MIG Welding vs TIG Welding
There is always the debate about mig welding vs tig welding particularly about which is better, more versatile, can be relied more and cheaper to use. However, MIG and TIG welding are both essential welding applications that without one, our metal construction and fabrication work would never be the same. MIG (Metal Inert Gas) is known to be the most user-friendly among all welding applications with regards to arc welding. As they say, it is just a matter of “point and shoot” with MIG welding.
On the other hand, TIG (Tungsten Inert Gas) welding is popular among hobbyists and DIY guys who commonly use thinner metals and mostly non-ferrous metals in their work. And people think this is the weakness of MIG welding because of the high-density heat it gives out. Yet, MIG welding can also deal with these metals if only welders learn how to adjust their parameters and use the right combination of gases.
So if we talk about Mig Welding vs Tig Welding there is so much we need to know. Not only about how we do their welding process but also how they work, what consumables they need, what metals they are good for and what kinds of gases they need to utilize their full potentials. But how do these two useful welding applications start?
History of MIG and TIG Welding
Both mig and tig welding have interesting histories. MIG principles were pursued during the 1800s with the discovery of electric arc and so carbon electrodes were used. However, its method did not go well. In the 1800s the metal electrodes were discovered but it was only in the 1920s that GMAW (Gas Metal Arc Welding) was invented by General Electric’s P.O. Nobel. Yet, this method has not been of practical use because there’s no use of shielding gas while Direct Current is used.
In 1948, a few years after World War II, GMAW became fully functional. The wire electrode has become smaller, the voltage power source became constant and the use of argon gas as shielding gas has been discovered. Argon gas is best used in fusing aluminum but unfortunately, argon gas was expensive and so GMAW remained unpopular. In 1953, carbon dioxide (CO2) was introduced and this is the beginning of MAG (Metal Active Gas) welding. CO2 is cheaper. However, using it in pure form can cause bad effects on non-ferrous and thinner metals so inert gases are needed. This is now what we call the MIG (Metal Inert Gas) welding.
TIG welding was invented by Russel Meredith in the 1940s. He was successful in creating this technique using argon (AR) as the shielding gas because of the necessity to use a welding application that could deal with aluminum and magnesium alloys. These metals are both essential in building ships, airplanes and other significant machines needed to boost up the trade industry. In the 1970s, Miller Corporation created the square wave feature as the TIG’s amperage control feature. This is the predecessor of the pedal-type amperage control that only the TIG welding possesses among all welding applications.
Difference Between TIG and MIG welding
So what is the main difference between tig and mig welding? First, we have to know that MIG and TIG welding both use electrical arcs in producing heat to join metallic objects. They also both need gases for shielding and require electricity to ground up the torch so that when the electrode touches the metal, it creates an arc. In MIG welding, the electrode comes out of the torch which melts into a weld pool. In TIG welding, which is also called Gas Tungsten Arc Welding (GTAW), the electrode is a non-consumable tungsten rod that creates the arc and the filler is a separate metal stick that is melted by the arc produced by the tungsten.
MIG welding needs a spool of wire electrode that should be installed in its mechanism to feed to the torch. This consumable wire serves as the filler that melts and joins metals together. To shield the weld pool during welding, a shielding gas is needed and this is where CO2 is very much needed. Acting as a shield, it can also intensify the heat inside the welding pool making the molten electrode more penetrable.
When it comes to mig welding vs tig welding current requirements, most MIG welders require DC (direct current) because it needs constant polarity for a smoother welding output. And because CO2 is already a hot gas, the current the MIG machines need is in DC for a faster deposition rate. However, spatter could be a problem that’s why the mixture of argon could be useful. In case MIG welding should be used on stainless steel which contains chromium which is an alloy, the current should be changed to AC and CO2 should be mixed with argon preferably in the ratio of 75% argon and 25% CO2. This combination is what we call C25 and using this can lessen the production of weld spatter while the melted filler can become more penetrable.
TIG welding also needs gas for shielding but its common shielding gas is argon. Argon is preferred to protect the molten electrode from oxidizing and nitrogen absorption that can be caused by the surrounding atmosphere. In TIG welding, it doesn’t differentiate the metal you need to weld whether it is stainless steel, mild steel, copper, or aluminum and you only need argon to weld to these metals.
Helium can also be used in TIG welding and can provide deeper penetration because it can produce a hotter arc. However, helium is an expensive gas and its arc can be easily contaminated. TIG welding also requires AC when welding soft metals. But when you have to deal with hard metals like stainless steel and mild steel, you should switch to DC. In this case, the tungsten electrode becomes the negative pole so you should also switch your machine’s polarity into DCEN (Direct Current Electrode Negative)
Another obvious difference between tig and mig welding is the use of their consumables. Consumables are usually found on the torch and they are called consumables because they can get consumed like the wire electrode or need to be replaced due to overuse, degradation, damages, erosion, or warping. In MIG torch, the consumables can include the electrode wire, mig liner, and small parts of the mig gun like the nozzle, retaining head, and contact tip. TIG consumables are usually found on the torch that includes collets, collet bodies, gas lenses, and nozzles. The filler electrodes are also TIG consumable but separate items from the torch. The tungsten electrode used on the TIG torch may erode in the long run but it is still not considered a consumable.
MIG Welding Advantages:
Learning MIG welding is easier from setting up the spool wire to understanding the troubleshooting procedures.
Experienced welders can do quick control of the parameters in MIG welding like the amperage and voltage setting, wire speed and gas flow.
It allows you to choose the wire electrode that can match your base material easily while there is a wide availability of wires in the market.
It can work with various metal materials of different thicknesses.
It can provide a low-cost but high productivity process which can lead to more productive outcomes.
With just a few adjustments on current settings and choosing the right electrode and gas mixture, it can be used for welding aluminum and other non-ferrous metals.
It is most preferred by welders when it comes to welding positioning. However, because the welding pool on MIG welding tends to become larger and more fluid, vertical and overhead welding can be a difficult process.
It can offer a deeper weld penetration with the right combination of gas and amperage settings.
Mig and tig welding can produce fumes but there are lesser fumes with mig welding.
It allows you for a deeper weld penetration especially if the C25 gas mixture is used.
Used in the industry for mechanized welding, it does not produce slags or spatters.
It allows you to shift to flux-cored arc welding which also allows you to weld even on a drafty environment.
If you need a complex mix welder like a 3-in-1 (MIG, TIG, Stick), this is more expensive than other multiprocess arc welders. It also becomes less portable and the parameters can be difficult to set up. So these types of machines can take longer for beginners to learn.
Because you will be using a MIG gun for welding, it would be difficult to move around your metal project if you are working in a constricted area.
Drafts or breeze can contaminate the weld pool by blowing out the arc shield which can cause oxidation. So MIG welding should not be applied in an outdoor environment unless when shifting to flux-cored welding or using a welding tent.
MIG welding is not advisable for overhead and vertical welding positions because these can result in lesser deposition rates.
Normally produce spatters and splatters.
TIG Welding Advantages:
It produces a more appealing weld and the best welding application when detailed welding precision is required.
The temperature coming from the current can be controlled manually or through pedal amperage control to ensure less spattering and better weld pool penetration.
You can see through the arc because argon produces a clear arc that enables the welder to observe his work and know what is happening with the electrode and the weld puddle. This is one obvious difference between tig and mig welding.
TIG welding can be used on a wider range of materials in creating new metallic forms like in fabricating equipment, vehicles, furnishings, utensils, and many other things that require refined welding finishing.
It can be the better choice when it comes to fixing projects that require varied welding positions including horizontal and vertical position and in fusing different metals of varied thickness.
Most preferred for joint welding, it will not restrict your movements even on narrow spaces because of the slow hand movements required.
Best method in welding rare earth metals like niobium, titanium, molybdenum and tungsten.
For welding thin and soft metals, TIG welding is the best and only requires AC either in 110V or 220V which are the common voltages we have in our homes and work sites.
You do not have to replace wires unlike with the MIG welding.
When it comes to mig welding vs tig welding, tig welding is more of a slow process and therefore it could take time to finish a large project. So time and speed are what make TIG welding its weak points. As such, the filler deposition rate is also much lower although the weld penetration is much deeper.
It is much harder to learn than MIG welding because TIG welding is specially designed to deal with thinner and softer metals and therefore the machines itself require experienced welders to set its parameters properly.
Argon and helium which are both inert gases are both expensive gases so these add up to the initial cost required for TIG welding.
If MIG welding is hotter than TIG welding, TIG welding is brighter which can expose your eyes to high-intensity light without the necessary precautions.
So these are what you can get from mig and tig welding so it’s up to you which could fit your kind of work and what your work or hobby requires.
Troubleshooting MIG and TIG Welding
TIG and MIG welders, because both use current to produce arc to heat elements are also prone to failures, problems and damages. But in every problem, obviously, there is a cause and here we will discuss the common problems that mig and tig welding usually experience. We will also discuss some of the best solutions to give you a head start whenever you encounter these issues.
Three Common MIG Welding Problems, Causes and Solutions
These are small gas pockets that got trapped in the weld metal and they could be on the surface or inside the weld. The problem with porosity is that these are signs of a weak weld which also means the weld is not purely solid and prone to breakage. The following are the causes of porosity as well as the solutions.
Dirty metal surface. If the surface has some rusts, oil, dirt, or grime, this can prevent the penetration of weld and the dirt underneath will act as cover preventing the filler to penetrate or stick to the metal.
Solution: You need to clean up the metal before you weld either by using a steel brush, chemical solvents, or a grinder if you will deal with paint.
Properties of the Base Metal. If the metal contains chemicals like phosphorus, this could also cause a porous weld.
Solution: Avoid using such metals as your base metals. Its elements can reject filler metals.
Lack of Gas Coverage. Using not enough gas due to improper gas flow setting or mig welding on outdoors with lots of drafts can also lead to porous weld.
Solution: Make sure you check the gas flow before welding. If welding outdoors, consider using a welding screen or settle for flux-cored welding.
MIG Wire Issues
Such issues can cause erratic feeding of wire and this can be caused by improper wire feeding. Here are the reasons.
Worn out drive roll. A drive roll is a ring-like metal with grooves which role is to guide the wire electrode smoothly into the liner of the mig gun.
Solution: Check the grooves of the roll. For any sign of wearing, replace it with a new roll.
Birdnesting. The wire got tangled inside the mig liner which halts its release from the MIG gun.
Solution: Release the wire from the tensioner and pull it out. Cut the wire from where it got pinned by the tensioner and reinsert the wire back into the liner. Make sure the wire is not too loose. If possible, use a larger wire.
Burnback. Slow wire feed or the nozzle of the gun gets too close to the base metal which melts the wire and fuses into the contact tip of the gun.
Solution: Replace the contact tip and increase the speed of wire. Keep a good distance between the nozzle of the mig gun and the base metal.
This could be caused by many factors but the most common reasons are high wire speed with low amperage or high voltage. It could also be the lack of shielding gas or dirty metal welding surface.
Solution: Increase the amperage or decrease the voltage while decreasing the wire speed. You can try and test with these three things until you get the right parameters and always check the gas flow.
Common TIG Welding Problems, Causes and Solutions
Rough, contaminated bead on aluminum weld where the filler metal mixed with the melted oxide. This can be caused by welding aluminum using DC or with the wrong polarity.
Solution: Even if you use argon, always set the polarity to AC to allow the electrode positive of the current cycle to blow away the aluminum oxide.
Weld contamination. The shielding gas could be too much or too little or the gas is not even turned on. In rare cases, there could be moisture in the tank.
Solution: Use only 100% argon or mixed with helium for aluminum. Check the gas flow rate including the hose and fittings. The ideal is 15 to 20 cfh (cubic feet/hr). Too much gas creates swirling turbulence and pulls in airborne contaminants. Too low gas provides poor coverage on the weld pool. Try using a gas lens instead of the standard collet.
Graininess on the weld. It can be the result of too hot welding which also causes based metal dilution.
Solution: Try to change filler metal from 5356 to 4043 but clean up the metal surface before welding also.
Incomplete fusion. This usually happens on fillet or T-joint. You could be holding the torch farther away from the spot which restricts the filler rod to feed the joint.
Solution: Reduce your arc length so you can have the proper directional control and to increase weld penetration. Also, do not rush in filling the joint.
Occurrence of craters and show signs of cracking. Can be caused by dropping the amperage too quickly or quickly removing the filler rod.
Solution: Slowly reduce the current when you observe craters are showing up and do not pull the filler electrode away too quickly.
Now that you know more about the difference between tig and mig welding, you might be able to distinguish now the problems and what you can do to troubleshoot and fix their issues. So when it comes to mig welding vs tig welding, you must be observant and do not be afraid to experiment or adjust what you think needs to be adjusted.
There could be a bit of differences between these two welding processes so it is important to know how these could provide you the advantages you need either in your work, hobby, or in fixing things at home.
If you are interested to know mig welder vs arc welding, we also have some discussions for you about this and you will also learn much about their differences and their advantages.