What is a Multi-Process Welder, and When do You Use It?


what-is-a-multi-process-welder

What do cars, skyscrapers, and spacecraft have in common?  Without modern welding techniques, they would not be possible.  Amazingly powerful welding tools are becoming increasingly accessible as welding equipment continues to evolve with advancing technology.  Among the most functional of these tools are multi-process welders, which for many operators, are a real game-changer.

What is a multi-process welder, and when do you use it?  A multi-process welder is a welding machine that is capable of performing multiple types of welding processes. Multi-process welding machines thrive in scenarios where welding equipment must adapt to ever-changing job needs such as different base metals, varying workpiece thicknesses, and specialized welding joint types.  There are even specific multi-process welding machines that can function as plasma cutters.

The base analysis as to whether a welding machine suits your particular needs is essentially the same, whether it performs only one welding process or four processes.  The main question to ask is which welding processes you will need.  Read on to find out all you need to know about multi-process welding machines.

What is a Multi-Process Welding Machine?

Welding is a highly specialized process by which two pieces of metal are fused so that they essentially become one.  Through the welding process, the base metals are melted to a liquid state at the point where they meet (known as the joint).  As this molten pool cools and hardens, the newly formed weld takes on the same strength and anti-corrosive properties as the parent metals.  A welded joint is often more durable than the workpieces themselves.

Related reading: The 8 Strongest Types of Welds

A multi-process welding machine (also known as a combo welder or an MP welder) is a single piece of welding equipment that is capable of performing two or more welding processes.  By merely switching one type of welding apparatus (e.g., a TIG torch) for another (e.g., electrode holder) and making the appropriate connections, an operator can transition from one welding process to a completely different one in a matter of minutes.

What You Need to Know About Welding – A Rundown of the Four Primary Types

There are many types of welding processes, some that are adaptable to a broad range of applications and others that are highly specialized.  The two general categories of welding are arc welding and torch welding.  Where arc welding utilizes electricity to create a super-heated arc, torch welding (also known as gas welding and oxy-fuel welding) uses a gas mixture ignited through a torch to melt metal pieces.

Arc welding is far more common in today’s welding applications, and accordingly, the welding processes performed by multi-process welding machines all belong to the arc welding family.  When it comes to arc welding processes, there are only four that are significant: 

  • stick welding
  • flux-cored arc welding
  • MIG welding
  • TIG welding
Gas-Tungsten-Arc-Welding-GTAW
TIG Welding

A growing number of MP welders are capable of performing all four processes, but the majority of multi-process welding machines on the market today offer less, typically three processes.  The following are standard configurations of available arc welding processes on combo welders:

  • MIG + flux-cored + stick combination – MIG and flux-cored welding go hand in hand because they both utilize a consumable electrode wire that is fed through the welding gun from a spool.  As such, you will rarely see a MIG welder that is not capable of performing flux-cored welding and vice versa.  These two processes are often bundled together with stick welding in MP welders. (Stick welding is the most common and popular arc welding process.)
  • TIG + stick combination – Between these two processes, virtually every type of metal is covered, while encompassing a broad range of workpiece thicknesses.  This is a highly functional combination as you have the brute force and raw power of stick welding on the one hand, and the highly specialized, high-end welding capability of TIG on the other.
  • MIG + TIG + stick combination – This is essentially a four-in-one combination when you consider that the MIG gun can also perform flux-cored welding.  A growing number of reputable manufacturers are offering multi-process machines featuring this bundle of welding processes.
  • TIG + plasma cutting combination – As multi-process welders go, this is an uncommon combination for specialized applications.  What is does permit, however, are workpieces to be cut and immediately welded with no drop-off in the workflow (provided that the base metal is not cast iron).

To better appreciate and evaluate the overall value of multi-process welding machines, it is essential to understand the individual arc welding processes, including how they work and how they differ from each other.

Stick Welding

This is perhaps the most commonly used method of arc welding.  Stick welding is also referred to as shielded metal arc welding (SMAW) or manual metal arc welding (MMAW).  Stick welding utilizes a consumable electrode consisting of an inner wire and an outer flux.  The wire melts during welding and provides filler material, while the flux provides gas shielding to prevent oxidation.

It is perhaps the most versatile of the four primary arc welding methods and can handle welding jobs involving just about any type of metal.  Stick welding can even handle rusty or dirty metal surfaces and is particularly useful in welding thicker pieces of metal.  This method can be performed in windy conditions outdoors and can even be used underwater.

The limitations of stick welding are:

  • Should not be used on workpieces thinner than 1/16th of an inch
  • Electrodes are consumable and must be replaced frequently
  • This process can produce significant spatter
  • Slag is a by-product of this process and weld must be cleaned of slag before further treatment
  • Can be challenging to learn, particularly striking an arc and maintaining it

Flux Cored Arc Welding

Like stick welding, flux-cored arc welding (FCAW) relies on a consumable wire that creates and maintains the arc and also provides filler material for the weld pool. Also like stick welding, FCAW wire incorporates flux materials that provide the shielding gas needed to protect the weld from oxidation and other forms of contamination. 

Unlike stick welding, the electrode for the flux-cored arc welding method does not come in the form of a rod, but rather, a continuous wire that is fed at a constant speed from a spool.  FCAW is well suited for windy outdoor conditions, is adept at welding rusty workpieces, and can handle thick and thin metals, including steel and aluminum.  This is one of the faster welding methods and can be automated.

The limitations of flux cored arc welding are:

  • Electrode wire is more costly than stick welding or MIG wire
  • Initial equipment set up is more costly than other welding methods
  • Emits potentially dangerous fumes and therefore requires proper ventilation of work area
  • This welding process produces slag which must be removed from welds

MIG (Metal Inert Gas) Welding

Also known as gas metal arc welding (GMAW), MIG welding is similar to flux-cored arc welding in that it requires an electrode wire that is continuously fed from a spool as it is consumed during the welding process.  This method is widely considered the easiest welding technique to learn and master, mainly because the welding is trigger activated from the welding gun – pull the trigger to weld and release the trigger to stop (it has been likened to using a caulking gun by some).

Related reading: 9 Different Types of Welding Processes & Their Advantages

The gas shield needed to prevent contamination of the weld comes not from the electrode nor the wire but from an external gas tank that feeds gas into the MIG welding gun.  The shielding gas for GMAW welding is typically a mixture of argon gas and carbon dioxide. However, ultimately, the type of shielding gas used will depend on the particular metal being welded.

MIG welding is favored by many welders for its ease of operation and incredible versatility.  It can weld just about any type of metal or alloy, in virtually any welding position (e.g., horizontal, vertical, overhead).  This process does not produce any slag and is relatively spatter-free, so the final product is clean and does not require any additional finishing work.

The limitations of MIG welding are:

  • MIG welding requires that the workpieces be thoroughly cleaned before welding
  • MIG welding equipment is typically more costly than other welding methods
  • Although the welding itself is straightforward, the initial setup can be extensive and difficult
  • Because of the delicate nature of the shielding gas, MIG welding cannot be performed outdoors in drafty or windy conditions
  • MIG welding is not well suited for restricted or confined workspaces
  • Requires separate bottled gas for arc shielding

TIG (Tungsten Inert Gas) Welding

In the eyes of many welders, TIG welding is the highest tier of the welding craft, demanding the most skill to execute and deliver the highest quality welds accurately.  It is through this method that a welder’s talents can truly shine.  In the hands of a skilled and experienced welder, a TIG welding torch can produce highly intricate, complex welds that are aesthetically pleasing with unparalleled strength. 

Also known as gas tungsten arc welding (GTAW), this method can weld virtually any type of metal or alloy.  Unlike the other arc welding techniques we have examined, TIG welding does not involve a consumable electrode.  Instead, the arc is created and manipulated with a tungsten electrode that is mounted at the tip of the TIG torch.

Shielding gas is fed through the torch and usually consists of argon, helium, or a mixture of both.  Applications involving thin or lightweight workpieces do not typically require filler material, but most TIG jobs do require some type of filler metal.  A TIG welder must utilize both hands, one to hold the TIG torch and the other to apply the filler material to the weld pool.  This can be a laborious and time-consuming process, but the weld quality is simply unmatched.

The limitations of TIG welding are:

  • Because it is more labor-intensive than other welding techniques, it is more costly and time-consuming
  • TIG welding equipment is typically more costly than other methods
  • TIG welding requires a higher degree of skill on the part of the operator
  • TIG welding cannot be automated, thus limiting its applicability in industry
  • TIG welding is a slow and deliberate process
  • Because of the delicate nature of the shielding gas, TIG welding cannot be performed outdoors in drafty or windy conditions
  • Requires separate bottled gas for arc shielding

Related reading: How to Use a MIG Welder Without Gas | Is Gasless MIG Welding any Good?

When Do You Use a Multi-Process Welding Machine?

As we have seen, certain welding processes are better suited for working with particular metal types than others.  Additionally, the different welding processes have varying capabilities for workpiece thicknesses.  Thus, with their ability to perform multiple welding processes from the same piece of equipment, multi-process welding machines are best suited for applications that routinely require working on:

  • Multiple base metal types
  • Various workpiece thicknesses
  • Different types of welding joints
  • Out of position welding
  • Indoor and outdoor applications

The value of combo welders lies in the convenience and efficiency of seamlessly transitioning from one welding process to a different welding process with minimal effort.  Whether the welding work is being performed in a workshop or on the go, the benefits associated with uninterrupted workflow and optimized productivity cannot be overstated.

Following are a few examples of industries and businesses that benefit significantly from the use of a combo welder:

  • Automotive fabrication and repair – With so many parts and assemblies, the automobile fabrication and repair industries are perfect fits for the capabilities of a combo welder.  From welding larger, thicker workpieces that require brute welding power to smaller components with thinner material requiring more finesse, an MP welder is in its best element in these types of environments.
  • Aerospace industries – More so than perhaps any other industry, aerospace fabrication places a premium on welds of unmatched strength and integrity, often on base metals, one typically does not see.  TIG welding figures prominently in this arena for its intricacy and the incredible range of workable metals, while MIG is also widely used because it is adaptable to automation.
  • Construction – The ability to weld outdoors using either a stick or flux-cored process, and within a matter of minutes transition to intricate TIG welds on thinner, more delicate workpieces is a powerful capability.  With a multi-process welding machine, this is routine, which is why this type of equipment is essential throughout the construction industry.
  • Independent welding shops – Small, independent fabrication shops typically have limited resources compared to larger businesses.  A quality multi-process welding machine enables the independent welder to perform just about any welding job, reducing equipment costs and even conserving valuable workshop space.
  • Facility managers and engineers – Heads of facilities and engineering departments understand the wide-ranging, and often unpredictable, needs of a massive, institutional operation.  From factories to hospitals to corporate campuses, a multi-purpose welding machine is an absolute must-have for performing on-the-spot repairs and major renovations.
  • Artists and hobbyists – An artist will go wherever their inspiration takes them. In the case of artists whose medium is metalworking, the flexibility to work with any type of metal, of virtually any thickness, is paramount to each finished piece reflecting the artist’s vision.  The same can be said for hobbyists, whose welding needs may very well be more demanding than professional welders as far as breadth of workpiece materials. 

Related reading: Advantages of Being a Welder >>Salary, Working Hours | Worklife Balance

Are Combo Welders Good?

When multi-process welding machines were first introduced, the initial knock on them was that while they were capable of performing multiple welding processes, they did not execute any of them very well, save perhaps one function.  That criticism has mostly subsided, and a growing number of seasoned welders have come to embrace the incredible functionality of combo welders.

A multi-process welding machine truly proves its worth when transitioning from one welding method to another (e.g., from TIG welding to stick welding) within a few minutes and with minimal hassle.  The alternative of setting up an entirely separate machine to perform a different welding method seems inconvenient and inefficient by comparison.

What is the Measure of a Good Multi-Process Welding Machine?

Ultimately, an assessment as to whether a multi-process welding machine is worth its purchase price requires an evaluation of the welding processes it claims to perform, both individually and collectively, as well as any additional features that enhance its overall value. 

As experienced welders can attest, certain criteria must be met for a particular welding process to be performed safely and adequately. An excellent place to start is by reviewing the different arc welding processes and highlighting the types of metals they are capable of welding.

  • Stick welding – steel, stainless steel, and cast iron
  • MIG and flux-cored welding – steel, stainless steel, and aluminum alloys
  • TIG welding – steel, stainless steel, aluminum alloys, chromoly, copper, brass, magnesium, titanium, and other exotic metals
Metal TypeMIG WeldingStick WeldingTIG Welding
SteelXXX
Stainless SteelXXX
Aluminum AlloysXX
Cast IronX
CopperX
BrassX
Exotic MetalsX

Another important metric is the variance in workpiece thickness for each of the different welding processes that a multi-process welding machine can weld.  As a general rule of thumb, a welding machine needs to deliver one amp of output for every .001 inch (one one-thousandths of an inch). 

Related reading: How Many Amps Do I Really Need for a MIG Welder?

The table below summarizes standard metal thickness to the required amperage requirements:

Metal Thickness (Fraction of an Inch)Corresponding Gauge NumberApproximate Amp Output Needed
3/64” (.047)1847 amps
1/16” (.062)1662 amps
5/64” (.078)1478 amps
1/10” (.100)12100 amps
1/8” (.125)10125 amps
5/32” (.156)8156 amps
3/16” (.187)6187 amps

It should be noted that these amperage and metal thickness figures are approximations; actual performance will vary from machine to machine, but at least now amperage numbers mean something and can point you in the right direction.  As a general rule, the higher the amperage output, the better, and you need not bother considering any combo welder with less than 50 amp maximum output.

With amperage output serving as a good indicator of a multi-process welding machine’s welding capacity, it is worth noting that a great many multi-process machines on the market possess the desired amperage range, with popular brands offering tiered MP machine models with amp output ranging from 140 for entry-level machines up to 400 amps for semi-industrial machines.

Drawbacks of Multi-Process Welding Machines

Combo welders are not perfect, and they are certainly not the right answer for the needs of all welders, which is why it is vital to make an informed decision before purchasing one, weighing the benefits versus the disadvantages, while also considering things like cost, warranty, and other essential factors. 

Here are the main drawbacks of owning a multi-process welding machine:

  • Breakdowns can be very costly – While having multiple welding processes available at your fingertips has significant benefits, the obvious Achilles heel of having so much capability in a single machine is that if that one machine were to become inoperable, all of your welding operations would come to a screeching halt.
  • Machine price – As with so many other types of equipment, the convenience and efficiency of having multiple welding capabilities from one machine is the cost.  While a multi-process machine capable of performing four types of arc welding would undoubtedly cost less than four separate machines for each welding method, the price range for a medium-duty combo welder from a reputable manufacturer will range from $400 to over $1,000.
  • Included accessories – Multi-process machine manufacturers typically include an extensive assortment of welding accessories so that these welders are ready to tackle a wide variety of welding tasks straight out of the box. However, it should come as no surprise that many of the individual components that are included with the combo welder are adequate to get you started, but are by no means top of the line accessories.  This is particularly true of the TIG torches, MIG/flux-cored guns, and stick/electrode holders.
  • Limited portability – Having up to four arc welding process capabilities out of a single machine comes at another cost, that being one of portability.  The very nature of what an arc welding machine does requires that even the most basic of models weigh in at about 20 pounds.  For a high-end multi-process welding machine with semi-industrial capabilities, you can expect that weight to balloon to well over 70 pounds (and that excludes the accessories you will also need to weld).

Relate reading: Portable Welding Machine Buyer’s Guide: 5 Things to Look For

Since making an informed decision means knowing the good together with the bad, it is crucial to be aware of potential drawbacks ahead of time.  In the case of multi-process welding machines, for the right application, this balancing act weighs in favor of purchasing one.

6 Best Multi-Process Welder to Fit Your Budget    

Knowing what to look for in a multi-process welding machine is challenging enough, but finding one with the performance capabilities you seek while fitting within your budget can be a daunting task.  In this section, we examine the best MP welder options at various price points, starting with machines for less than $300 and working our way up to multi-process machines that cost over $2,000. 

NumberBest Multi Proces Welder at various price pointsPrice
1Weldpro 155 Amp Inverter MIG/Stick Arc WelderUnder $300
2Easy Weld 140 MP Multi-Process Welder$300-$500
3Everlast Power ITIG 201$500-$700
4AHP AlphaTIG 200X$750-$1000
5Everlast Power MTS 211siover $1,000
6Miller 951674 Multimatic 215 Multi-process Welder with TIG Kitover $2,000

Less Than $300 – Weldpro 155 Amp Inverter MIG/Stick Arc Welder

Weighing in a mere 20 pounds, the dual-voltage Weldpro 155 multi-process welding machine offers MIG, flux-cored, and stick welding capabilities at both 110 and 220 volts.  Despite its compact size and sub-$300 price-point, this combo welder has a 155-amp output, which translates to the capability of welding 1/4 inch thick mild steel in any of its three welding modes.

$300 to $500 Range – Easy Weld 140 MP Multi-Process Welder

With its distinctive green shell, the Easy Weld 140 MP combo welder is a 4-in-1 machine with MIG, flux-cored, TIG, and stick capabilities.  With its rugged construction and weighing just a touch over 20 pounds, this multi-process welding machine is well suited for any environment.  Its maximum output of 20 amps puts 1/4 inch workpieces well within its welding capabilities.  Best of all, this is a 120-volt machine, meaning you can take it anywhere.

$500 to $750 Range – Everlast Power ITIG 201

Another dual-voltage multi-process machine, the Everlast Power ITIG 201 checks in at beefy yet very portable 40 pounds, and offers TIG and stick welding capabilities.  Packing 200 amps of maximum output, this Everlast machine can weld steel up to 5/16” in a single pass at 240 volts and steel up to 1/2” in multiple passes at 240 volts.  For added flexibility, it can also weld off standard 120 volts.

$750 to $1,000 Range – AHP AlphaTIG 200X

With an impressive 200 amp output and dual-voltage capability, the AHP AlphaTIG 200X is capable of TIG welding intricate and lasting joints and stick welding 1/4” aluminum and 3/8” mild steel.  At just a hair under 70 pounds, this multi-process welding machine can weld on the go when needed, but its actual value lies in the pulse and power modulation technology that makes this welder easy to operate.

Over $1,000 – Everlast Power MTS 211si

Although it is a relative newcomer to the welding machine arena, Everlast has already made itself known in welding circles, and its Power MTS 211si demonstrates that it is already a force to be reckoned with in the highly competitive multi-process machine market.  TIG, MIG and stick welding capabilities are powered by 200 amps of output making metal thicknesses ranging from 1/4″ to 5/8” routine affairs.

Over $2,000 – Miller 951674 Multimatic 215 Multi-process Welder with TIG Kit

From one of the most prominent brands in welding equipment comes the Multimatic 215 multi-process welder featuring TIG, MIG, and stick welding functions.  Although welding power and capacity are hallmarks of Miller welding equipment, the finer details like the LCD, the intuitive operator controls, and the built-in smart technology that automatically detects connected accessories are what make this combo welder one of the best in its class.

Conclusion

The multi-process welder is the machine equivalent of a multi-tasker.  But rather than performing tasks simultaneously, the combo welder seamlessly transitions from one to another, saving the operator valuable production time and maintaining optimal workflow.  When factoring in the cost savings of not having to purchase separate machines for each welding process, the decision to purchase a multi-process welding machine seems like a very wise one.

Are Multiprocess Welders Prone to Failure? >> Check out the video below

David Harper

David is the Co-Founder and Senior Editor at weldingtroop.com. David's an experienced fitter and tuner/welder who's passionate about helping others develop in life through new skills and opportunities.

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