“MIG” stands for “metal inert gas” and “TIG” stands for “tungsten inert gas.” With MIG welding, a powerful electrical current is generated through the torch and arcs through the consumable electrode, joining the metal together and reinforcing the joint with added material. The TIG welding process is similar, except the electrode in the torch is made of tungsten and not consumable. A secondary filler rod of consumable material is used to reinforce the weld.
There are 7 key differences between MIG and TIG welding to keep in mind for your project:
1. Power source
MIG Welding Power Source
MIG welding uses a DC (direct current) power source because it’s reliable and provides for less weld splatter or mistakes in the weld. DC is better for thinner materials and gives the welder more control over the welds.
TIG Welding Power Source
TIG welding can use both DC and AC (alternating current) power sources. This versatility is important for more experienced welders as it allows welders to select a power source suited for the specific material being welded.
2. Metal selection
Most metals can be welded using both the MIG and TIG methods, but some metals are better welded using one method over the other.
Metals for MIG Welding
MIG is best suited for welding laser cut mild steel and cast iron. MIG welding does not produce the most aesthetic welds, but these metals are easy to work with and can handle further processing to make the welded joints look smooth and clean.
Metals for TIG Welding
TIG is best suited for welding laser cut aluminum and stainless steel. TIG welding is far more precise than MIG welding, so is perfectly suited to these metals that need to be handled and joined with care to avoid warping.
MIG Welding Electrode
As mentioned above, the electrode used in MIG welding is consumable. It is placed inside the torch and melts the metal to be joined with an electrical current. The electrode then bonds to the welded metal and reinforces the welds.
TIG Welding Electrode
The electrode used in TIG welding is made of tungsten and is not consumable. The tungsten rod merely delivers the electrical charge and a separate rod of filler material is held and melted to the welds.
4. Shield gas
MIG Welding Shield Gas
The most common blend of shield gas in MIG welding is argon and carbon dioxide. This blend is suited for thicker metals, although the gasses used are sometimes too light and susceptible to being carried off by a breeze or minimal movement, causing the welds to be left unprotected. Flux-core welding is a type of MIG welding which does not require a shield gas supply.
TIG Welding Shield Gas
The most common blend of shield gas in TIG welding is argon and nitrogen or helium, or just pure argon. The shield gas used in TIG welding prevents the electrode from overheating, and is heavier than oxygen so is more capable of protecting the welds from air bubbles and splatter.
5. Welding quality
MIG Welding Quality
MIG welds are strong and durable and best suited for high stress, heavy duty applications. It is difficult to create precise, aesthetic welds using MIG welding, but the durability in thick materials is unmatched.
TIG Welding Quality
It is easier to create small beads and precise, aesthetically pleasing welds with the TIG welding method. TIG welding is also stronger and better suited for thin metals with more delicate applications.
MIG Welding Speed
Since the welding torch feeds the filler rod automatically, MIG welding is typically much faster than TIG welding. MIG welding is the first choice for high production applications due to its speed.
TIG Welding Speed
Because the welder has to supply filler rod manually, TIG welding is simply not as fast as MIG welding. The tungsten electrode in TIG welders also overheats faster when air cooled so need to rest more often.
MIG Welding Cost
MIG welding units are lower cost than TIG welding units. There is significantly less prep work needed for MIG welding, and because it’s faster than TIG welding, overall it’s the more affordable option.
TIG Welding Cost
The precision found in TIG welding does come at a cost. TIG welding units are more expensive and the slower speed TIG welding requires makes it cost more overall to TIG weld rather than MIG weld.
Is TIG better than MIG?
It is difficult to determine whether TIG is better than MIG, as it depends on a number of factors. TIG offers greater weld strength and better aesthetics if completed properly by a skilled welder but, if the welder is less skilled, MIG welding may be a better option for a quality weld. MIG welding is also a faster process than TIG welding, allowing for longer runs to be completed in less time. So, ultimately, TIG is better in some instances and MIG is better in others.
Is TIG welding harder than MIG?
TIG welding is typically seen as more difficult to master than MIG welding as it is a less automated process that requires greater precision.
Should I learn MIG or TIG welding?
While stick welding is often considered to be the best process for total beginners, MIG welding is a better place to start learning the basics over TIG welding. You should be able to produce acceptable welds much easier with MIG than with TIG.
How to choose the right process for your application?
The differences between the two welding techniques mean that it can be difficult to decide when to use MIG and when to use TIG welding. Each technique has its own advantages, which can act as a guide to which technique to choose…
1. When to use MIG:
- Thicker materials – MIG is better suited for joining thicker stock
- Long runs – The continuous wire feed of MIG welding means that it is better for longer runs, needing to stop and start less often to replace the filler material than with TIG welding, which means less chance of weld defects
- Difficult positions – MIG is easier to use in difficult positions as it only requires the use of one hand
- High productivity – MIG welding is better suited to high levels of productivity than TIG welding, which is a slower process
- Less experienced welders – MIG is easier to learn than TIG, so is better suited to less experienced welders
2. When to use TIG:
- Thinner materials – The precision and accuracy of TIG welding means that it is ideal for joining thin materials that may be susceptible to burn through or warping
- Short runs – TIG welding is best suited to short runs
- Shop or bench work – TIG is not an easy process to manage when out of position, so the best results are achieved in bench or shop work
- Delicate or fine work – TIG welding is preferred when the look of the final weld is important. Visible pieces such as automotive restoration or artwork will look better with TIG welding, while the process also allows for better control to prevent warping or burning
- Non-ferrous metals – Experienced welders will tend to turn to TIG welding for aluminium, copper, stainless steel and other exotic metals
- Experienced welders – All of the advantages of TIG welding depend on having an experienced welder, without which it is better to opt for a simpler method, such as MIG welding
MIG welding uses a continuously-fed electrode wire and shielding gas via a hand-held torch. TIG welding uses a non-consumable tungsten electrode with a shielding gas fed through a supply line and a separate, hand held filler rod that is manually fed into the weld pool. TIG welding also uses a torch mounted control or a foot pedal to change the amperage. Both types of welding typically use different shielding gases too.
Neither MIG or TIG can be deemed ‘better’ than the other as they both have their own advantages and disadvantages depending on the situation.
MIG welding offers low cost, fast welds and is easy to learn, meaning that less experienced welders can put down good quality welds. TIG welding is much more difficult to master as well as being more expensive and slower. However, TIG welding can deliver a level of accuracy and aesthetic quality that can’t be matched by MIG welding. Where MIG welding is better for thicker materials, TIG welding is preferred for thinner materials or more delicate jobs.