MIG welding is a process that uses a continuous wire feed to join metals. It’s one of the most popular welding methods because it’s relatively easy to learn and produces high-quality welds.
Advantages of MIG welding are:
- Weld Speed
- Weld Quality
- Long-Pass Welding
- Fewer Stops and Starts
- Higher productivity
- Deep penetration on various materials
- Clean process
- No Stub end losses
In this article, we will take a closer look at some of the advantages and disadvantages of MIG welding.
The Advantages of MIG Welding
Let’s start with the good stuff first and describe the advantages of MIG welding.
MIG welding is one of the most versatile welding methods, as it can be done semi-automatically or fully automatically and on a variety of materials such as steel, stainless steel, cast iron, magnesium, and aluminum.
2. Weld Speed
If you compare MIG to other welding processes, it’s going to be faster most of the time even with beginners welding. The answer to this hides behind continuous feed wire and pulse-on-pulse technology.
The electrode is supplied to the weld through a welding machine or a spool-gun MIG torch which makes MIG one of the easiest and fastest welding processes to learn and use.
The ease of operation and automated operations of the MIG torch, combined with the small learning curve, makes MIG one of the first welding processes that beginners learn. These factors allow them to focus on learning how to weld and not having to deal with the complexities of welding equipment.
If you haven’t welded before, you can learn MIG welding in as little as a few hours, This how easy it is. Some instructors online claim to be able to provide basic training in as little as half an hour, where the majority of teaching is spent on cleaning the weld.
4. Weld Quality
Due to great weld pool visibility and welding simplicity, you will be able to achieve consistent and great-looking weld results.
This makes MIG one of the most popular welding methods used in the industry because it can be very predictable.
NOTE: Because MIG is flux-free, there's no risk of slag entanglement in the weld.
5. Long-Pass Welding
When you need to achieve long welds with superior strength and cosmetic appearance, a fast welding process like MIG is your go-to choice. Because of continuous wire feed, you will be able to deposit more weld material faster than with any other process.
6. Fewer Stops and Starts
The continuous wire feed of MIG welding makes it possible to weld continuously without stopping or starting as is the case with other welding processes such as stick welding.
7. Higher Productivity
Given all the factors mentioned above such as speed, long-pass welds, and fewer stops, MIG welding is generally more productive than stick or TIG welding.
It’s common to see higher productivity in applications such as machine and equipment manufacturing, piping and vessels fabrication, and steel construction.
8. Deep penetration on various materials
MIG welding can produce welds on a variety of materials including aluminum, stainless steel, and magnesium with the right amperage settings.
9. Clean process
Because MIG uses a shielding gas to protect the arc, there’s no flux that will contaminate the weld, making MIG welding a cleaner process than other welding methods such as stick welding.
After simple cleanup, you can focus on the new welding task and not worry about slag removal which is needed with stick welding.
10. No stub end losses
When stick welding, a small amount of electrode wire is wasted at the start and finish of each weld. This stub end loss can be as high as 1/3 of the electrode wire consumed.
Thus, substantial savings are realized when welding with MIG since no stub end losses occur and wasted time replacing them is kept to a minimum.
The Disadvantages of MIG Welding
Even though there are a number of advantages to using MIG for your welding projects, it also has a few disadvantages that you should be aware of.
1. Set up cost is higher
High-quality MIG welding machines cost more compared to other types of welding equipment. In addition, with most higher-end MIG welding machines, you can perform additional functions such as tungsten inert gas (TIG) welding, stick welding, and even plasma cutting.
TIP: When buying a MIG welding machine, check if it allows component-level repairs. This way, when something brokes in the future, you can replace/fix only that part.
2. Burn-Throughs and Undercutting
MIG welding machines use a constant voltage output, which makes them susceptible to burn-throughs and undercutting.
Burn-through is the penetration of the material’s surface during thin materials welding. Undercutting occurs when tungsten is not properly shielded from the purge gas, resulting in an unmelted electrode.
Undercuts are usually seen on the underside of the material, but they could potentially occur on both sides.
3. Hot Spots and Distortion
Since MIG uses a constant voltage output, there is no fluctuation in output which can lead to hot spots on your welds. This can result in warping, distortion, and even cracking of the welding puddle.
4. Not best for a windy environment
MIG welding requires a constant gas flow to produce a smooth and consistent weld. Wind, rain, and other adverse weather conditions can interfere with the gas flow and affect your MIG welding results. In this situation, you should opt for flux-cored arc welding (FCAW) or stick welding.
5. Frequent gas changing required
Since MIG uses a continuous wire feed, you will need to change the shielding gas frequently while welding to avoid contamination of the weld pool. This is also one of the reasons why MIG equipment costs more.
6. Limited Positions
Vertical or overhead welding is not possible due to the fluidity of the welding puddle and the high heat input of a MIG welder.
If your welding doesn’t require any of the above positions, this is probably not that big a deal for you.
7. More Maintenance Required
The MIG welding machine is more complex compared to others such as stick welder so you will need to perform some routine maintenance tasks.
This includes cleaning the gun, checking the wire spool, changing the gas, replacing contact tips and nozzles, and making sure that your MIG machine operates at optimum conditions.
8. Fast Cooling of Weld Pool
Since welds are clean and not covered in slag, they cool fast during welding, resulting in thicker and wider weld beads.
This means that you will need to increase the wire feed speed, which also results in excessive spatter, a leading cause of weld contamination.
9. Not appropriate for Thick Metals
While MIG welding is suitable for thin materials, it cannot be used on thicker metals because of the high heat input.
If you need to weld thick metals, you should consider other options such as FCAW, submerged arc welding (SAW), or GTAW.
TIG welding is considered to be more difficult because you need to learn not only the machine but also understand Tungsten inert gas (TIG).
If your projects are mostly on small scale, then MIG welding is perfect for you. However, if you plan to do large-scale welding projects, it is advisable to start with stick welding.
Stick-out is an unmelted wire coming out of the welding gun. It happens due to the wrong amperage and wire speed settings.