TIG vs MIG welding

TIG vs MIG welding

TIG vs MIG Welding

In this article, we’ll take a look at the often asked TIG vs MIG welding question of “which is better, TIG or MIG welding”?

In truth, the answer is simply “it depends”.

There are times TIG is preferable and other times MIG is.  In the cases where either will do the job, it’ll come down to the welder and the tools that are available.

With this in mind, we’ll take a look at the TIG vs MIG welding question not with a mind of which is better, but more to explore how they are different and, in the end, when one may be preferable over the other.

What is the difference between MIG and TIG welding?

We should start with a basic explanation.  Tungsten Inert Gas (TIG) and Metal Inert Gas (MIG) are welding techniques that have as many similarities as differences.

Both are meant to join separate metallic objects together and both use an inert gas mixture as a means of preventing or reducing the corrosion of the welding electrodes.

MIG welding defined

TIG vs MIG welding

MIG welding is arguably one of the easier techniques to learn.  It is often referred to as the “hot glue gun” method of welding and the similarities between a hot glue gun are obvious.

MIG welding feeds a consumable electrode through the spool gun at a preconfigured speed.  The flow of electricity through the electrode and the metal causes the electrode to melt, creating a pool of molten weld.

As the welder pushes traverses the length of the metal to be welded, the weld pool is continuously created, leaving in it’s wake a (hopefully) beautiful and symmetric weld bead.  Sometimes, they aren’t so beautiful.

MIG uses the filler material to bond the surfaces being welded so is able to weld different types of metal together.  This also makes MIG the technique of choice for welding thicker metals as the metal to be welded does not have to heat up as much.

What is MIG welding used for

MIG welding excels and is seen often in automotive and construction arenas.  MIG can provide strong welds for very thin materials which works well for vehicle bodies and parts.

MIG works well with steel, stainless steel and aluminum.

Construction – MIG welds abound in the steel structures of the buildings we see every day.  For structural steel work, MIG has become the welding method of choice.

Manufacturing – for products that are produced in mass quantities, MIG is often chosen due to it’s ability to cost effectively and quickly get the job done.

TIG welding defined

TIG vs MIG welding

TIG is a bit more complex and requires more dexterity than MIG welding as you’ll need to use both hands and a foot.  The process is a bit slower than MIG but the resulting welds are cleaner and there is no weld splatter to contend with.

As with MIG, the flow of electricity through the gun, the electrode, and the metal surfaces to be welded heats the welding material and causes a pool of molten metal that, when cooled, fuses the surfaces as one.

An important difference between TIG and MIG is that the TIG arc is generally narrower and deeper than MIG and this results in welds that can penetrate deeper into the metal.

TIG can use filler material like MIG welding does, but does not have to.  The heat generated is powerful enough and deep enough to fuse the two surfaces and can do so without the splatter of MIG welding.

Because of TIG welding’s ability to create beautiful and clean welds, this is usually the technique of choice for welds that are visible so as for artists or ornamental welders.

What is TIG welding used for

TIG welding is routinely used for space as well as automotive needs, where the weld quality if of the highest nature and with minimal disruption of the surrounding metal. A good looking weld finish is icing on the cake.

TIG works well with steel, stainless steel, aluminum, chromoly, copper, brass, and exotic metals such as titanium and magnesium.

Space and Aircrafts– you’ll see a lot of TIG welding here due to the need to bond thin metals with high quality welds, something that TIG welding is well suited for.

Pipes and Tubing – since these are inherently thinner metals, TIG is often used for precision welds.

Art – welding artists that like the beautiful and clean weld lines opt for TIG.  This is not to say that they only use TIG here, just that on art where those clean lines are desired, TIG is the prefered welding method.

TIG vs MIG welding strength

Which provides the strongest weld is a common question and is a bit misleading.  Underlying factors will determine which results in the strongest weld.

Given proper set up and penetration, properly done TIG and MIG welds will have the same tensile strength as they use the same filler metal.

The determining factor of the eventual strength of the weld is defined by the Heat Affected Zone (HAZ).  Heating the metal to be joined compromises that metal due to thermal expansion.  The more it’s heated, the less the metal can withstand stress.

It is the metal itself, rather than the weld, that is often the catalyst for a “failed weld”.  The weld with the smallest HAZ can be considered the strongest of the welds.  This is where TIG shines.

To be clear, a MIG weld is as strong as a TIG weld, but the underlying metal is compromised more due to the heat distribution inherent in MIG welding.

In the end, the determining factors for the strength of a weld are the filler metal type and how wide/deep the weld is.  How “good” the weld is, of course, is the final and most important factor.  A good MIG weld will be stronger than a bad TIG weld, and vice-versa.

TIG vs MIG welding comparison

 

MIG TIG Comments
Ease of use/ease of learning X
  • MIG requires only one hand, the overall process is easier to master
  • TIG requires both hands and the use of a foot pedal, the overall process is more difficult to master
Welding speed X MIG is faster while TIG allows more control and a stronger weld
Precision of weld X MIG has a wider arc while TIG allows for a more precise and deeper weld
Final appearance X TIG welds are often the most beautiful.  Artists and ornamental welders usually TIG weld
Thickness of metal Thick Thin MIG excels at working with thicker metal since the filler heats and bonds to the surfaces while TIG is great for welding thinner metals.
Cost $ $$ Setting yourself to weld using TIG will cost you about twice as much as MIG, all other things being equal.  Of course you can buy an expensive MIG set up that is costlier than a TIG but if you are looking at relatively equal systems, TIG will be more expensive

TIG vs MIG welding conclusion

I think you’ll see from the above that neither is “better” than the other.  Both work well in their spaces.  MIG welding is preferred and is better for situation and for welders where MIG welding is needed, and the same can be said for TIG welding.  That being said, each does have clear benefits over the others for specific situations so it’s helpful to understand those differences.

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