Mig Vs Tig Welding (What is Difference Between Them).

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.

What is Metal Inert Gas (MIG) Welding?

Metal Inert Gas (MIG) welding is an arc welding process that uses a continuous solid wire electrode heated and fed into the weld pool from a welding gun. The two base materials are melted together forming a join. The gun feeds a shielding gas alongside the electrode helping protect the weld pool from airborne contaminants.

Metal Inert Gas (MIG) welding was first patented in the USA in 1949 for welding aluminium. The arc and weld pool formed using a bare wire electrode was protected by helium gas, readily available at that time.

From about 1952, the process became popular in the UK for welding aluminium using argon as the shielding gas, and for carbon steels using CO2.

CO2 and argon-CO2 mixtures are known as metal active gas (MAG) processes. MIG is an attractive alternative to MMA, offering high deposition rates and high productivity.

What is Tungsten inert gas (TIG) Welding?

Tungsten inert gas (TIG) welding is a precise and versatile process used to create high-quality welds. It joins metals using a non-consumable tungsten electrode while protecting the welding area from atmospheric contamination with an inert gas such as argon.

The exceptional control and versatility of TIG welding, which can join a variety of metals including copper, aluminum, and stainless steel, are its main selling points.

The method forms an electric arc between the tungsten electrode and the workpiece which produces a great deal of heat. It melts the metal while the welder manually inserts a filler rod into the molten pool to add more material. Once it cools, the pool forms a solid bond.

TIG welding has many advantages, including excellent weld quality, exact control over heat input, minimal spatter, and the ability to create welds that are pleasing to the eye.

The Key Differences between MIG And Tig Welding

MIG Vs TIG Welding

We have already mentioned some of the differences between MIG and TIG welding processes.

MIG is generally seen as being easier to learn and perform as well as being faster and better for welding thick materials. However, TIG welding offers greater control and precision, is better for thinner materials and offers neater welds with little finishing required.

Aside from these general differences, there are a number of key differences that can be categorised according to different properties, cost, ease of learning, and more:

#1. Weld Strength

TIG welded joins are typically stronger than those produced by MIG welding. This is because the narrow, focused arc created by TIG welders offers better penetration of the metal.

In addition, the TIG weld beads, when applied correctly, contain few holes and other defects that can weaken the weld.

Despite this generalisation, MIG welds can still produce strong welds with good penetration by grinding or cutting a V-shaped groove into the joint before starting to weld to increase penetration. Good travel speed and torch positioning will also improve the weld strength of MIG welds.

#2. Weld Speed

MIG welders typically provide faster welding speeds in a production setting. This is because air-cooled MIG welders automatically feed filler material into the weld pool and have a rounder and broader arc that dissipates heat better.

This allows welders to move the weld puddle faster and make longer runs without overheating. By contrast, TIG welders cannot move the weld puddle as fast or supply enough filler rod to compete with MIG welding speeds.

In addition, the air-cooled torches used in TIG welding get too hot during lengthy welding runs, meaning they need to cool or be swapped for more expensive water-cooled torches.

#3. Shielding Gas

Both MIG and TIG welding use a shielding gas ensure quality welds. The shielding gas protects the weld puddle from reactive gases found in the air that can cause impurities in the weld.

TIG welds typically use pure argon gas to protect the weld as the tungsten electrode is more sensitive to reactive gases like oxygen or CO2.

MIG welds are typically performed with a blend of argon and CO2 (typically 75/25%), as the small addition of carbon dioxide stabilises the arc and aids penetration. There are exceptions to these general shielding gas rules, depending on the application.

TIG welding may sometimes use a blend of argon with helium, hydrogen or nitrogen, while MIG welding is performed with 100% pure argon when welding aluminium and can be performed with pure CO2 to save costs and increase weld penetration.

The two techniques also use different shielding gas flow rates, with MIG typically using 35 to 50 cubic feet per hour and TIG welding operating a shielding gas flow of 15 to 25 cubic feet per hour.

#4. Weld Aesthetics

TIG welds tend to show better aesthetic qualities than MIG welds. With very little or no spatter, TIG welds usually only require light polishing to finish and remove any discolouration.

TIG welded stacks of ‘coins’ are often seen as the most aesthetically-pleasing weld and can serve to make unpainted welds (in steel or aluminium, for example) look their best.

By contrast, MIG welds have a less desirable appearance, even though an experienced welder can still create good-looking MIG weld beads.

Despite the aesthetic differences, MIG welds are often fine for applications where appearance is less important or where the welds are to be coated, covering the appearance of the joint.

#5. Process Difficulty

MIG welding is much easier to learn and master than TIG welding. TIG welding requires the use of two hands, one to move the welding torch and the other to feed the filler rod into the weld pool. Plus, there is often a foot pedal with which you can control the amperage.

While these various movements allow for greater control, they can be difficult to master. The metals to be joined must also be cleaned and prepared well for TIG welds and welders tend to consider TIG as a more advanced process.

MIG welding, by contrast, is much easier to learn. There is no foot pedal to master and the filler material is automatically fed through the welding gun, meaning that you only need to use one hand to complete the weld.

#6. Cost

TIG welding costs more per foot of bead than MIG welding. This is due to the lower deposition rates associated with TIG as well as the need for more experienced, and thereby more expensive, welders.

In addition, TIG welding requires more prep work, which also adds to the cost. Finally, MIG welding supplies and machines tend to be less expensive than TIG. All of these factors combine to make TIG welding more expensive than MIG welding.

When To Use MIG vs. TIG Welding

There isn’t really an overall winner in the MIG vs. TIG argument. Although these types of welding are interchangeable to some extent, each has its strengths and weaknesses.

Understanding these pros and cons is the key to knowing which welding process will produce the best results. Although there are occasional exceptions, the following is a useful overview:

#1. Heavy-duty jobs.

Both standard MIG and gasless (flux-core) welding are the best choice for larger jobs. They can deposit great quantities of filler quickly and weld substantial thicknesses in a single pass.

While TIG welding can achieve the same in multiple passes, it’s rarely a practical solution, and applying weld on weld using TIG is much slower.

#2. Precision jobs.

Mild steel, stainless steel, and aluminum can all be successfully MIG welded, but control can be difficult—particularly with thin sheet metal.

It’s not unusual for beginners to burn holes through a workpiece. TIG welding offers greater precision, both in terms of the welding machine-provided adjustment and greater welder control.

#3. Long-run vs. small jobs.

Each TIG welding rod is around 3 feet long, so this process can involve a lot of stopping and starting. By contrast, a MIG welding spool contains several hundred feet of wire.

Given that MIG wire is fed automatically through the welding gun, MIG welding is almost always the better option for a long run of welding. TIG welding is excellent for small, detailed pieces, but it can be very time-consuming on larger jobs.

#4. One- two-handed operation.

MIG welding is done with just one hand. TIG welding requires two. This may not be important in a workshop, although one-handed operation can be useful for steadying a workpiece, ability, or comfort.

With awkward welding positions (more common jobsite welding), having another hand for balance might make the difference between safe and unsafe work. An out-of-control welding torch can be a very dangerous hazard.

At this point, it is worth mentioning welding safety and personal protective equipment (PPE). A welding helmet, welding jacket or apron, and proper welding gloves are all vital for avoiding burns and a painful type of eye injury known as “welder’s flash” or “arc eye.” Fortunately, the same high-quality welding PPE can be used for all forms of welding.