MIG vs TIG
Just buy a welding machine and want to test it out? There are a number of different welding methods you can use, but the two most common processes for home projects are MIG and TIG welding. So which method do you choose for your next project?
While they may sound similar, each is distinct and often one or the other is better suited for a particular weld. The advent of low cost multi-process welding machines (welders that can do more than one process), brings the decision to the forefront for every weekend welding warrior.
Let’s take a look at what MIG and TIG welding are and how they differ from each other.
What Is MIG Welding?
A MIG (Metal Inert Gas) welder works by continually feeding a special metallic wire into your weld through the nozzle of a MIG gun. This wire acts as filler material during the fusion of the two materials being welded together. An inert gas is also supplied via the nozzle to protect the weld during the process. This gas is usually argon or a mixture of argon and CO2.
The arc created is fairly large and is typically hotter than the arc created by TIG welding and by other forms of welding. It’s also wider, which means it can’t penetrate as far as a narrower arc can.
MIG welding actually benefits from a mixed or combination shielding gas compared to a fully 100% inert gas. Pure inert gasses can reduce effectiveness of the arc, making the entire welding process more difficult and producing more spatter.
What Is TIG Welding?
With TIG (Tungsten Inert Gas) welding, a tungsten electrode is used to create an arc and fuse the metal you’re welding. An inert gas flows through the torch and over the arc in a way that’s similar to MIG welding. TIG works best with pure argon as the shielding gas.
As the metals to be joined liquify, a filler rod material is fed into the weld puddle to form the joint and bond the two pieces together. Rod is available in various diameters and materials to suit the base metals being welded. TIG welding usually requires both hands, one of which holds the torch while the other holds the filler material. Some types of joints can also be done without filler (Autogenous Welding).
Overall, TIG welding arcs are narrower than MIG arcs, so the heat is focused on a smaller space. This allows for TIG welding to penetrate farther, though it’s slower to weld. Welders are available in either dedicated process (TIG only) or multi-process.
Pros and Cons of MIG Welding
PROS
- Being a semi-automated process, it tends to be faster. Production rates or ‘weld inches’ will be considerably higher compared to TIG.
- Easier to Learn. For the beginner, the MIG process tends to be easier to pick up and easier to master.
- More welding ‘positions’ available. MIG welding also has a slight advantage with difficult to reach joints. While two hands are still recommended to steady and guide the MIG gun, single handed welds are certainly possible.
CONS
- Compared to TIG welding, there is a bit more ‘care and feeding’ required with a MIG machine. The spooling mechanism should be lubricated and cleaned per the manufacturer’s suggestions. Tips and nozzles also need to be liberally replaced to maintain a high quality arc.
- Slightly higher consumable cost. Both processes require shielding gas and filler materials but the need for additional MIG tips and nozzles required during welding give TIG a slight advantage here. Of course, accidentally dipping TIG electrodes into your weld puddle can make the costs about equal.
- More fumes and spatter. All welding produces smoke and fumes and depending on the type of wire used, MIG will produce slightly more.
Pros and Cons of TIG Welding
PROS
- Precise, high quality welds. With a narrower arc and less spatter, TIG welding is capable of producing absolutely beautiful welds.
- Wide range of materials can be welded. While MIG welding can be used on several types of materials, metals such as cobalt and copper alloys or titanium are outside its scope.
- Great for thin materials. TIG’s precise heat control is fantastic for welding thin-walled materials commonly found in the automotive and Motorsports fields.
CONS
- Slow process. This isn’t the welding method for quick + dirty joints. Stay with MIG (or even Stick welding) for that. Additional dexterity required here as well since most of the time, both hands are required.
- More skill required compared to MIG welding. There’s more variables at play when TIG welding that the welder needs to focus on over and above feeding filler rod. More hours practicing compared to MIG welding are needed to achieve the same level of proficiency.
- More joint preparation and cleaning. While both processes require prep, a good TIG joint requires that your surfaces are immaculate.
MIG or TIG - So which do you choose?
Unfortunately the answer to this question is going to be ‘It depends’. As a guide, it usually boils down to:
- What materials am I welding (type of metal and thickness)
- Are my joints going to be visible (do I care how they look)
- What’s my skill level
The size of your project also plays an important factor. MIG welding is usually the best option for large projects. Welding 100 inches on a MIG machine will definitely be faster than doing it using a TIG setup. Likewise, heavier or thicker materials are best left to MIG welding as well.
New welders may want to start out with MIG welding simply because it’s easier to learn and certainly more forgiving than TIG welding. Much of practical experience learned doing MIG can be transferred over to TIG welding too.
When the time comes for precision and nice looking joints however, TIG is the way to go. Many if not all the exposed welds we see in daily life were done via TIG. The practice required to really get good at TIG welding is well worth end results.
Our advice when choosing for your next project? Learn both methods and use the one best suited to your project. Chances are pretty good that a new welder bought today will be a multi-process model, so why not have the skills to use it.
