Last Updated on May 13, 2020
There are many different forms of welding to choose from, but two of the most popular are TIG and MIG welding. Just by the name, they seem like they must be pretty similar, right? In reality, they’re very different processes, although they both do similar jobs. Sometimes they’re interchangeable, but the processes of each are quite different, and so is the skill required to perform them. You’ll also need different machinery, and the results can vary between processes. In this article, we’re going to break down the differences between MIG and TIG welding, and we’ll even discuss when you might prefer one to the other.
MIG welding has become very popular in recent years. There are several reasons for this, but two of the main reasons are the lower cost of machinery and the lower level of skill needed to produce MIG welds over other types of welding.
MIG stands for Metal Inert Gas welding, but you may also see it called Gas Metal Arc Welding or GMAW. It’s a wire-fed type of welding where you pull the trigger on the gun and a thin metal wire extends from the tip. The wire is both the electrode and the filler metal. Electricity is sent through the wire and creates an arc from the wire to the metal being welded. This arc heats the wire, melting it into the joint and turning it into a filler metal. A gas, usually a blend of argon and carbon dioxide, is used to shield the weld from contamination.
MIG welding has some notable advantages over TIG welding. It’s much less complicated, so there’s a shorter learning curve. There are fewer variables to consider, and the process is generally considered to be easier. Also, MIG welds can penetrate through paint, mill-scale, and even rust/corrosion, so you don’t need to spend hours prepping your metals ahead of time.
On the other hand, MIG welding has some drawbacks that are also worth mentioning. Compared to TIG welding, you get less control over the puddle, which results in a more raised weld that’s just not quite as pretty as a well-done TIG weld. You also can’t weld as thin of materials with a MIG welder, so the finest welds will need to be performed on a TIG machine.
TIG stands for Tungsten Inert Gas welding, and it’s also called Gas Tungsten Arc Welding, or GTAW. In TIG welding, the electrode is non-consumable, and it’s a small metal tip that protrudes from the gun. Electricity forms an arc between the electrode tip and the metal that’s being welded. This arc is high enough temperature to melt the metal and create a weld. This gives TIG welding the advantage of not needing a filler metal. This is especially useful when welding very thin metals. But you can use a filler metal if wanted, though you’ll have to operate it with your other hand.
TIG welding is a slower process than MIG welding, and it’s made even slower by the large amount of prep work that’s necessary. TIG welders can’t make a proper arc if there isn’t great contact with the base metal, so you’ll be spending a lot more time cleaning up the metals you plan to weld.
While performing a TIG weld, you’ll use a foot pedal to control the amperage. If you’re also using a filler metal, this means you’re using both hands and a foot to create the weld. Compared to the simple trigger pull of a MIG welder, this is a much more complicated process that takes longer to learn and perfect. However, it also offers you greater control over filler speed and amperage, so you get better control of the entire weld. This results in flatter, nicer-looking welds than what you can achieve with a MIG welder.
So, which one do you need? It depends on your goals. Each type of welding has particular scenarios where it reigns king. In a perfect world, you’d have both machines at your disposal. But even then, you’d have to determine when to pick each machine for any specific task. Let’s take a look at some common times you’d pick either machine.
Some welds aren’t going to be seen, such as those on the exhaust underneath a car. On the other hand, some welds are going to be completely visible, so they must look as good as possible. For these situations, a TIG welder is going to be your best bet. Since you get so much more control over the bead when welding TIG, you’ll be able to produce a flatter, cleaner weld that looks much prettier.
Sometimes you have to weld metals that have corrosion, paint, and dirt on them. For a TIG welder, this could present a serious problem. But a MIG welder won’t have much difficulty with these metals. MIG welders can easily penetrate through paint, dirt, rust, corrosion, and more, so you don’t need a perfectly clean surface to weld. TIG welders need contact with the bare metal for the electricity to conduct and form the arc, so they’re not optimal for welding dirtier base metals.
Sometimes you just want to join two pieces of metal together without adding a filler. In this case, the only option is TIG. MIG welding requires filler metal since it doubles as the electrode. With TIG welding, you can just use the heat from the arc to melt the two metals together, forming a strong bond with no filler material.
For welding the thinnest metals together, TIG is the most preferable process. You get more control with TIG welding, so you’re less likely to punch through the thinner materials. Plus, you can opt to perform the weld with no filler metal, which may be preferable when using such thin workpieces.
For those just starting with welding, MIG welders offer a much easier way to get into the process and start creating welds. There is a lot less to consider and the equipment is also generally more affordable. MIG welding is considered to be much easier since you only have to think about one hand pulling the trigger and performing the weld. With TIG, you’ll be using both hands and a foot to control the bead. MIG welding also needs less surface prep to get a good bond, so you’ll have fewer frustrating experiences while learning to weld with MIG.
While MIG and TIG may only be a single letter apart in name, they’re worlds apart in function. Neither is necessarily better, but they have a lot of differences that can make either preferable in certain situations. MIG welding is easier to perform, works on dirtier base metals, and is cheaper to get started with. But TIG welding gives you more control, can weld thinner metals, can be done with or without filler metals, and makes flatter and better-looking welds overall. If you can’t decide between these two useful forms of welding, then you may just decide to get a multi-function welder that offers both!
Hi there! My name is Adam and I write for HealthyHandyman. I have a great passion for writing about everything related to tools, home improvement, and DIY. In my spare time, I'm either fishing, playing the guitar, or spending quality time with my beloved wife. You'll also often find me in my workshop working on some new project!