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Welding jargon is only confusing until you understand it. MIG and TIG, Heliarc, torch, stinger and electrode are only some of the welding terms I’m asked to clarify every day. This is the nutshell version of the “MIG vs TIG” core debate.
These terms (MIG and TIG) describe:
- Electrode type
- Shielding type
MIG to TIG COMPARISON
MIG welding (Metal, Inert Gas) features a metal wire electrode on a reel, motor-fed to the arc through a hollow cable, paired with an inert gas hose. Strike an arc, and the electrode wire feeds into the puddle, while inert gas shields the process.
If needed, MIG machines can strike an arc with one hand, by triggering the torch. It’s the cheaper of the two processes, for a variety of reasons. It also requires less operator experience than TIG.
- Automated feed
- Continuous electrode
- One-hand operation
- Less cost
- Easier to learn
TIG welding (Tungsten, Inert Gas) uses a sharpened tungsten rod as the electrode. The filler metal is in a rod or bar, fed into the puddle with the off hand, like oxyacetylene welding. The TIG torch also floods the weld puddle with inert shielding gas, like MIG does.
TIG is a craft process, requiring lots of practice, knowledge and a good selection of filler rods. These are more factors that drive costs higher.
The best TIG machines offer finer weld bead control than other types of welders do. There are a quite a few arc adjustments and process controls available, including many you may never use.
Some of these adjustments are intended for exotic materials such as titanium, others for special uses like aerospace, racing or engineering.
- Fixed tungsten electrode
- Two-hand operation
- More costly labor and machine
- More difficult to learn
- Used with exotic metals
- Amperage, pulse rate, sine curve adjustments
For more knowledge about these basic welding terms, check out our Beginner’s Guide to Welding. It’s a great resource for learning the ropes.
Summary of the MIG and TIG Processes
|Electrode||metal wire||tungsten rod||MIG is wire feed. TIG isn’t.|
|Filler Metal||steel, SS, aluminum, cast iron||aluminum, copper, steel, SS, titanium, non-ferrous metals||TIG is common for exotic metals in aircraft, bicycles and racing|
|Shielding Gas||Argon+CO², pure CO²||Argon, helium, nitrogen||Each can vary somewhat by job|
|Adjustments||WFS, Pulse, flow rate||Many Options||TIG is more adjustable, MIG is easier to control.|
MIG vs. TIG Overview
Although MIG is the most common name you’ll hear for it, that’s actually an outdated term. The American Welding Society updated these terms to include the class of material being worked.
The AWS prefers Gas Metal Arc Welding (GMAW) these days, to describe the overall combination of shielding, material and class of welding (either arc or gas welding.) If you’re confused by the terms “gas shielding” and “gas welding,” refer to your free Beginner’s Guide to Welding.
MIG is a wire-feed process, meaning the wire electrode is fed automatically from a spool inside the welder cabinet. In some high-production industrial work, the spool of electrode wire and its electric feed motor are entirely separate cabinets from the welding machines. Bigger spools and stronger motors are the reason for separate cabinets.
You’ll hear the terms “flux-core” or “wire feed” used pretty often around MIG discussions. These terms refer to a modified MIG process called gasless MIG, or flux-core welding. It’s mainly distinguished by the lack of bottled shielding gas and its delivery hose. For this discussion, we’re talking about the complete, bottled-gas MIG process.
The MIG electrode is a spool of solid wire. The diameter of the wire and its composition depend on the metal being welded. Factors such as material thickness, carbon level in steel, or hardness of aluminum affect electrode wire choices. So does what type of joint you’re making and the speed the wire is feeding into the arc, known as Wire Feed Speed, or the WFS setting.
As the wire feeds into the process, it’s consumed as filler metal, mingling into the weld puddle. Because it becomes part of the work piece, the right electrode choice is very important, and so is your WFS rate.
WFS will affect the amount of filler metal flowing into the weld, the temperature of the weld process, and in cases where you’re working near the welding machine power limits, wire speed can affect the amount of electric current that’s available at the weld joint.
Larger or smaller wire spool sizes are another thing to consider when choosing wire feed speed. Many MIG machines automate the choice of WFS based on settings for material thickness and the amperage setting.
Like MIG, the American Welding Society updated the process name for Tungsten Inert Gas (TIG) to Gas Tungsten Arc Welding (GTAW.) Also like MIG, just about everybody still calls it TIG. Welders still use these terms because they’re traditional, as well as short.
GTAW refers to the fact that this is an electric arc-based process. The electrode that creates the arc at the fusion point is the primary difference between the TIG welder and a MIG machine. With TIG welding, the electrode is a rod made of tungsten, rather than a wire feed like MIG or a filler rod that’s consumed in the process, like stick welding uses.
With TIG welding, the filler comes from a long rod or bar, chosen with the right size and composition for the material and heat level in the job. The operator feeds the filler rod into the weld puddle with the free hand, like oxyacetylene welding, requiring a great deal of skill.
This manual craft aspect of TIG welding means that it’s usually done by people with a lot of experience. Of course, welders with this level of skill tend to make more money, adding to the cost of the process. It can be very difficult and slow, but in the right hands, produces fine-quality results like no other welding process.
The TIG electrode is sharpened to a fine point, providing precision heat control, adjustments for bead width, the ability to clean oxidation out of the weld puddle and fine-tune welding performance. The electrode is not consumed as part of the weld, although it does wear during the work and will need sharpening and eventual replacement.
TIG shielding gas is usually pure Argon, avoiding contamination of the weld by tungsten oxide from chemical reactions between the tungsten electrode and CO² shielding gas. Helium has also been used in the past, which is why this process was originally called Heli-Arc, and sometimes still is by old-timers.
Most of the time, TIG welding machines have adjustable heat control, allowing the operator precise control over heat levels at the weld. This is one reason for TIG welding’s reputation for superior quality. The heat control can be a thumbwheel, a rheostat device or a foot pedal that regulates the amount of current at the arc site.
For more information about TIG welding, make sure to read my GTAW welding guide.
MIG and TIG technology developed quite rapidly over the last two decades, with a lot of choices that improve your welding skill and performance.
Some additional capabilities like multi-process machines, better torches, wire feeders, and on-screen instructions are probably worth the money.
It’s always worth researching in depth for the best MIG welder to suit your needs. Today’s MIG machines make for better beginners, but also offer advanced options for advanced welders.
Some advanced MIG features to watch for include:
- Automated setup – based on material and thickness
- On-screen manual – some have lists of settings
- Multi-process welding – Include other types of welding
- Spot weld timer – Small, short bursts that weld overlapping panel seams
- Dual voltage power – Use either 120v or 240v power
- Settings memory – Saves a variety of pre-programmed settings for later recall
The best TIG welder values are those that offer a wide range of adjustments and convenience features at reasonable cost. Like the MIG machines, there has been a lot of technology improvement in the last 20 years.
Look for these important TIG features:
- No-touch arc starting – Avoid tungsten electrode contamination by not touching the surface, arc will strike when the torch is close to the surface
- AC and DC TIG welding – Allows working with a wider variety of materials
- Phase Adjustments – AC Balance cleans the weld surface, stirs the weld puddle and releases contamination by modifying the AC cycle. The positive cycle cleans oxidation off the surface. The negative cycle penetrates the metal, lifting impurities out of the weld puddle
- 2T/4T Trigger Lock – Enables long, continuous seam welds like automobile or trailer floors
- Pulse Width Modulation – Provides detailed control over weld bead characteristics, such as width, by setting the rate of current pulses per second, low frequency for a narrow bead or a higher rate for a wider bead
MIG vs TIG: Welding Performance Comparison
Despite similar names and the superficially similar appearance of the welding equipment, the MIG and TIG welding processes are actually very different. Each has substantial advantages, depending on work requirements. Each can have significant drawbacks.
Neither process solves every problem with cost, craftsmanship or production speed. Simple comparisons of cost or speed don’t always uncover the true reasons for choosing one process over the other.
Examining detailed factors such as operator time, craftsmanship level, material needs and finished product requirements is the best way to choose which welding process to use.
Evaluating weld strength isn’t a direct comparison between welding methods. The fusion of workpiece metal, filler metal, temperature, weld puddle flow, and depth of arc penetration all have a piece of the action.
Weld strength is also dependent on other variables, such as material thickness and how long a time the workpiece spent at or near welding temperatures. Heating or cooling too quickly, metal impurity and weld porosity weaken joint strength.
Without actual mechanical testing, anyone comparing weld strength by educated guess will need to consider these criteria.
MIG Weld Strength
In general, MIG welding penetrates very well, and because it’s easier to concentrate on the MIG’s highly visible weld puddle when you don’t have to manage a filler rod, it’s easier to get quality results.
The reason I say “In general” here is that MIG is outstanding at materials ranging from thick sheet metal up to about 3/8-inch thick, but really isn’t suited for big, thick plate or pipe. Experienced welders can get great results up to maybe 1/2-inch thick or even more, often grinding bevels, using fitted cuts and grooving joints to get the penetration needed.
However, 3/8-inch thick material is pretty substantial, good enough for car frames and equipment mounting brackets. MIG works extremely well on the material sizes that are most often used for fabrication and repair. It’s holding up to thousands of daily uses by millions of people around the globe as you read this.
A lot of these differences are a matter of degree. MIG welding with E70 electrode wire, welding with a TIG filler rod or stick welding with an electrode that are rated at 70,000 psi tensile strength are all processes that are potentially the same strength. The difference is operator skill and knowledge.
The main weak point of MIG strength actually comes from one of its advantages. Because it doesn’t leave any slag on top of the bead, MIG welds can cool too quickly, potentially contributing to brittleness.
TIG Weld Strength
Industry authorities often mention general trends of behavior with given materials and process cases. For instance, a TIG arc runs at higher temperatures, but its ability to precisely control heat input means that it’s well suited for thin sheet metal at low current levels.
However, despite its higher cost, experience, and labor time, manufacturers and custom engineering shops prefer TIG for jobs where weld strength is the main deciding factor.
TIG is the choice for:
madewith stout sizes of chromoly, stainless steel, aluminum and titanium.
Even so, that doesn’t put the MIG vs TIG argument to bed automatically. Because TIG depends so heavily on craftsmanship in small production, there’s still a lot of potential variation in quality between individuals doing the welding.
Manufacturers offset the quality and consistency question on the factory floor with automation and standardized procedures.
MIG is my favorite process, but because industry chooses TIG when strength matters most, and gets repeatable results, I’m going with the “TIG is stronger” answer.
MIG welding offers the best speed for production processes, hands down. One-handed operation, easy adaptability to automation, adjustable wire feed speed, and the continuous electrode put MIG way out in front.
TIG welding is concerned with high quality weld production, above all else. Production speed isn’t even a priority. It’s just not possible for a TIG operator to push the weld puddle and feed the filler by hand as fast as a MIG machine can feed wire into the weld.
Without having to juggle tasks for both hands, less heat in the work piece with a bigger, rounder arc and no need to stop welding to grab another filler rod, MIG welders are the fastest way to weld, both manually and on automated production lines.
Inexpensive costs and better cooling of the MIG process make it invaluable in volume production.
Both MIG and TIG processes depend on shrouding gas to shield the weld puddle from contamination and oxidation. The gas is delivered at the torch tip whenever the arc is struck to ensure a high-quality weld.
However, each process uses different shielding gases. When TIG welding, which uses a tungsten electrode, you’ve got to take pains not to contaminate that piece of tungsten.
CO² will react with tungsten, and causes weld defects. That means standard argon/CO² MIG shielding gas can’t be used for TIG welding. TIG usually uses pure argon, while MIG machines commonly use a 75/25 mix of argon and CO².
At times, a TIG machine might need a shielding gas blend of helium, nitrogen or other gases with argon for exotic metals like titanium.
MIG gas makeup does change for certain applications. When MIG welding aluminum, 100% argon or pure CO² are frequent choices.
It’s important to set your gas flow rate to keep down costs without compromising your weld quality.
It’s common to see a MIG welder flowing 35 to 50 cubic feet per hour, while TIG welding commonly needs the shielding gas flow set to 15 to 25 cubic feet per hour.
Aesthetics: MIG vs TIG
For exposed joints like motorcycle and hot rod frames, architectural design elements or signs, naked TIG weld beads have been an industrial standard for decades. The neat, orderly “stack of dimes” appearance of a proper TIG weld reassures the eye that everything is in its place. This is especially true on polished, unpainted structures.
Without the same spatter issues suffered by MIG users, TIG welders can clean up and move to the next weld faster than a MIG operator can. This really isn’t a big issue, but it’s true that MIG needs more touching with the grinder than TIG does.
If the workpiece is painted or has a utility use, it might not matter at all. A good MIG operator will have the heat and WFS set to produce beautiful, crafted welds anyway.
Fine or Delicate Welding
When the final piece must look great, TIG is often the go-to welding method. Pieces like artwork, automotive restoration, sinks, etc., that are highly visible are prime TIG applications. Plus, you have the heat control needed to prevent warping and burning with thinner, finer pieces of metal.
Related: What Can You Weld With a TIG Welder?
Metals Welded by MIG and TIG
These are two very versatile welding processes. Together, in skilled hands they can build just about anything. That’s because between them, MIG and TIG can weld just about anything.
Non-Ferrous Metals: MIG and TIG
For metals other than carbon steels,
- Stainless steel
- Other exotic metals
The choice is usually TIG, but not always. MIG works great for aluminum, within limits. Robotic welding processes use either, depending on what they’re building.
MIG vs TIG on Aluminum
The single biggest factor for properly welding aluminum is that it heats quickly, but also cools quickly. Heat management is critical.
Experienced MIG welders manage heat well, through best practices, material choices, proper settings and alert, intentional welding.
Heat management is already part of the TIG process. The operator is precisely and accurately controlling localized heat conditions in real time. It’s a great process for building with aluminum, but it’s not as fast as MIG.
The next important factor with aluminum is the welding surface itself. Aluminum oxide forms a thin dull, gray or white crust on the surface, slowing current flow, adding to local heat by more electrical resistance.
In addition, this film produces particles and fumes, contaminating the weld puddle. With a TIG machine, there’s a possibility of contaminating the tungsten electrode.
However, TIG machines offer AC cycle adjustments such as AC Balance. Modifying the AC cycle enables cleaning the weld surface, stirs the weld puddle and avoids contamination.
The positive cycle cleans oxidation off the surface. The negative cycle penetrates the metal, bringing impurities in the weld puddle to the surface.
Welding aluminum with MIG machines takes a little preparation and a lot of paying attention to the heat in the piece. The MIG weld puddle is more vulnerable to contamination than TIG, meaning it has to be cleaned well for best results.
The wire electrode needs to be clean, dry of oil or wax and the right filler material to match the work piece. Using new wire is best. A spool gun is optional for MIG, but you really do need the best MIG spool gun for aluminum that you can find.
Because aluminum electrode wire is soft, it bends and kinks up easily when the wire fed mechanism pushes it through the welding lead to the MIG torch.
A spool gun solves this problem with a torch attachment that puts a small wire feeder spool right on the MIG gun itself. Instead of trying to feed the wire six feet or more inside the lead, the spool gun shortens the feed distance to under a foot.
With a little practice and the right tricks, welding aluminum with MIG is easy and productive. TIG offers far more control and potentially higher quality, but at the cost of lower production speed.
Weld Copper with MIG and TIG
Copper conducts heat even better than aluminum, meaning there’s more current needed at the weld site as the heat bleeds off.
The usual MIG method for fusing copper is brazing, using silicon bronze wire in a spool gun. The silicon bronze filler metal melts at a lower temperature than copper does, reducing chances of blowing through on thin metal.
However, if you need to truly weld sections of copper together, especially thin sheet metal and vessels for brewing or distillery, DC TIG is really the only answer. Precise heat control, combined with the ability to weld at much lower current levels (because of a hotter arc) mean TIG is tailor-made for this kind of work.
Because of its high thermal conductivity, copper demands heat levels nearly twice what steel needs. When working with thicker sections like pipe or electrical termination points, preheating is going to be necessary.
MIG and TIG: Welding Magnesium
Magnesium is very light, aids in dampening vibration, and it’s easily machined. These are the main reasons magnesium is one of the primary choices in racing, for wheels, pully assemblies and chassis mounting points.
Magnesium has a similar appearance to aluminum, and it’s important to make sure what you’re working on.
Another issue is the relatively narrow temperature range between the melting (welding) point at 650 degrees F and its auto-ignition point at around 800 degrees F for small pieces and airborne particles.
Grinding, welding and machining magnesium takes careful attention!
MIG welding magnesium is feasible with a spool gun, but magnesium wire for MIG is hard to get and extremely expensive. TIG filler rods for magnesium come in short lengths for cost control.
This expense, and the clear need for precision heat control, mean TIG is the usual choice for magnesium.
MIG or TIG for Stainless Steel?
The main challenge for welders tackling stainless steel is a high degree of heat retention. Like any metal, the more you weld and grind, the hotter it gets, and stainless steel stays hot for a long time.
It’s easy to spike the temperature to a point where the work piece will deform slightly as the temperature finally starts cooling off. TIG is often the go-to choice because of heat control, exposed welds and strength ratings.
That’s great if you can run a TIG machine, but if not, what then? Fortunately, there’s a lot of stainless out there, and a lot of MIG machines ready to run beads on SS using pulsed current settings.
Stainless electrode wire is readily available. Another reason for MIG on stainless is the physical exertion needed when TIG welding out of position. The single biggest reason is probably the higher production rate for MIG welding in a factory setting.
MIG vs TIG for Titanium Welding
Titanium welding needs specific, detailed precautions for proper fusion. However, it’s not necessarily harder to weld, in a technical sense, than other advanced materials such as aluminum or magnesium.
Because it’s extremely reactive to oxygen, the titanium weld puddle needs total shielding from air. It used to be done mostly in sealed portable chambers, and often still is. In recent years, industry pros have developed ways to weld titanium, with both MIG and TIG, in the fabrication shop. Auxiliary shielding gas, preflow and postflow features keep the weld puddle shielded from atmosphere until weld temperatures drop under 800 degrees F.
Preparation and techniques like those for nickel alloys and stainless steel are similar for titanium, but Ti takes a lot more attention to detail when it comes to cleanliness.
The American Welding Society recommends cleaning before, during and after the work, for both the material and the filler metal, using either acetone or methyl ethyl ketone (MEK.) Acetone is highly flammable and MEK fumes are toxic. Titanium dust from grinding can auto-ignite.
Details matter in regards to safety.
AWS recommends metal thicker than 4mm for MIG welding titanium, and pulsed current is the only way to get proper fusion. In addition, the electrode should be cleaned often during the process.
DC TIG is the preferred method for welding titanium, especially with thin sheet material. Electrode choice is limited to DC-compatible cerium tungsten types, and you want high-frequency, no touch arc starting to avoid chances of contaminating the electrode or the weld.
Learning MIG or TIG
There’s really no dispute in the welding community on the question of which process is easier to learn. TIG is widely considered the most difficult process to master, requiring of you:
- Meticulous cleaning
- Proper shielding gas and flow rate
- Excellent motor skills
- Operate the torch without touching the surface
- Chase and feed the weld puddle with filler rod
- Run heat control such as a pedal
- Manage settings on the fly
- Superior concentration
- Obsessive attention to detail
While the main concerns with MIG are:
- Current and polarity settings
- Wire Feed Speed
- Spool tension
- Smooth feeding
- Proper shielding gas and flow rate
- Ability to steady your torch hand
The fact is, welding isn’t a quickie skill. It’s a craft process that takes years to master. Even though the basics aren’t hard to learn, you’ll spend the rest of your life perfecting your craft, no matter what process you choose to follow.
MIG offers clear advantages over TIG in the faster learning curve (hours vs weeks,) easier surface prep, easier machine settings, easier maintenance, easier cost and faster, earlier production rates.
If you want to get up and running beads quickly, MIG and Flux Core Welding are your best options, stick close behind. TIG is an advanced craft process for advanced welders, not a beginner’s learning path.
MIG Cost vs TIG Cost
With more complex and expensive equipment, more knowledge and experience needed (translation: higher payday,) more time spent in preparing the weld, and more time welding to cover the same distance, TIG welding runs significant costs above the MIG process.
The volume nature of a continuous wire feed electrode reduces MIG costs even more over the long haul. MIG welding offers clear cost advantages over TIG, while providing versatility and ease of use to DIY crafters and professional welders alike.
MIG vs TIG: Summary Table
|Weld Strength||Penetration||Heat control||Industry chooses TIG|
|Welding Speed||Auto wire feed||No speed advantage||TIG is much slower|
|Shielding Gas||75/25% Argon/CO²||100% Argon||Both vary by job|
|Aesthetics||Needs finish work||Neat appearance||MIG for paint
TIG for polish
|Aluminum||Needs cleaning||Cleans the weld puddle||MIG uses spool gun
TIG is prettier
|Copper||Silicon bronze wire||DC TIG||MIG uses brazing|
|Magnesium||Wire is extremely expensive||Precise heat control||Magnesium electrode MIG wire over $200/pound|
|Stainless Steel||Good penetration||Cleans weld puddle||MIG takes cleaning|
|Titanium||Pulse current||DC TIG, cerium tungsten electrode||MIG only above 4mm thickness|
|Learning Curve||Easily learned||Very difficult||TIG takes both hands and a heat control, more settings|
|Welding Costs||Wire is relatively cheap||Machine and labor both cost more||TIG takes more time
MIG is faster, easier
Best Applications for MIG and TIG
When a job calls for welding thicker material or bigger pieces, the fast, productive MIG process will be a better choice. The continuous feed wire will be more productive compared to the TIG hand-fed rod at providing a large amount of filler material needed.
The accurate, precise nature of TIG welding makes it great for thin material that is susceptible to warping and burn-throughs.
Where there are numerous long runs, the MIG process can handle the situation with its continuously fed wire. Also, the TIG process requires many stops and starts to get new rods or adjust the rod in your hand. This increases the chance of creating a weld defect in a long bead.
TIG welding works best in short runs, such as pipe joints.
Since you only need one hand to run a MIG torch, you have a free hand to balance yourself or to hold pieces.
Bench or Shop Work
TIG will not work well when you are out of position. But for bench or shop work, you normally are not out of position. This makes this work a good candidate for TIG welding.
MIG simply can create more feet of bead in an hour than TIG and install more “pounds” of weld filler. When high productivity is needed, MIG welding is the go-to method.
Less Experienced Welders
MIG welders with lesser experience can lay good beads on a project with the easier-to-learn MIG process. But they may not be able to do so with a TIG welder.
More Experienced Welders
TIG welding is harder to learn, but if your or your employees have the experience, it gives you the option of using TIG welds when it is the better welding process.
MIG vs. TIG, which is best for beginners?
Are there different types of MIG welding?
What are the variations of TIG welding?
How do MIG and TIG compare to stick welding?
Are there any special safety concerns for MIG and TIG?
Each process shields the molten weld puddle from air and surface contaminants by flooding the arc region with inert gases, which don’t react to other chemicals. Finished welds are much stronger, more consistent and much cleaner without contacting the air while it reaches fusion.
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