to your welding table and it completes the electrical circuit back through your welder to a good ground connection in your electrical cabling.
It is worth knowing that the solid wire is matched to the base metal.
A mild steel spool of wire is used for welding mild steel, stainless steel for stainless steel, Aluminum wire for welding Aluminum base metals together.
Why is MIG Welding Good for a Beginner?
The reason that MIG welding has proved to be popular with beginner or novice welders is because with some hours practice with a MIG welder and an understanding of the process, most people can run up some good welding beads.
These beginner welds may not be the prettiest but they will hold.
Plus MIG welding machines that run on power supplies available in the home are now relatively inexpensive and with in the reach of those wishing to MIG weld.
And if you are looking for some help and direction on how to choose a MIG welder at a high level then do check out my document on that subject. It is a good primer and check list on what to look for.
The Gases Used in MIG welding
MIG welding as I mentioned earlier, uses a continuous gas supply. This gas is supplied from a gas cylinder or tank and is used to protect the weld from contaminants in the air that would cause a poor weld.
Suitable gases are;
Argon gas, for example 100% Argon gas is used for welding Aluminum.
Argon gas mixes such as C25. C25 is a 75% Argon mix with 25% Carbon Dioxide.
This is a popular mix of gas used for mild steel welding.
100% Carbon Dioxide gas is also popular because it is generally cheaper to source than C25 and is a good shielding gas for mild steel welding if the look of your weld isn't the greatest priority to you. 100% Carbon Dioxide is also used where thick metals are welded and a good penetrating weld is needed.
A Tri-Mix consisting of 90% Helium, 7.5% Argon and 2.5% Carbon Dioxide is typically used for welding stainless steel.
The Metals Welded by MIG Welding
MIG welding is most often used for welding mild steel. A common metal used around the home and in industry.
Metal Gauges that can be Welded with MIG Welding
Usually, 24 gauge to a 1/4 inch mild steel is MIG welded with a welder that can be used in the home workshop or garage, supplied with on 120 volt power.
Depending on the size of your welder, joint preparation for example beveling may be needed for welding 3/16th of an inch and 1/4 inch mild steel.
As may multiple weld passes.
If you can spend a lot more and move up to 230 volt machine Then you are starting to get within the realms of welding up to 1/2 inch thick mild steel.
MIG welding isn't used for very thin metal (a process called TIG welding is typically used there).
With skill and the right type of solid welding wire mild steel, stainless steel and Aluminum can be welded in all positions, flat, horizontal, vertical, overhead and uphill.
Though for the beginner or novice welder the flat position is the welding position normally started with.
Places MIG Welding is Used In
Due to the fact that MIG welding uses gas to protect the weld, the area used to weld in needs to be protected from the elements. Good ventilation is needed.
It is not a good idea to breathe in the fumes from a weld - known as the weld plume.
Commonly welding is done in a home garage or work shop.
And, Yes, if you have suitable transport, power and protection for your weld area you can MIG weld around the ranch, farm or yard.
What MIG welding Used for - Typical Projects
Here I want to give you an overview of the kind of projects you can look to tackle with your welding skills when you are MIG welding.
- Farm equipment repair
- Metal Gates - the building and repair
- Metal fencing - the creation of and repair
- Metal tubular frames
- Car and truck repairs
In this YouTube video, welding instructor Mark Proser walks through the steps he takes to weld a hole in a car fender. How he cleans the rust off the car part. Prepares the sheet metal to repair the fender and how he goes about welding it in.
The video is 42 minutes 37 seconds long.
Thin Gauge Sheet Metal Repair
Video Credit: Lincolnelectrictv
Continuing on with the project list.
- Motorcycle - modifications and repairs
- Bicycle repair
- Lawn Mower repairs
- Utility Trailer build and repair work
- Trailer ramps and trailer gates
This YouTube video from Red Wing Steel Works runs through the principals of starting a build of a Utility TrailerHow to Build a Utility Trailer Part 2 Cutting, Squaring and Tack Welding
Video Credit: redwingsteelworks
I have a couple of posts on the site on building a trailer
Why not take a look?
- Boat repair work
And for a bit of fun watch this 35 second YouTube video of 11 year old Caroline welding Aluminum on a yacht. She sure runs a mean bead!
Caroline MIG welding Aluminum
Video Credit: G R
Moving on with the list of projects that can be MIG welded.
- Pipe work and the repair of joints in pipes
- Artistic projects
Here is a good example of a MIG welding Art project.
A nine minute 11 second video on how to build a Gecko Lizard from a socket set. Got an old one hanging around?
Well here is a great use for it. Rooster Creations video takes you through the build of this piece. It is a fun project.
By the way I just love the music he uses for this video. I hope you do too.
Simple MIG Welding Project, Gecko Lizard from an old Sock Set
Video Credit: RoosterCreations
What MIG Welding is not Used For?
Understanding what MIG welding is used for is one half of the equation but if you are looking at getting into MIG welding it is a good idea to also understand what MIG welding isn't good at and what it isn't used for.
Here is a your starter list on what MIG welding is not used for.
1. MIG welding needs a clean stable surface, contaminated surfaces such as mill scale, rust, oil or paint needs removing before you can expect to weld and get a good strong weld without contamination.
2. Even galvanization needs to be removed before MIG welding. If you are welding with flux core wire then a galvanization coating is less of an issue. But then that isn't strictly speaking MIG welding.
3. Gappy welds. The ideal to look for when you are MIG welding is that the surfaces to be welded are close together. Large gaps, or even small gaps and uneven surfaces will cause you issues with your MIG welding. Look to tap out and level or apply a patch or cut and grind the surfaces so that they match as closely as possible before you MIG weld. Particularly if you are looking for a neat finish afterwards. The preparation work will pay dividends.
4. Welding in situations exposed to the elements. Because of the use of shielding gas from gas cylinders, MIG welding outdoors, and in moderate to high winds is not recommended. As the shielding gas crucial to protect your weld joint as you weld can be blown away causing a failed weld.
Unless precautions are taken and a shield put up to protect the welding area and gun from the wind.
5. Welding outdoors. Think through the transportation from your workshop to a weld position out in the field. Simply because care needs to be taken when transporting gas cylinders:- they are heavy, they may get dropped or damaged or leak in an enclosed area (like inside the cab of your truck) risking suffocation.
6. Great care needs to be taken when welding in wet conditions with water underfoot or in a wet place. MIG welding uses electricity. An arc is created hence the risk of electrocution. Correct insulation of yourself is important so that you do not become the accidental path to earth for the electrical arc.
7. Sparks known as spatter are inevitably produced to a greater or lesser extent depending on the skill of the person welding, the consumables used in the welder and its settings. This means welding near flammable materials or on metals that once contained flammable materials is particularly dangerous.
For example a welding repair on a car fuel tank.
Removing all flammable materials away from where you are welding is the best advice and as for a welding repair on a fuel tank - my advice is don't.
Keen to find out more about spatter? Check out my document What is Spatter in Welding and Why it Sucks.
8. Welding in tight restricted spaces. The reason for this is the shielding gasses used can displace the oxygen in the air you need to breathe.
Argon gas for example is used for the humane slaughter of chickens because it is tasteless and odorless.
If you really need to weld in a tight space, breathing gear or good ventilation must be brought in, as you really won't be able to tell there isn't enough oxygen for you to breathe until it is too late.
9. Thin metals, depending on your skill, less than 24 gauge is not recommended for MIG welding. This is due to MIG welding being a 'hot' process and the burn through of thin metals happens. Ruining your weld.
10. Cast Iron, Copper, Brass and other exotic metals such as Magnesium, Titanium are not considered suitable metals to MIG weld. There are other processes used for welding these materials.
I hope you enjoyed my article "What is MIG welding used for? Have an idea in 10 minutes" and I hope I have answered your questions.
And if you would like to find out more detail on what makes a MIG Welder a MIG welding machine do take a look at my article "What is a MIG welder, a Guide for Extraordinary People." - Link