Expert Guides

MIG Welding vs TIG: The Key Differences

Do you know which weld technique is most effective for your product? 

A wide range of metallic materials can be welded, including stainless steel, steel, aluminium, titanium, copper and nickel. These materials can be welded by several methods, including Metal Inert Gas welding or Tungsten Inert Gas welding, also known as MIG and TIG, which are two of the most common weld techniques.

MIG and TIG Welding

Whilst there are several similarities between the two, they are different methods and excel in different applications. Understanding the differences between MIG and TIG welding is central to choosing the right weld method for your product.

Wrekin Sheetmetal offers both TIG and MIG welding, and can help you determine the most appropriate weld technique for your product.

Let's delve deeper into the pros and cons of each technique and discover which one suits your needs.

MIG Welding

Used to join two pieces of metal together, forming a strong weld seam, MIG welding is a common welding method for metals such as steel, aluminium, copper and nickel.

Definition of MIG Welding

Metal Inert Gas welding is an arc welding process which involves the use of a continuous consumable wire electrode, meaning the wire is continuously fed through the welding gun. The electrode is melted when an electric arc is created between itself and the workpiece, forming the weld.

In MIG welding, a MIG torch or welding gun is used, alongside an automatic or semi-automatic wire feeder, power source and grounding cable, and a shielding gas tank.

MIG Welding Process

For a more in-depth look at how a MIG weld is created, we examine the MIG welding process.

During the MIG welding process, a continuous wire electrode acts as an anode whilst the workpiece acts as a cathode; this creates a short circuit and produces an electrical arc between the two materials, heating and melting the wire electrode. In MIG welding, the wire serves as both the heat source and the filler metal for the welding joint.

To protect the weld pool from contaminants, a shielding gas is fed alongside the electrode. This gas, which can be argon, oxygen, or carbon dioxide, depending on the metals being welded, forms an arc plasma, stabilises the arc roots, and ensures a smooth metal transfer.

MIG welding offers different metal transfer modes, including short-circuiting, droplet/spray, and pulsed, allowing for versatility in the welding process.

Pros and Cons of MIG Welding

MIG welding is a fast and relatively straightforward weld method, making it advantageous in many applications.

  • High welding speed. MIG welding offers a high welding speed thanks to continuous wire feed, allowing you to complete projects quickly and efficiently. This makes it a great option for projects with a demanding timescale.
  • Easy to learn and use for beginners. MIG welding is relatively easy to learn and use, making it a popular choice for beginners or those with limited welding experience.
  • Quality weld. MIG welding produces a high-quality and clean weld, with minimal slag and reduced weld splattering.

However, there are some disadvantages to MIG welding, including…

  • Limited in certain materials and positions. The nature of MIG welding means it is not suitable for tricky precision projects such as vertical or overhead welding.
  • Unsuitable for thick metals over 25mm. MIG welding is not recommended for thick metals over 25mm , as it may struggle to penetrate and create a strong bond.
  • Regular maintenance is important. Regular maintenance is also necessary to ensure the equipment functions properly and delivers consistent results. However, regular maintenance will not impact the manufacturing of your product, as machine maintenance is scheduled to avoid unexpected downtime.

TIG Welding

Tungsten Inert Gas Welding is another popular weld method for metals such as steel, aluminium, titanium, brass and more.

Definition of TIG Welding

Unlike MIG, TIG welding utilises a non-consumable tungsten electrode to create precise and aesthetically pleasing welds. This welding process is often preferred for thinner materials or delicate jobs due to its high accuracy and aesthetic quality.

TIG welding requires the use of two hands and often a foot pedal for amperage control. The non-consumable tungsten electrode creates an electric arc that produces intense heat to melt the base metal while a separate filler rod is used to add material to the weld.

The equipment used in TIG welding also varies slightly from MIG – for starters, a wire feeder is not required to feed filler material. Equipment includes a welding torch, power source and grounding cable, and shielding gas tank.

TIG Welding Process

The TIG welding process works similarly to the MIG process – however there are some key differences to be explored.

TIG welding uses electricity to create an arc between a non-consumable tungsten electrode (the anode) and the metal being welded (the cathode). Unlike MIG welding, the tungsten electrode in TIG welding doesn't melt during the process. Instead, the arc melts the parent metal and a separate welding rod of filler metal, forming the weld bead.

The molten weld pool is protected by an inert shielding gas, typically argon or an argon mixture. To perform TIG welding, you need to coordinate the hand-held TIG torch with a filler rod, maintain the correct distance from the weld, and adjust the current, making it a complex process.

Pros and Cons of TIG Welding

Applications, where TIG welding may be chosen over MIG, are likely to prioritise:

  • Precise and high quality welds. TIG welding offers precise and high-quality welds which are incredibly strong, making it ideal for jobs that require greater accuracy, aesthetic appeal and durability.
  • Versatile for various materials and positions. It is also versatile and can be used on various materials (including refractory metals) and material thicknesses, as well as in different positions, allowing for in-situ joining.

However, there are some of the downfalls associated with TIG welding including:

  • Time consuming and requires skill. TIG welding can be time-consuming due to the complexity of the process and requires a high level of skill and experience to perform. At Wrekin Sheetmetal, we continually invest in our team to ensure they have the skills they need to perform at the highest standard – so much so, we launched our own upskilling programme!
  • Higher set up costs compared to MIG welding. The setup costs for TIG welding are higher compared to MIG welding, which can be a drawback for some.

MIG vs TIG Welding: The Key Differences

So, what are the key differences between MIG and TIG welding? Why would you choose one over the other?

When it comes to TIG and MIG welding, there are several notable differences. Firstly, TIG welding uses a non-consumable tungsten electrode and a separate filler rod, while MIG welding utilises a continuously-fed electrode wire and shielding gas. Because of this, the welding technique used for each method is also different.

This leads to another difference, which lies in the skill level required, as MIG welding is generally easier to learn and master compared to TIG welding, which demands more skill and experience.

In terms of cost, MIG welding machines and supplies are generally less expensive, but TIG welding costs more per foot of bead due to the additional prep work involved.

Additionally, TIG welding offers greater weld strength and better aesthetics, while MIG welding is faster and allows for longer runs to be completed in less time. TIG welding is also suitable for a wide range of materials, especially refractory materials which cannot be welded by MIG.

Ultimately, the choice between TIG and MIG welding depends on the specific project requirements, such as material, precision, weld position, project timescale, and more.

In conclusion, when it comes to choosing between MIG and TIG welding, it all depends on the specific needs of your project. Understanding the differences between MIG and TIG is the first step in deciding between welding methods.

Wrekin Sheetmetal’s expert welding team is on hand to offer our customers the advice they need to make the right decision for their fabrication project. We offer MIG and TIG welding, get in touch now by filling out the contact form.

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