How to Compare and Choose Between MIG and TIG Welding

In Welding

Marlin Steel on September 6, 2019

Many of Marlin's arc welding machines can perform both MIG and TIG welding as needed.For all of Marlin’s custom wire baskets, welding is crucial for ensuring that the basket is able to meet the customer’s needs. However, there’s more to welding than just heating and fusing the metal wires of the basket. There are many different specific welding techniques that can be used for a given metal form.

Using the right kind of welding technique helps ensure that a wire basket is able to hold together under stress. Using the wrong kind of welding technique, however, can lead to numerous problems, such as weaker bonds, corrosion of the weld joint, or failing to complete the weld in the first place.

Two of the most common welding technologies used in factories across the U.S. are metal inert gas (MIG) and tungsten inert gas (TIG) welding. Both of these arc welding techniques have their similarities, but there are times where one might be more useful than the other. So, how can you know when to use MIG welding or TIG welding?

Here’s a question that a lot of Marlin clients ask: What’s the difference between MIG and TIG welding?

A little confusion is perfectly normal. After all, both processes use electrical arcs to produce heat and join metallic objects. Also, both processes use an inert gas mixture to prevent corrosion of welding electrodes.

But, there are some key differences between these two electrical arc welding processes, and when to use each:

How MIG and TIG Welding Work

MIG, or metal inert gas, welding is a process that involves continuously feeding a metal wire into the weld being made. The consumable welding supply of the wire acts as a filler material to help join the two metal objects. This process is also known as GMAW (Gas Metal Arc Welding). 

TIG, or tungsten inert gas, welding uses a non-consumable tungsten electrode to run a current through the metals being joined and may or may not use a filler metal for the welding supply. Another name for this process is GTAW (Gas Tungsten Arc Welding).

Comparing MIG and TIG Welding Based on Material Thickness

Because MIG welding employs a consumable filler material to make welds, it can often complete welds of thicker metal objects in less time than a TIG weld.

Without a filler material, TIG welding needs to get the pieces of metal being welded hot enough to form a bond with each other. Typically, this is easier with thinner pieces of metal than with thicker ones. Using this process on thicker pieces of metal can create heat stress cracking and other issues.

Overall, for really thick, heavy-duty welds, MIG welding is the go-to option. For thinner pieces of metal, TIG welding tends to be the more effective solution.

MIG Vs TIG Welding: Ease of Control

To the layman, MIG and TIG welding look similar, but experts know that there are major differences in how difficult each process is.Generally speaking, MIG welding is more often recommended for ease of use. The process tends to be a bit more forgiving of mistakes than TIG welding is—so it’s often recommended for first-time operators and non-professionals.

TIG welding, on the other hand, requires very strict control over the timing, pressure, and electric current used in the weld. In most cases, TIG welding is best done using an automated, computer numerically-controlled (CNC) welding machine. Machines can reliably perform identical welds over and over much more easily than a manual welder could.

When using an automated welder (whether it’s MIG or TIG), it’s important to get the weld settings and controls just right—otherwise, you risk repeating the same mistake over and over.

Which One is Better?

The answer depends on the job in question. As noted earlier, MIG welding is typically better for heavy-duty welding work where larger, thicker pieces of metal are being joined because it uses filler material.

However, TIG welding can work wonders for joining smaller pieces of metal, such as the wires for a custom steel wire basket. Also, because the TIG process directly joins two pieces of metal, there’s no filler material to fail—meaning less money spent on welding supplies.

With robotic welding equipment, TIG welding can be a bit lower-maintenance, since the welding electrode isn’t being constantly consumed by the welding process. However, the welding electrode still needs to be properly cleaned and polished between uses—especially when welding stainless steel.

In short, choosing one welding solution as the best should be done on a case-by-case basis, which is why Marlin Steel is dedicated to having a range of tools and technologies for completing welds.

When Should You Use MIG vs. TIG Welding

So, when should you use one of these two welding techniques over the other?

A basic rule of thumb when choosing between MIG and TIG welding is to consider the following:

  1. How thick are the two pieces of metal being joined? Thicker pieces of sheet metal are very difficult to weld by simply heating them up until they fuse—the thicker they are, the more energy it takes to heat them to the melting point and the less efficient TIG welding becomes. If metals are especially thick, then MIG welding may be more effective.

  2. What is the electrical conductivity of the metal being joined? Another variable to consider is how ductile the metal being joined is. The heat used to fuse metal in an electric arc welding process is generated by the metal’s inherent electrical resistance as the electric arc tries to pass through the weld site. If metal is highly ductile, it will take more time to heat up, which consumes more energy. Electrically-resistant metal will heat up faster, making it easier to weld without filler material.

  3. Am I welding dissimilar metals? While it isn’t usually a good idea to weld dissimilar metals since it could cause numerous issues (weak bonds, weld corrosion, etc.), there are times where it may be unavoidable. If two dissimilar metals are being welded, it’s usually better to use a weld technique that supplies a filler material to create a bond. However, this filler material needs to be carefully chosen.

  4. Is surface condition/smoothness important? Filler materials increase the risk of weld spatter being left on the surface of a workpiece, requiring extra work to smooth out if the elimination of surface flaws is important. Direct metal-to-metal welds sidestep this issue to create welds that are typically much cleaner than filler-dependent ones.

If you can answer these few questions, it’s usually easy to establish which metal arc welding process would be the best for a given task. However, even when the choice seems obvious, Marlin’s engineering team still double-checks their assumptions using virtual physics simulation software to verify that the welded joint will perform as expected.

Need help developing the perfect custom wire basket for your manufacturing application? Contact the experts at Marlin Steel for a consultation.

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Author: Marlin Steel
Marlin Steel
Marlin Steel is a leading manufacturer of custom‐engineered products from steel wire and sheet metal. Its industrial material handling containers serve many industries including aerospace, defense, medical and automotive.

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