MIG and TIG welding are common types of welding that share some similarities. However, they differ in many other welding attributes. These differences result in distinct advantages, downsides, and applications for these welding process. Understanding MIG vs TIG welding differences requires a closer examination of both processes.

Both welding techniques produce high-quality welded joints and efficiently join different materials. However, their unique processes make them suitable for different applications. Choosing the right method requires a thorough comparison of MIG and TIG welding. Let’s explore how these two popular welding methods differ from each other.

MIG vs TIG welding
MIG vs TIG welding

What Is MIG Welding?

MIG welding, also known as Gas Metal Arc Welding (GMAW), uses a consumable electrode and shielding gas to join metal pieces. It is widely used due to its versatility and broad applications.

MIG welding process
MIG welding process

In MIG welding, a welding gun feeds a continuous wire electrode, typically steel, into the weld joint. As the electrode melts, it creates a weld pool that fuses the base metals. The welding gun also releases a shielding gas to protect the weld zone from contaminatio. The gas could be argon or an argon-carbon dioxide mix. An electrical current passes through the electrode, creating an arc that generates intense heat. It melts both the electrode and the base metals. The melted electrode material acts as a filler metal, solidifying to form a strong bond.

MIG welding is known for its high speed, thanks to the continuous electrode feed. It is commonly used in industries like automotive, construction, and manufacturing for joining metals such as steel, aluminum, stainless steel, etc.

What Is TIG Welding?

TIG (Tungsten Inert Gas) welding or GTAW (Gas Tungsten Arc Welding), is a precise and versatile process used mainly for thin sections of aluminum, stainless steel, and other non-ferrous metals. It produces high-quality welds with strong mechanical properties and excellent aesthetics.

TIG welding process
TIG welding process

In the TIG welding process, an electric arc forms between a non-consumable tungsten electrode and the workpiece. Unlike MIG welding, the tungsten electrode does not melt and remains intact throughout the process. The electrode is held in a TIG torch, and an inert shielding gas is continuously released to protect the weld zone from contamination. The shielding gas in this case is typically argon or helium.

To start the arc, the welder touches the tungsten electrode to the workpiece and then quickly withdraws it while maintaining a suitable arc length. The heat generated by the arc melts the workpiece and any filler material (if used), forming a weld pool. If needed, the machinist can manually feed the filler metal into the weld pool.

MIG vs TIG Welding Contrast: Key Differences

To choose the better method for your project, you need to understand their differences. Knowing how MIG and TIG welding differ helps you compare them effectively. Before we examine them in detail, here is a summary of the main differences:

FeatureMIG WeldingTIG Welding
Weld StrengthProduces strong weldsGenerally stronger
Weld SpeedFaster, ideal for high productionSlower, requires more time and skill
Power SourceUses DC with a constant voltage characteristicUses AC or DC depending on metal type
Electrodes UsedConsumable electrodes that act as fillersNon-consumable electrodes with a separate filler rod
Welding GasArgon-CO2 blend (75% argon, 25% CO2)Pure argon; argon blends with helium, nitrogen, or hydrogen
Cooling SystemTypically uses air-cooled torches, water-cooled optional for high heatOften uses water-cooled torches due to higher heat generation
Weld AppearanceProduces good welds; not always critical for appearanceCreates clean, aesthetically pleasing welds, ideal for visible workpieces
Weldable MetalsSuitable for thicker metals; high production ratesBetter for thin metals; precise control reduces warping and burn-throughs
CostLower initial cost, faster process reduces cost per foot of beadHigher initial cost, slower process increases cost per foot of bead

Table of differences between MIG vs TIG welding

Weld Strength

TIG welded joints are generally considered stronger than MIG welds due to the narrow, focused arc that penetrates the metal better. Properly done TIG welds are clean and usually have few welding defects. Therefore, many experts believe that TIG welds are stronger based on their penetration level and minimal defects.

However, this view might be a generalization. Both methods can produce strong and durable welds. You can also enhance MIG weld strength and penetration by cutting or grinding a V groove into the joint before welding. Maintaining a good travel speed and torch position is another recommended practice. In terms of weld quality, TIG welding often provides a cleaner, more aesthetically pleasing finish. Thus, it is often preferable for applications requiring high visual appeal.

Weld Speed

For production, MIG welders offer better speed. While TIG welding produces clean and attractive welds, it is slower. TIG welders cannot move the weld puddle or supply filler rod as quickly as MIG welders. During lengthy welds, air-cooled TIG torches can overheat. This may require a switch to more expensive and complex water-cooled torches.

In contrast, MIG welders automatically feed the electrode or filler material, and their broader arc dissipates heat better. These features allow welders to move the weld puddle faster and make longer runs with an air-cooled torch. Larger operations prefer welding units that can run for long periods and create continuous weld beads. Therefore, quality MIG welders are often the choice for industrial shops needing high production.

Power Source

TIG welding uses AC or DC power sources. This depends on the metal and the desired arc type. AC power is better for aluminum because it cleans the oxide from the metal surface. In contrast, DC power is used for creating strong electric arcs. In a standard MIG welder, the relationship between welding current and voltage is known as a flat or constant voltage characteristic. The power source converts the mains supply to a usable welding supply, producing a DC output. 

Electrodes Used

Electrodes conduct electricity, create electric arcs, or act as fillers. There are two types of electrodes in electric arc welding: consumable and non-consumable. Both create electric arcs, but consumable electrodes also serve as fillers and are consumed during welding. The MIG welding process uses consumable electrodes, while TIG welding uses non-consumable electrodes. Examples of consumable electrodes include nickel steel and mild steel. Non-consumable electrodes include tungsten, graphite, and copper-coated carbon.

Shielding Gas

Welding gas for welding
Welding gas for welding

A shielding gas protects the weld puddle from reactive gases in the air, preventing impurities that can compromise weld quality. TIG welding typically uses pure argon gas because the tungsten electrode is quite sensitive to reactive gases like oxygen and CO2. The flow rate is usually 15 to 25 cubic feet per hour. For special applications, TIG may use a mix of argon with nitrogen, helium, or hydrogen.

MIG welding often uses a blend of argon and carbon dioxide (i.e., 75 percent argon, 25 percent CO2). The CO2 component enhances arc stability and penetration. In this case, the required flow rate is 35 to 50 cubic feet per hour. For specific applications, such as MIG welding aluminum, pure argon is often required. Pure CO2 can also be used in MIG welding. It offers cost savings and increased penetration despite some disadvantages.

Cooling System for Welding Torch

A welding torch generates a lot of heat and needs proper cooling. Water and gas are two popular coolants used in welding. Air cooling is light and inexpensive but less effective for very high temperatures. Water cooling is often more efficient than air cooling. Since TIG welding generates more heat than MIG welding, it often uses water-cooled torches. However, air-cooled torches can be used for both processes.

Weld Aesthetics

Properly created TIG weld beads are clean and professional. They create minimal spatter and usually require only light polishing. The neat “stacked dimes” left on TIG welds are often considered the standard for aesthetically pleasing welds. Thus, TIG welding has an advantage over MIG welds in appearance. In situations where the piece is not coated or painted, such as with aluminum and stainless steel, TIG beads are preferred to enhance the finished piece’s visual appeal.

Aesthetics in welding
Aesthetics in welding

However, this doesn’t mean that MIG welds are unattractive. Experienced welders can produce visually appealing beads with a MIG welder. For many projects, a flawless weld appearance may not be necessary. Additionally, since steel welds are often painted or coated, the weld appearance is less critical. Moreover, MIG welding is commonly used for steel intended for painting.

Weldable Metals

The thickness of the material is a crucial factor in choosing between these two methods. TIG welding is more suitable for thick metals due to its better operational control, which reduces the risk of damaging the workpiece.

Metals for various welding techniques
Metals for various welding techniques

For stainless steel, which retains heat efficiently and is prone to warping and distortion, TIG welding offers precise heat control through a foot pedal. This results iin better weld control and precise welds, making it the preferred method for most stainless steel welding applications. However, there are instances where MIG welding stainless steel with a pulsed current may be preferable. It is often preferred for high production rates, complex joints, and out-of-position welding.

Welding aluminum presents its own challenges due to its high heat conductivity and the rapid formation of aluminum oxide, which disrupts the arc. TIG welding  is often preferred for welding aluminum. It offers precise heat control and alternating current (AC) capability, which better cleans the aluminum oxide layer. 

While MIG welding of aluminum is feasible, it requires thorough cleaning and preparation of the metal. It also demands careful handling of the soft aluminum wire to avoid issues like contamination and wire feeding problems. Despite these challenges, MIG welding can offer higher productivity once proper precautions are in place.

Cost

TIG welding tends to have a higher cost per foot of bead due to its slower nature and lower deposition rates. It often requires more time and skill from an experienced welder. Additionally, the initial cost of a TIG welder is typically higher, and consumables may be slightly more expensive.

On the other hand, MIG welding units generally have lower initial costs and faster welding speeds, resulting in a lower cost per foot of installed bead. Moreover, MIG welding requires less preparation work compared to TIG welding.

Pros and Cons of MIG and TIG Welding

Before making a decision on which welding technique to use, examine the benfits and drawbacks of both TIG and MIG welding for your project. This will help you select the appropriate method but will also enhance your welding skills overall.

MIG Welding

Pros

  • The welding time is faster.
  • Welding equipment is less expensive. 
  • Materials are usually readily available.
  • Creates strong welds easily and accurately.
  • The process can be automatic or semi-automatic.
  • Enables welding at difficult angles.

Cons

  • Welds are not usually as strong as welds from TIG.
  • It is often more challenging to control weld beads.
  • Not suitable for welding thin metals.
  • The process may create potentially harmful fumes and smoke.
  • Unstable electric arc.

TIG Welding

Pros

  • Creates higher quality welded joints. 
  • Using filler materials is optional.
  • Greater precision and accuracy from the foot pedal.
  • It is an environmentally friendly process.
  • It is a versatile process, compatible with several materials.
  • Better operator control.
  • Lesser operation and maintenance cost due to the use of non-consumable electrodes.

Cons

  • The welding process is relatively slower than MIG
  • Requires clean metal surfaces for welding.
  • Needs operator experience and expertise for high-quality welds.
  • Relatively more expensive than MIG welding.

Applications of MIG and TIG Welding

Choosing either welding techniques for your projects demand careful considerations of where each process is useful. Here are some application of both processes.

Applications of MIG and TIG welding
Applications of MIG and TIG welding

MIG Welding Applications

Here are some instances where MIG welding is highly useful:

  • Welding Thick Metal Stock: MIG welding uses a consumable electrode that acts as a filler and solidifies the weld. This method is faster and more efficient for welding thick metals. The continuous wire feed is more productive than the hand-fed rod used in TIG welding for supplying the necessary filler material.
  • Welding Low-defect Components: It operates continuously, unlike the start-and-stop nature of TIG Welding. This reduces the likelihood of welding defects, making MIG welding ideal for producing low-defect products.
  • Longer Production Runs: This sheet metal welding technique is efficient and easy to manage, making it ideal for long production runs. Its continuously fed wire handles lengthy tasks effectively. 

TIG Welding Applications

This welding technique will be better in the following situations:

  • Welding Thin Metal Sheets: TIG welding offers better control, making it highly precise and accurate. This makes it ideal for welding thin metals, which are prone to warping and burn-through.
  • Welding Aluminum Components: Aluminum, titanium, and copper are thin sheet metals that need an aesthetic finish without compromising functionality. TIG welding’s precision and quality joints make it the best choice for welding these metals.
  • Shorter Production Runs: TIG welding is ideal for short production runs due to its precision. However, it becomes more complex and costly for long production runs.
  • Handling Delicate or Fine Works: It is also preferred for projects where appearance matters, such as automotive restoration, sinks, artworks, etc. It is ideal for highly visible pieces and provides the heat control needed to prevent warping and burning.

Conclusion

Experts often debate the merits of MIG vs. TIG welding, as both have their pros and cons. Neither is definitively “better” than the other; the choice depends on the project. MIG welding is generally faster and ideal for large production runs, while TIG welding produces higher quality welds, though exceptions exist.

When choosing a welding method, consider factors like quantity, material type, cost, and post-processing needs. If you’re unsure whether to choose MIG or TIG welding, ZINTILON can help. We specialize in sheet metal welding and several other machining services. Our team will work with you to find the best solution for your project,. Get a free quote today.

FAQs

What is the primary difference between TIG and MIG welding?

The primary difference between MIG and TIG welding lies in their application and principles. MIG welding is better for thick metals, while TIG welding excels with thin metals due to its precise operational control. MIG welding uses a consumable electrode that serves as a filler, whereas TIG welding employs a separate filler rod.

Is TIG or MIG the best option for welding aluminum?

TIG welding is often more preferable for aluminum because the metal is a lightweight material that demands precise operational control. Additionally, aluminum is often chosen for its aesthetic appeal. TIG welding’s high-quality welds make it the preferred option.

Which should I choose between welding and riveting?

Welding and riveting are distinct joining methods, each with its own benefits and downsides. Riveting is temporary, while welding creates permanent bonds. Additionally, welding typically offers less aesthetic appeal compared to riveting. So, you have to weigh these factors when deciding between the two processes.

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