TIG vs. MIG – Which Type of Welding is Best?

Tungsten inert gas(TIG) and Metal inert gas(MIG) sounding similar are the two common welding processes, both yielding different results.

Although MIG and TIG have similar aspects, such as using inert shielding gas and heat generated by an electric arc, still, there are many key differences.

To help you out in this confusion, we have explained the in-depth facts about the MIG vs. TIG welding process in today’s article so that you can make the right decision per your requirements. Remember, both are good under some particular circumstances. You should first identify your requirements before concluding anything.

MIG VS TIG Welding – Working Mechanism

The main difference between MIG & TIG is the electrode used to strike the arc.MIG welding uses a consumable electrode continuously flowing through the gun to strike the arc and acts as a filler to form the weld. On the other hand, the electrode used in TIG welding is non-consumable.

MIG Welding Process

It’s a well-known welding process having many acronyms. But MIG (metal inert gas) is the one that is widely used. But some also name it GMAW(gas metal arc welding).

We won’t be discussing the whole MIG process in depth as it can get wordy. However, generally, it uses an automatic or semi-automatic arc to form a weld.

It also uses a shielding gas and a consumable wire electrode(acts as a filler metal)that constantly keeps flowing the welding gun(torch) to create the weld.

The wire’s composition and diameter will vary for each metal you weld according to its thickness and joint type.

Electrode wire has different spool sizes, and the MIG welder feeds it to the welding gun (torch), where it gets used. Therefore, WFS(wire feed speed) is one of the key settings in the MIG welder and must be set to offer the optimum weld metal amount for the joint being welded.

The MIG welder’s shielding is a composition of argon(75%) and CO2(25%), which enhances the weld force and lowers bead porosity. But, shielding gas differs for each metal you weld.

Advantages & Disadvantages of MIG Welding

Advantages

  • MIG welding consumes less time
  • MIG costs less than TIG welding
  • MIG yields accurate results
  • It’s an automatic process
  • Offers greater equipment accessibility
  • MIG welding results in cleaner weld

Disadvantages

  • Electric arc stability is not reliable as compared to TIG welding
  • Welding joints lack strength
  • Smokes and fumes are hazardous to the environment
  • Develops rust after sometime
  • Lesser operation control causes burn in thin metals
  • Welding settings differ for every metal
  • It can be carried indoors only due to shielding gas
MIG welding process
MIG Welding Process

TIG Welding Process

TIG(Tungsten inert gas) is the most common welding process, called GMAW(Gas tungsten arc welding).

TIG welding also uses an electric arc to produce heat, but TIG uses non-consumable electrodes that do not become filler metal, unlike in MIG welding. Besides, TIG welding uses pure 100% argon shielding gas with no blend of CO2, while MIG uses a blend of both.

You are needed to manually feed the rod of filler metal into the weld pool with your other hand, and an electric arc is produced by striking the non-consumable tungsten electrode. The TIG filler rod size and composition also change with the welding metal, the same as in MIG welding.

One of the added benefits of TIG welding is the foot pedal, which lets you control the heat going to the weld piece resulting in finer welds.

Advantages & Disadvantages of TIG Welding

Advantages

  • Offers more accuracy and precision
  • Delivers aesthetically appealing welds
  • Environmental friendly than MIG welding
  • Enhanced controls in operations
  • Less operational cost and maintenance because of non-consumable electrode

Disadvantages

  • Filler metals and slower processes make TIG welding costly
  • The welding surface must be clean
  • Requires extended time
  • TIG welder needs to be operated by a professional

TIG welding process
TIG Welding Process

MIG Vs. TIG Welding – Differences

The brief discussion above clearly depicts the differences between the two processes.

But does this difference affects the weld quality?

Yes, more than you think. Have a look at some of the important welding attributes.

TIG vs MIG Welding differences
Infographic: TIG vs. MIG Welding

Strength of Weld

TIG welders can deeply penetrate the metal because they produce confined and focused arcs resulting in stronger welds. For instance, tack welds from using a TIG welding machine are harder to break.

Additionally, TIG beads have minor defects, such as holes. These defects cause weak welds, meaning the lesser the defects stronger the weld joint. Many welders claim TIG welds to be stronger because of the deep penetration and minor visible defects, which we think have considerable truth.

But we think both methods are capable of performing durable and stronger welds. Besides, MIG welders can also penetrate better if considerable measures are taken.

Stronger MIG welds can be achieved using the right torch positions and optimum travel speed. Also, grinding or cutting V groove into the joint before welds helps in increased penetration.When a MIG welding is performed in a professional way , the weld strength could be more than the base metal or equivalent to it.

Speed of Weld

MIG welders are faster than TIG welders when it comes to weld speed.TIG welder results in aesthetically appealing welds, but we think at the price of slow speed. But, MIG welders can fastly move the weld puddle and supply enough filler electrodes, while TIG is not capable of doing so.

TIG welding uses an air-cooled torch, which gets hot during prolonged welding hours, so you may need to switch to a more expensive and complex water-cooled torch at some point.

MIG welders have a broader and rounded arc better at heat dissipation. Also, the filler metal/electrode is fed automatically when using a MIG welder. These characteristics make the MIG welder move weld puddle faster and make longer runs using an air-cooled torch.

Heavy duty welding operations require machines capable of running for long periods and creating beads after beads without difficulty. For this reason, MIG welders are often used in industrial-grade operations where higher production is required.

Shielding Gas

Shielding gas plays a major role in the weld quality because it prevents reactive air gases from getting into the weld puddle. But, both MIG and TIG processes use different shielding gases.

MIG welding machines use a gas that is composed of Argon and CO2. The CO2 is in smaller quantity which aids in deep penetration and stable arc.

In comparison, the TIG welder uses 100% Argon gas with no other mixed because the tungsten electrode has a sensitive reaction to other gases like oxygen and CO2.

argon gas flowmeter

But while carrying out some special welding tasks, Argon is mixed with other gases like hydrogen, helium, or nitrogen.

However, MIG welder also utilizes different gas for special welding applications. For example, welding aluminum with a MIG welder uses 100% argon gas. However, MIG welding with pure CO2 is also possible, which costs less and offers deep penetration but also has some disadvantages, such as welds looking bad aesthetically.

The flow rate of the shielding gas must be set right also. A TIG welder uses 15-25 cubic feet of shielding gas flow per hour which is enough for most welding scenarios. In contrast, a MIG welder uses 35-50 cubic feet of gas per hour.

Aesthetics of Weld

A TIG welder produces aesthetically good-looking welds, having no spatter and smoke. They often no or little polishing to eliminate any discolouration. So TIG welders have the edge over MIG welders regarding weld visual appearance.

In the case of aluminum or stainless steel, which is neither coated nor painted, TIG welding is widely used to make the finishing product more appealing to the eye.

But that does not necessarily mean that MIG welds are bad. A professional welder can also perform good-looking welds with the MIG process. Besides, many welding projects require aesthetic looks that can be easily achieved using a MIG welder.

In many welding tasks, paint is often required to hide the welding defects, such as steel. So it’s common to weld metals using a MIG welder.

Weldable Metals

Aluminum

Welding aluminum is quite challenging as it’s a great conductor of heat. Besides, as soon as the aluminum is exposed to air, a natural aluminum oxide layer shows up on it, resulting in arc disruption. Both of these factors make it hard to weld aluminium.

So establishing a feasible ground and good heat control is essential, as well the as the arc must be stable enough to penetrate the aluminium oxide layer. A TIG welder with a foot pedal offers more control over the heat, which immensely helps aluminum welding.

tig welding aluminum
TIG Welding Aluminum Using Canaweld TIG Welder

The AC current that a TIG welder uses aids in better cleaning the annoying aluminum oxide layer found on the surface, opposite to DC welding. This is one of the main reasons the TIG welding machine is a good option for welding aluminum.

Also, aluminum is mostly uncoated, like stainless steel.So that means we need to perform the weld using a TIG welder to achieve the desired appearance.

You can also use a MIG welder to weld aluminum. However, it is more vulnerable to being affected by atmospheric gas contamination and deformity caused by minor amounts of moisture or air. So, the metal piece you will weld must be well prepared and cleaned. Additionally, ensure your aluminum feed wire is fresh, dry and clean.

Another issue that you are going to face when MIG welding aluminum is dealing with feeding the soft aluminum wire to the torch, which often tangles. So we recommend you use a spool gun to minimise the tangling of wires.

All these precautionary measures will help you move the process more quickly and increase MIG welder productivity when welding aluminum.

Stainless Steel

Stainless steel is a good conductor of heat like mild steel, causing it to deform at high temperatures and sometimes get distorted once it cools down.

So such a condition makes it challenging, particularly for beginner welders. However, you can tackle this issue using a TIG welder with a foot pedal. This will make you control the heat according to the welding need.

Additionally, the arc produced by a TIG welder torch is more precise and narrow, making it a suitable option for welding thin metals like stainless steel.

man welding metal bars
Image Credit: Pavel Chernonogov, Pexel’s

Commonly argon shielding gas is mixed with helium or nitrogen when TIG welding stainless steel. But it differs depending upon the specific stainless steel alloy being welded.

But, sometimes, welding SS with a MIG welder with a pulsed current feature could be a better option. If you need to weld complex joints, have challenging welding positions, or want to obtain high productivity, using a MIG welder can be the best option.

Cost

The less deposition rate and slow nature of TIG welding increase the bead per foot cost, making it costlier than MIG. Besides, the job will be carried by a professional welder, which costs more. Initially, a TIG welder costs more than MIG. The consumables it works with are expensive.

While on the other hand, MIG welders are quite cheaper than TIGs.Additionally, the speed MIG welders offer lower the bead per foot cost. Plus, working prerequisites are comparatively lower than the TIG welding process.

These are the main reasons MIG welds are lower in cost than TIG welds.

MIG and TIG Welding Applications

The comparison between MIG and TIG welding process cant be concluded without knowing when and how to opt for the best option. The aforementioned advantages and disadvantages can help you choose the most suitable method. So, we are letting you know the applications of these two processes.

MIG Welding Applications

It’s one of the most widely used sheet metal welding methods in the home improvement and automotive sectors. We discussed some of its applications below.

  • Big Metal Parts:
    It’s suitable for welding big and thick metals, using a filler metal that creates stronger bonds. But smoothing the weld joint is necessary. Besides, the constant feed wire makes it more productive than TIG welding, where you need to feed the wire manually.
  • Lower Defect Welding Scenarios:
    Constantly fed wire enables the MIG process for longer runs, meaning you don’t need to stop and start again and again, which minimises the chances of the defect, unlike TIG welding, where you need to stop after some time for rod adjustment or getting new rods, which results in welding defects in longer beads.
  • Welding in Challenging Positions:
    Running a MIG torch requires using a single hand, which lets you hold pieces or balance yourself. This means you can tackle difficult welding angles quite well.
  • Achieving Higher Productivity:
    If you are to achieve higher production rates, it can’t be done any better than MIG welding. It’s capable of producing more feet of beads than TIG welding and inducts more pounds of filler material.
  • Beginner Welders:
    The MIG welding process is easier to learn as compared to TIG. A welder with lesser experience can also lay good beads in a project.

TIG Welding Applications

TIG welding is most suited for the following metals.

  • Thinner Guage Metals:
    A TIG welder is capable of welding thin gauge metals that are vulnerable to burn through and warps with utmost precision and accuracy.
  • Ferrous Metals(Aluminum):
    Experienced welders often opt for TIG welding to weld ferrous metals such as aluminium, copper, stainless steel and other appropriate metals. But, it won’t welds ferrous metals like cast iron.
  • Indoor Welding Tasks(Home and Shop):
    The jobs where you have the right positions such as a shop or homework, TIG welding is the most suitable candidate. But it won’t work well in outdoor welding scenarios where air disrupts the shielding gas.
  • Short Run Welds:
    It’s the most suited for short-run productions such as welding pipe joints. However, its cost & complexity increases when used for long production runs.
  • Aesthetically Appealing Welds:
  • When you are looking for a weld with no spatter and smoke, and one that looks appealing visually.TIG welding is your best bet.
  • When a weld needs to aesthetically appeal, TIG welding is the best call. For instance. Welding delicate pieces like automotive restoration, ornamental designs etc can only be carried out by using a high-quality AC/DC TIG welder.

Why MIG Welding is Better Than TIG?

The following are the factors that make MIG welding ahead of TIG welding.

  • Diversified Applications:
    MIG welding offers more diversity because of its metal compatibility and utilizing the consumables electrodes. These consumables act as the filler which makes it ideal to bond two different metals.
  • Faster in Speed:
    MIG is quite faster as compared to TIG because a MIG welder is either fully automatic or semi-automatic. The welding gun constant flows, resulting in higher products.
  • Easy to Use:
    MIG welding is a single-hand operation, unlike TIG welding where you need to use both hands.MIG welding can be performed by a novice welder having little expertise, whereas in TIG welding a professional welder is able to execute the job.

Wrapping Up

Both MIG and TIG have pros and cons. The use of the process depends on certain welding scenarios and varaibles you need to address.

MIG welding is a relatively low-cost and high-production process. Capable of welding metals like alumimum and steel. Though it can weld stainless steel too but is the area where MIG welders are not primarily used.

On the other hand, TIG welds are capable of producing visually appealing welds but offer low production. Besides it’s an expensive process and requires a professional welder. Its mostly used in welding applications where the bead is apparent such as thinner metals, aluminum, pipe joints and stainless steel.

TIG welder can also weld steel, but we recommend you use a MIG welder as steel is something that doesn’t need to be aesthetically appealing. So you don’t need to use a TIG welder as it incurs more cost.

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About Dave Walker

Dave Walker, a professional welder who has been welding from an early age. Now aims to help others by making them learning skills and finding them new opportunities. He has written for many welding blogs and helped many pursue their welding goals by helping them in choosing the best welding tools of the time.