Understanding MIG and TIG welding

MIG and TIG are the two most common welding processes, outside of the more commonly known spot welding. Sharing similarities where both practices use an electric arc and a shielding gas, it is easier to explain their differences.?

Techniques?

MIG welding uses a solid, consumable wire that is machine-fed through the welding gun to the intended weld area. The weld gun emits a shielding gas of 75% argon and 25% carbon dioxide to protect the weld from atmospheric contamination.?

TIG welding uses a non-consumable electrode to bond the metals. Using a hand-held, separate filler rod, the wire is fed as needed to the weld area. Unlike the shielding gas emitted by MIG, TIG releases pure argon to protect the local atmosphere.?

Applications

MIG is mostly used for fast, efficient welding of materials such as steel, stainless steel, and aluminium. It is a preference in welds, such as automotive fabrication, construction, and general manufacturing where speed and productivity are essential.?

TIG is preferred for high-quality and detailed welds with materials like stainless steel, copper, and exotic metals. Most often applied to aerospace, automotive and precision welding where aesthetics can be integral.?

Precision

MIG welds are strong but often they are not as precise or as aesthetically pleasing as TIG.?

TIG welds produces higher quality, more precise results due to the better control overheat input and as a result the reduced distortion and minimal spatter.?

Skill Level

In general, MIG is considered the easier to learn and master of the welding practices. It is the most common and most popular choice for beginners and less experienced welders.?

The challenges that come with TIG welding requires a higher level of skill and dexterity. The multi-tool process requires the welder to control the weld gun, filler rod and foot pedal simultaneously.?

Costs

MIG welding equipment is generally more affordable, easier to obtain and simpler to use, making it the more cost-effective choice for many applications.?

TIG welding equipment is more complex and therefore more expensive. The higher cost is typically down to the advanced controls needed and a higher-quality shielding gas.?

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Which weld do I need?

This summary of key differences will help you quickly find if MIG or TIG welding practices are the most suitable for your project:?

Quickest? MIG?

MIG welders typically provide faster welding speeds of production. This is because air-cooled MIG welders automatically feed filler material into the weld area. This allows welders to move the weld puddle faster and make longer runs without overheating. TIG welders do not get this feature, they cannot move the weld puddle as fast or supply enough filler rod to compete with MIG welding speeds.?

Cheapest? MIG?

TIG welding costs more than MIG welding. This is due to the lower deposition rates associated with TIG as well as the need for more experienced, and thereby more expensive, welders. In addition, TIG welding requires more prep work, which also adds to the cost. Finally, MIG welding supplies and machines tend to be less expensive than TIG. All these factors combine to make TIG welding more expensive than MIG welding.?

Ease? MIG?

MIG welding stands out as a more accessible skill to have and refine compared to TIG welding. Unlike TIG welding, which demands the use of both hands, one for guiding the welding gun and the other for feeding the filler rod into the weld pool, along with a foot pedal to manage amperage, MIG welding simplifies the process. By using just one hand, a welder can complete the weld, making it less intricate.?

Strength? TIG?

TIG welded joins are typically stronger than those produced by MIG welding. This is because the narrow, focused arc created by TIG welders offers better penetration of the metal. Despite this generalisation, MIG welds can still produce strong welds with good penetration by grinding or cutting a V-shaped groove into the joint before starting to weld to increase penetration. Good travel speed and torch positioning will also improve the weld strength of MIG welds.?

Aesthetics? TIG?

TIG welds tend to show better aesthetic qualities than MIG welds. With very little or no spatter, TIG welds usually only require light polishing to finish and remove any discolouration. TIG welded stacks of ‘coins’ are often seen as the most aesthetically pleasing weld and can serve to make unpainted welds look their best. By contrast, MIG welds have a less desirable appearance, even though an experienced welder can still create good-looking MIG weld beads?

Working with thick materials? MIG?

Working with thin materials? TIG?

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Neither MIG or TIG can be considered ‘better’ than the other as they both have their own advantages and disadvantages depending on the situation. Speak to our team today on 01278 558505 to find out which weld could be best for your project.?