MIG vs TIG Welding: Key Differences Explained for Better Choice

MIG and TIG welding are two popular types of welding, each with distinctive advantages that vary due to the different electrodes used in each process. But although the processes differ in this important regard, they also share many characteristics, which sometimes makes it difficult to choose between them.

Because both methods rely on an electric arc generated by a welding machine, understanding how each setup operates is essential when evaluating MIG vs TIG welding performance.

This article serves to help engineers and product designers choose between MIG vs TIG welding, looking at the main characteristics, welding materials, and real-world applications for each process.

What Is Welding?

Welding is a manufacturing process used to join metals together. It does this by melting their edges, fusing them into a single, solid piece. You can see welding everywhere—in car frames, aircraft, pipelines, and sculptures, for example—and it is one of the most important processes both in metalworking and in modern manufacturing generally.

In essence, welding combines three important elements: heat, filler metal, and shielding gas. Together, these three elements lead to strong, long-lasting bonds that usually outperform adhesives and fasteners.

But welding isn’t a single, fixed process. There are many different types of welding, each suited to a specific metal, industry, or part. In general, types of welding can be divided into the following categories:

• Gas welding
• Resistance welding
• Arc welding
• Energy beam welding
• Solid state welding

What Are MIG and TIG Welding?

Within the subcategory of arc welding, two of the most common processes are MIG (Metal Inert Gas) welding and TIG (Tungsten Inert Gas) welding. These essential welding techniques both use an electric arc to melt metals, as well as a shielding gas to protect the weld from atmospheric gases that can weaken it and cause defects. However, they differ in other important respects.

Quality providers of sheet metal fabrication services will typically offer both MIG and TIG welding processes for assembly, though sheet is not the only suitable workpiece type.

What Is MIG Welding (GMAW)?

Metal inert gas (MIG) welding is one of two subtypes of gas metal arc welding (GMAW)—the other being metal active gas (MAG) welding.

The MIG process uses a semi-automatic or fully automatic arc to make a weld. It is a consumable electrode welding method, which means that the continuous wire fed through the welding gun—controlled by the machine’s wire feed speed settings—acts as both the electrode (carrying the electricity) and the filler metal (the material that forms the joint).

During the MIG process, the arc is formed between the tip of the wire and the surface of the workpiece (the base metal being welded). This generates enough heat to melt both the wire and the base metal, allowing them to fuse together as they cool.

The inert shielding gas plays an important role in the MIG process. To stop the molten metal from reacting with oxygen and other atmospheric gases, an inert shielding gas (typically argon or helium)—one that does not react chemically with the metal in the melt puddle—is released near the weld, creating a stable environment and preventing defects. Argon is required as a shielding gas for the welding of non-ferrous metals, including aluminum and copper.

But that doesn’t mean that MIG cannot be used to weld steels and other ferrous metals too. Although the process was originally developed for non-ferrous metals, its exceptional speed meant it was later modified for the welding of steels, although this requires the use of a semi-inert gas, typically a mixture of argon and carbon dioxide.

Active gas mixtures (typically containing argon, carbon dioxide, and oxygen) can also be used for shielding, and these are also effective for the successful welding of ferrous metals. But in these cases, the process can be referred to as metal active gas (MAG) welding, not MIG.

MIG summary:

• Fast and easy process
• Consumable electrode
• Inert or semi-inert shielding gas

What Is TIG Welding (GTAW)?

Tungsten inert gas (TIG) welding, sometimes referred to as gas tungsten arc welding (GTAW), resembles MIG in certain ways. For one, it also uses an electric arc to melt the materials and form the weld. However, unlike MIG, the TIG electrode is not consumable; it is a non-consumable tungsten electrode that is separate from the consumable filler material.

What does this mean in practice? In short, it means that the separate filler material—in the form of a rod—must be manually fed into the weld pool, or weld puddle, using the hand not being used to direct the electrode. It’s a little slower and trickier to perform, but it gives welders a good deal of flexibility when joining metals.

Welders can also make a TIG weld without a filler material at all. Such welds are known as autogenous or fusion welds.

In some ways, TIG welding offers a greater deal of control over the welding process. Not only can welders choose the specific type and size of filler material rod—or whether one is needed at all—they can also control the amperage and adjust the welding heat using a foot pedal.

Because of these benefits, suitable TIG welding metals include aluminum, titanium, and exotic metals—basically all the materials that MIG can handle, plus a few more. In aluminum alloy manufacturing, it is one of the most important assembly techniques. Crucially, TIG is also better at making welds on small or thin workpieces.

Like MIG, TIG also uses a shielding gas—typically 100% argon or helium—to prevent atmospheric gases from interfering with the weld and causing defects. A big difference here is that you won’t find any semi-inert TIG gas mixtures containing carbon dioxide, as this can encourage the formation of unwanted tungsten oxide, negatively affecting both the electrode and the weld.

TIG summary:request a quote

• Precise but difficult process
• Non-consumable electrode and separate filler material
• Inert shielding gas

MIG vs TIG Welding: Key Differences and Technical Comparison

What is the difference between MIG and TIG welding? The table below shows, in simple terms, the practical differences between the two processes. In the following section, we explore the technical differences in greater detail, looking at how the differences in electrode, filler material, and other factors impact the resulting welds.

Comparison Table

 MIGTIGCostLowHigh (higher equipment, consumables, and labor costs)SpeedFast (automated wire feeding)Slow (manual rod feeding)Difficulty LevelEasyDifficult (greater manual coordination required)Weld StrengthHighVery highPrecisionModerateHighAestheticsFairGoodWorkpiece MetalMild steel, stainless steel, aluminum, copper, bronzeMild steel, stainless steel, aluminum, copper, bronze, titanium, zincWorkpiece ThicknessThickThin

Power Source and Arc Control

MIG welding and TIG welding are both types of arc welding. That means they both use electricity to generate the heat that melts the metals and allows them to fuse. In arc welding, a welding power supply is used: a portable box that provides or modulates an electric current.

The power source allows the welder to choose the amount of current and voltage, as well as whether the current is alternating current (AC) or direct current (DC).

• MIG power sources usually have constant voltage. Direct current is used to keep the arc stable. A semi-automatic arc or fully automatic arc is used.
• TIG power sources usually have constant current, varying the output voltage in order to maintain a steady current; this helps account for changes in arc length as the welder manually creates the weld. Alternating or direct current can be used depending on the material. A foot pedal is used to control amperage, letting the welder adjust heat throughout the process, which directly influences overall heat input and weld penetration.

Electrode and Filler Material

In arc welding, the electrode is the conductive metal stick or rod from which the arc connects to the base material.

A consumable electrode is one that melts during the welding process, acting simultaneously as the filler metal and therefore becoming part of the final weld. A non-consumable electrode is one that generates the electric arc but does not become part of the weld itself, instead remaining intact.

The filler material is a metal used to join together two workpieces, becoming part of the finished weld.

• MIG uses a consumable electrode. This is a metallic alloy wire of varying metal and size. The type and size of the electrode depends on the metals being welded, the joint design, and specifics of the workpiece surface. The consumable MIG electrode is fed through the welding gun or torch.
• TIG uses a non-consumable electrode and separate filler material. The electrode is made of tungsten or a tungsten alloy due to the very high melting temperature of tungsten. Its diameter ranges from 0.5 to 6.4 millimeters. The separate filler material comes in the form of a rod, which is fed into the weld pool by hand. This rod can vary in material and size depending on the base material and other factors.

Shielding Gas

An arc welding shielding gas is used to protect the weld area from oxygen, water vapor, nitrogen, and other atmospheric gases that can reduce weld quality or increase the difficulty of welding. Shielding gases are usually inert or semi-inert, meaning they have very low chemical reactivity.

The shielding gas can be deployed in different ways. In MIG and TIG welding, the gas is stored in a canister and released from the welding gun nozzle.

However, in different forms of arc welding this is not always the case. For example, in flux-cored arc welding (FCAW), the tubular electrode contains a flux core; when exposed to high temperatures, this internal core generates a shielding gas. Shielded metal arc welding (SMAW), on the other hand, uses an electrode with an exterior flux coating that performs a similar function, releasing a cloud of carbon dioxide.

• MIG shielding gas can be inert or semi-inert. A pure inert shielding gas like argon or helium may be used for the welding of non-ferrous metals. MIG welding for steel and other ferrous metals requires a semi-inert shielding gas (75% argon, 25% carbon dioxide, for example). Carbon dioxide, the least expensive shielding gas, increases weld heat but negatively affects arc stability and can increase spatter.
• TIG shielding gas is inert. Argon is the most common TIG shielding gas, resulting in high weld quality and aesthetics. Helium can also be used, offering good weld penetration and welding speed but posing arc striking difficulties. Argon-helium mixtures are another option, combining the benefits of each gas.

Base Materials

The base material of the arc welding process is the material of the workpiece(s) being welded. Arc welding variants are suitable for a range of base metals, from common metals like mild steel to more specialist and exotic alloys like Inconel.

• MIG welding materials include non-ferrous and, if a semi-inert gas is used, ferrous metals like mild steel. Thicker workpieces are easier to weld.
• TIG welding materials include non-ferrous and ferrous metals. MIG is preferred for thinner workpieces and difficult-to-weld metals like aluminum, titanium, and magnesium. It can accommodate a wider range of metals due to its AC/DC flexibility.

Weld Quality and Strength

The MIG welder vs TIG welder debate often comes down to the quality of the final welds. Both are capable of strong, high-quality welds with a range of metals. However, a skilled TIG welder can maintain a greater level of control over the weld, meaning that TIG is capable of producing stronger and more aesthetic welds with a greater level of precision.

TIG vs MIG welding strength is influenced by the more focused arc of the TIG welder, which can better penetrate the base material and allows the welder to carefully shape and stabilize the weld puddle for higher-quality beads.

• MIG welding produces welds of fair quality, precision, and strength. Quality can be improved by maintaining a consistent torch angle and travel speed.
• TIG welding produces welds of superior quality, precision, and strength. This is largely due to the greater level of control over heat and filler material placement, allowing the welder to make small and precise beads. Spatter is typically low, resulting in a clean finish.

Speed, Efficiency, and Difficulty

In the broader category of arc welding, both MIG and TIG welding are usually faster than manual metal arc welding (MMAW), otherwise known as stick welding. However, MIG is significantly faster than TIG due to its continuous wire feed.

MIG is also a more beginner-friendly process than TIG, requiring less expertise. The MIG process is similar to the operation of a hot glue gun, whereas TIG requires the use of both hands and one foot, necessitating a good level of coordination.

• MIG is faster, more efficient, and easier to master than TIG. Travel speeds are often in the range of 15–20 inches per minute.
• TIG is slower, less efficient, and harder to master than MIG, though its superior results can be worth the trade-off. Travel speeds are often in the range of 5–10 inches per minute.

Cost

Arc welding processes vary in cost in terms of professional services and in terms of equipment and consumables. Overall, MIG is less expensive than TIG, whether you are ordering professional welding services or doing the welding yourself.

• MIG welding costs include the initial equipment setup ($300–800 for basic equipment) and protective equipment, in addition to consumables like the electrode and shielding gas. Professional MIG welding costs less per hour than TIG welding.
• TIG welding costs include the initial equipment setup ($3,000 or more) and protective equipment, in addition to consumables like the filler material and shielding gas. Professional TIG welding costs more per hour than MIG welding due to the greater level of expertise required.

MIG vs TIG Welding Pros and Cons

The table below summarizes the pros and cons of MIG Welding, as well as the pros and cons of TIG welding.

MIG WeldingTIG WeldingProsConsProsConsRelatively easy to masterLimited weld quality, strength, and aestheticsGood weld quality, strength, and aestheticsHard to masterLow cost of equipment and operationMore spatter and more required cleanupLess cleanup requiredHigh cost of equipment and operationGood at welding thick materialsPoor at welding thin materialsGood at welding a wide range of thin materialsLess able to weld thick materialsVery fast operationSpeed comes at expense of precisionHigh level of precisionSlow

Which Welding Process Should You Choose?

In this section, we look at specific circumstances where a welder may need to choose between MIG versus TIG. Welding TIG vs MIG depends on the size of the project, the base material, the industry, and other factors.

For Beginners and Small-Scale Projects

Beginner welders doing small DIY projects should use MIG welding due to the lower setup costs and easier operation. The higher potential precision and strength of TIG welding is only truly achievable in the hands of an experienced welder.

For Aluminum or Stainless Steel

Hard-to-weld metals like aluminum and stainless steel can be more easily welded through TIG welding due to the lower risk of overheating and burning the material, even in thinner gauges.

For Automotive or Industrial Projects

MIG welding and TIG welding both have applications in automotive and industry. MIG is good for general repairs and high-volume manufacturing, while TIG is good for precision welding of performance parts.

For Precision Work or Aesthetic Finishes

Though slower and more difficult to carry out, TIG welding is far superior for precision work and aesthetic finishes due to the higher level of welder control, resulting in the ability to deposit smaller weld beads.

Applications in Real Life

MIG and TIG welding are widely used across a number of industries to join a variety of metals. Some real-world welding examples are provided below, categorized by sector.

• Automotive: MIG for body panel repair, exhaust fabrication, and chassis brackets; TIG for aluminum intercooler piping and stainless fuel-system components.
• Aerospace: TIG for precision welding of titanium and thin-gauge aluminum aircraft components.
• Shipbuilding: MIG for high-volume hull sections and deck structures; TIG for stainless piping, valves, and corrosion-critical fittings.
• Construction: MIG for steel frames, rebar assemblies, and equipment repairs; TIG for architectural stainless features and specialty handrails.
• Medical: TIG for surgical-grade stainless instruments, implants, and precision tubing.
• Energy: MIG for heavy structural welds; TIG for high-temperature alloys in turbines and chemical-processing lines.
• DIY: MIG for quick, strong welds on mild-steel projects; TIG for custom aluminum parts and motorcycle mods.

Conclusion: Choosing MIG or TIG Welding with 3ERP

Inert and semi-inert gases are key to MIG and TIG, two types of electric arc welding that both have a huge number of useful real-world applications. Their main differences in setup concern the type of electrode and filler material, which has a significant knock-on effect on the difficulty and effectiveness of each process, with TIG requiring more expertise but delivering better results in terms of weld strength and quality. Nonetheless, both arc welding processes are essential skills for a professional welder, giving them a range of approaches for different metals and parts.

3ERP is home to an experienced team of skilled welders and metalworkers. For your metal production and assembly needs, request a quote today.

FAQs

Is TIG welding better than MIG?

TIG welding surpasses MIG in some respects. It can achieve stronger, more precise, and more aesthetic welds, at the expense of greater cost and difficulty.

Is TIG stronger than MIG?

Yes, superior heat control allows for better penetration and stronger welds.

Which one is easier to learn?

MIG is one of the best beginner welder processes, requiring less manual control. It also has lower equipment costs, which may suit beginners.

Which is faster and more efficient, MIG or TIG welding?

Of the two arc welding processes, MIG is faster due to its automatic wire feeding.

Can MIG weld aluminum?

Yes, but the setup is more complicated than it is for a material like mild steel. TIG is better suited to tricky materials like aluminum.

What gas is used in TIG and MIG?

Argon is the most common shielding gas for TIG and MIG, though helium is another common choice. MIG welders may use a semi-inert gas—a combination of a gas like argon with carbon dioxide—for ferrous metal welding.

Which process is best for thin metals?

TIG is much better for thin workpieces thanks to its greater precision.

Which is the best all around welder?

An argument can be made for either process. MIG is faster and simpler, allowing for high-throughput welding. But TIG accommodates a wider variety of materials.

Can both MIG and TIG welding be used outdoors?

Both can be used outdoors, though with some difficulty, especially in windy conditions. Wind disturbs the shielding gas, which can lead to defects. Processes that use flux built into the electrode are better in this regard.