MIG vs. TIG Welding

Joining metals together through welding gives you several options for the best method. Among your choices are MIG welding and TIG welding — both offering specific benefits in certain situations. The MIG vs TIG welding debate has been popular in the manufacturing industry for some time, and we’re here to provide the facts for each type of welding.

If you ever wondered what the difference is between MIG welding and TIG welding, this guide will cover everything you need to know.

Table of Contents

• Basics of MIG Welding and TIG Welding
• Advantages and Disadvantages of MIG and TIG Welding
• Differences Between the MIG and TIG Welding Processes
• Applications and Use Cases for MIG and TIG Welding

Basics of MIG Welding and TIG Welding

Both MIG and TIG welding create a weld by heating a metal surface with an electric arc. The difference lies in how the arc is used to join the metal surfaces. MIG welding uses consumable rods, also known as consumable electrode fillers, that the arc melts to produce a weld. TIG welding does not require a filler material — instead, it relies on a Tungsten tip to heat and join the metal surfaces directly.

What Is MIG Welding?

Metal inert gas (MIG) welding also goes by the name gas metal arc welding (GMAW), and most welders learn this process first because it combines versatility with ease of use. Most metals and alloys adapt readily to the process.

The inert gas portion of the name comes from the fact the arc does not react to the oxygen in the atmosphere. A shielding gas surrounds the electric arc to prevent it from acting outside its designated area. This gas helps to increase the safety of MIG welding.

The welder uses consumable electrodes in the form of metal fillers. This metal will melt to connect the pieces of metal the welder wants to join. The type of electrode filler you use depends on the materials you need to join and their properties.

MIG welding offers a straightforward process compared to other forms of welding. Its simplicity makes the process quick, so it’s ideal for last-minute projects, especially if you must join thicker metals than TIG welding can handle.

What Is TIG Welding?

TIG welding is an acronym for tungsten inert gas. Its other name is gas tungsten arc welding or GTAW. The name for the process comes from the tungsten electrode inside the welding gun. In MIG, this electrode is a consumable metal that creates the filler. Tungsten, however, melts less readily than other materials. It conducts the arc of electricity directly to the components you need to join.

Unless you touch the tungsten electrode to the weld pool or materials, you will not consume it during the process. Should the tungsten touch the metal, an incident known as dipping, you will need to grind off the tip. How often you accidentally dip the tungsten into the metal determines the life of the tip.

TIG requires two hands to weld, so in instances that use a filler, the welder controls the current using a foot pedal. Unless the welder regulates the current properly, the metals could get too hot. If the metals overheat during welding, they could crack from the stress.

Since TIG welding requires you to heat the metal pieces you need to join, the parts must be thin enough to allow the current to pass through them to reach the proper temperature. Very thick pieces require the filler used in MIG welding for a more secure bond.

Advantages and Disadvantages of MIG and TIG Welding

MIG and TIG welding have several applications. Before identifying specific uses, though, be aware of the benefits and drawbacks of MIG and TIG welding to see how they suit themselves better for some projects. Although you may have a preference, it is helpful to know the pros and cons of each so that you can make an informed decision between these welding techniques.

Advantages of MIG Welding

Some of the advantages of MIG welding include:

• Faster welding time: If you need speed over precision, choose MIG welding. MIG welding offers the benefit of efficiency. The process takes much less time compared to stick or TIG welding. For applications that require the fastest weld possible, MIG welding may be the best choice.
• Ease of use: This type of welding is more accessible and the type of welding that most beginners will start with. It also usually provides satisfactory results regardless of skill level.
• Better for thick pieces: Consider the metal thickness and appearance of the weld. For thicker metals, the filler used in MIG welding will help hold the parts together. Therefore, when connecting thicker pieces, MIG welding offers an advantage over TIG. The filler used for MIG welding better adheres the metal parts together, and thicker metal takes longer to heat for TIG welding to work.
• Material versatility: MIG welding is far more versatile than TIG welding, and you can work with a wide range of metals, including aluminum, stainless steel and even mild steel.
• Cost savings: MIG welding material is more readily available, most welders are familiar with the process and the overall costs are notably more affordable.
• Less wastage: Unlike other forms of welding that have a consumable filler, such as stick welding, MIG uses more of the filler material, producing less waste. For example, in stick welding, up to 25% of the filler electrode goes to waste as an unused stub. With MIG welding, for every 50 parts, 49 of those will deposit onto the metals as filler, leaving less than 2% as wasted filler.

Disadvantages of MIG Welding

Some of the drawbacks of MIG welding are:

• Hazards and limitations: While useful, fast and versatile, the biggest drawback of MIG welding is where you can do it. The gases used to shield the welding process do not perform well outside. Only conduct MIG welding indoors, with a better-controlled atmosphere.
• Less clean weld: It occurs faster, though the results do not appear as clean as with TIG welding due to less precision.
• Material thickness concerns: MIG welding is only appropriate for thicker materials, as you are likely to burn straight through thinner materials.

Advantages of TIG Welding

Some of the advantages of TIG welding include:

• Higher precision: While MIG uses a filler, TIG does not require one. Its ability to conjoin two metals without a filler means the parts have a cleaner joint without defects from misused filler material.
• Cleaner welds: When working without filler, TIG welding creates finished products with no visible weld filler above the surface. TIG also does not generate splatter during the process, since it does not need filler to create a bond.
• Better suited to thinner materials: TIG works exceptionally well with incredibly thin metal sheets and does not need filler for such welds. Parts that do not conduct electricity well but heat up instead work especially well with TIG welding, which relies on heat generation in the metal to create a weld pool.
• Suitable for dissimilar metals: Whereas MIG should only conjoin like metals, TIG welding can bond dissimilar materials. For instance, you can weld together carbon steel with copper alloys or stainless steel.
• Greater options regarding filler: Although you can use a filler material, TIG welding does not always require it, and you will always need filler for MIG welding.

Disadvantages of TIG Welding

Some of the downsides of TIG welding involve:

• Requires a higher level of training: The TIG process requires more skill than MIG, which means only experienced welders will use this method.
• Metal thickness concerns: Consider the thickness of the metal. For thicker pieces, TIG will not produce adequate heat in the parts to join them. TIG does not suffice for metals measuring 1/2-inch thick because the materials cannot heat enough during the process.
• Slower process: The precision required for TIG welding considerably slows the process. TIG welding takes at least twice as long compared to a similar project using MIG welding. That time investment, though, ensures the product from TIG welding has a smooth, precise weld between a pair of metal sheets.

Differences Between the MIG and TIG Welding Processes

How does each process differ? Here’s an overview of how MIG and TIG welding work to give you a better idea.

MIG Welding Process

The process of MIG welding starts with thoroughly cleaning the metal surfaces you need to connect. Any dirt or contamination on the surface could prevent the filler from adequately adhering to the metal. Even dirt under the metal clamps holding down the parts could impede electrical current through the system, reducing the effectiveness of the weld.

During welding, power flows through the welding gun to the wire. The weld sends an electric arc through the consumable electrode to the metal pieces. This process melts the consumable filler into a weld puddle that will cool and solidify to join the metal pieces.

Setting up the parameters for MIG welding depends on the metals you need to join.

• Amperage: The amount of current you use depends on the thickness of the metal. Generally, use one ampere per 0.001 inch of metal thickness.
• Filler electrode wire: The type of wire you use depends on the types of metal joined. The thickness of the electrode directly correlates to the metal’s depth.
• Gases: The gases selected also depend on the metals. For all-purpose welding of carbon steel, use a 75% argon and 25% carbon dioxide mixture. Using 100% carbon dioxide gas allows for deeper filler penetration for thicker metals, though it creates more mess. For aluminum, use 100% argon, while equal parts argon, carbon dioxide and helium work well for stainless steel.
• Stickout: The length of wiring jutting from the end of the welding gun should measure 3/8 inch and produce a bacon-sizzling sound when used. You have too much wire out if the sound production does not match expectations.
• Push or pull: During this process, you can push the welding gun forward or pull it backward. The choice depends on your skill and the results you want to produce. Regardless of your chosen method, aim for a travel angle between 5 and 15 degrees between the surface and the welding gun. Angles measuring higher than this can increase splatter and reduce accuracy.

The difference between pushing and pulling is that:

• Pushing means you work ahead of the weld puddle, creating a shallower penetration and flatter weld. This method gives you better visibility of the process because you push away from the pool.
• The pulling process requires you to drag the gun away from the puddle. Some call this the backhand method because your hand moves backward. Pulling the welding torch away makes a narrow bead that penetrates deeply.

TIG Welding Process

Unlike the MIG process, which only requires one hand to hold the welding torch, though two hands for steadiness is preferable, TIG welding requires two hands if using a filler material. While the filler is inside the welding torch in MIG welding, you hold it with one hand during TIG welding.

For the best TIG welding results, you should also try to ensure the cleanliness of the welded surfaces. Dirt causes serious complications with the weld, especially when using TIG without filler. Taking the time to clean the surface and to complete the weld will create a better weld than if you rushed through with dirty surfaces. 

If you need a filler for the process, you hold a rod of the material in one hand while you have the torch in your dominant hand. You use a foot pedal to regulate the current through the welding gun.

• Amperage: The welding torch sends an electric current to the metals joined. This current heats the metals, enabling them to melt slightly to create a weld puddle between them. Since the electric current heats the metals, TIG welding works best for extremely thin pieces, as narrow as 0.005 inches. MIG welding would overwhelm such thin sheets of material.
• AC vs DC and type of tip: The tungsten rod will have a point or a rounded ball end, depending on what you will weld and the power source. For aluminum and magnesium welding, use AC power and a ball end on the tungsten. Stainless steel and steel use direct current electrode negative (DCEN) and a pointed tip on the tungsten.
• Filler electrode wire: For the TIG welding process, tungsten fits into the welding torch where the consumable filler would be in MIG welding. This tungsten retains its form during the process, allowing for repeated use.
• Gases: With TIG welding, use argon gas, whether joining stainless steel, aluminum or steel.
• Push or pull: While push and pull both work well for MIG welding, with TIG, always use the push method.

TIG welding requires extreme care and precision. Don’t be afraid to take time. While a slower process, TIG welding produces much more aesthetically pleasing results.

Applications and Use Cases for MIG and TIG Welding

In general, MIG welding is typically used for welding together thicker metals. MIG welding is also faster than TIG welding, making it a great option for applications that require speed. If you have experience with welding and need a strong, corrosion-resistant, visually appealing connection and have the time to devote to the process, choose TIG welding.

Here are specific applications and use cases for each welding type:

What Is MIG Welding Used For?

As long as you match the gas and wire to the types of metal you need to conjoin, MIG has a wide variety of applications you can use it for. Because it produces a visible weld line, choose it for projects that you can see from the outside or where the aesthetics matter.

Appropriate uses for MIG welding include the following:

• Metal component repairs
• Automotive repairs and manufacturing
• Trailer hitches
• Farm equipment
• Construction welding
• Pipe welding
• Underwater welding projects
• Railroad track repair
• Shipbuilding

These options for MIG welding show how versatile the process is. As long as your project does not need to look perfect, requires speed for finishing or has thicker metals that TIG welding won’t work for, you can choose MIG for your welding.

What Is TIG Welding Used For?

Since TIG requires extreme precision and produces cleaner welds, it’s best suited for applications where appearance and strength matter. 

When choosing TIG welding, the parts must fit tightly together before welding them. If not, the weld will not correct any errors in fit since TIG generally does not use filler. Should the parts not have the desired fit, you can still use TIG if you do the welding with a pulsed current. While this may not fix problems with fit, it accommodates the parts better.

TIG welding has some applications required by construction codes. For many projects, a minimum of the first weld between parts must use TIG welding. These applications include:

• Piping
• Visible consumer goods
• Nuclear work

Since TIG welds do not have visible filler when finished, they work well for piecing together:

• Auto body parts 
• Aerospace components 
• Ship parts
• Bicycle parts 
• Pipes 

These applications also value the corrosion-resistance and strength of welds TIG produces.

One use of TIG welding that showcases its strength and reliability is its use for spent nuclear fuel. After nuclear rods have completed their use, welders choose TIG welding to seal these still radioactive substances to prevent leaks of the material inside.

Contact PBZ for Full-Service Manufacturing

Welding is a vital part of any metalworking project. At PBZ, we understand this concept, which is why we hire only certified welders who can successfully do both TIG and MIG welding to fulfill the widest variety of jobs. These welders make up a part of our team, offering our customers resourceful manufacturing from design through shipping. If your business needs a comprehensive service, contact us at PBZ Manufacturing.

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Updated March 12, 2024. Originally published November 4, 2019.