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Flux-Core vs. MIG

From a performance standpoint, MIG welding offers a cleaner weld than flux-core, which means less grinding in the finishing stage and less chipping/brushing to remove flux before re-welding a joint.  But the added advantage of shielding gas comes with a cost both in terms of complexity and dollars.

The welders listed here come in three variants: flux-core only, MIG conversion capable, and MIG ready.  MIG-ready units come with the co-axial torch cable, regulator, and other materials necessary to hook up your gas bottle to the unit, while “conversion capable” units require an additionally-sold kit to convert to MIG use.

Most of the MIG units in our comparison are sold as “ready to weld” with flux-core wire.  To MIG weld, you’ll need to add solid-core wire (not a big deal as it’s even cheaper than flux-core) and a gas bottle (which is a big deal as it’ll likely cost $100-$200 to rent).  And while you might be able to get away by tying the bottle to the wall for a short time, eventually you’re going to want a cart to carry the welder and bottle to make things simple.  (Either way you’ll need to secure the bottle carefully, as the high pressure contained within — as much as 2000+ PSI — can turn that heavy bottle into a missle, as anyone who’s seen an episode of the A-Team can attest.)

An additional advantage to MIG welding is the ability to eventually swap in different wire and different gas combinations to allow you to weld materials other than mild steel, such as aluminum and stainless. 

Your choice here really comes down to how much you’d like to invest and what you intend to do with your welder.  If you’re going to be working with mild steel only and want to make the minimum possible investment, a flux-core unit will work fine for you.  They’re simpler to use, more compact, and some of the lowest-priced units.  If you think you might want to move on to MIG welding later, consider picking up a conversion-capable unit.  Or if you’re ready to jump in with both feet, go ahead and get a MIG-ready welder.

Key Manufacturer Specs

Welding Amperage/Duty Cycle 

SpecsThe most basic component of a welder is its power supply.  You’ll note that the welders listed above all put out far more amperage than the 20A that they draw from the wall.  To accomplish this, the welder stores up power internally and provides it to the gun when you pull the trigger, sort of like a water tower stores up water from a slow source (like a lake) and provides faster flow during peak need.  Obviously the welder can’t put out a greater amperage than it takes in forever; it must “take a break” every so often to recharge. 

Correction: As reader Cybergibbons commented below (and numerous others emailed to us), our analogy isn’t quite right here.  The welder doesn’t as much store energy to provide greater amperage as it does step down the line voltage.  Therefore, duty cycle (described in the next few paragraphs) is determined not by power storage capability, but rather by the thermal capabilities of the various power supply components.  Thanks for setting us straight!

Manufacturers provide two specifications to give you an idea of how capable the unit is at storing and delivering power: welding amperage and duty cycle. 

Duty cycle is a measurement of how many minutes out of ten you can weld with the unit before it must stop to recharge.  For example, if the unit could weld for two minutes out of every ten, it would be said to have a 20% duty cycle.  Clearly the duty cycle will change based on the amperage load, so any duty cycle measurement will be fixed at a particular amperage.  For example, you might see a duty cycle listed as 20% @ 90A.

Welding amperage indicates the range of amperage that the unit can provide under the most extreme conditions.  To put all this into perspective, consider a welder spec’d at 30-120A welding amperage with a 20% @ 90A duty cycle.  While you can weld at 120A (to handle thicker material), this particular welder will operate at a lower duty cycle than the listed 20% above 90A.  However, at 30A you’ll likely see a far greater usage percentage.

One way to tell a quality welder is by a longer duty cycle, but be sure to compare apples to apples.  A welder with a 20% @ 70A duty cycle doesn’t compare favorably to a welder with 20% @ 90A.  On some of the least expensive units you’ll often find duty cycle specificed at 60A or less, which isn’t enough to handle the thicknesses you’re most likely to see in basic steel fabrication.

Weld Thickness

Higher amperage allows you to place more heat into the metal, and therefore allows you to weld thicker material.  You’ll note in the comparison chart that weld thickness corresponds almost directly to amperage range, where units with the widest amp range can tackle the widest range of thicknesses. 

Watch out for spec sheets that show the ability to weld much thicker material than other welders with comparable amperage ranges; usually this means that they’ve included “multi-pass” welds in their spec.  (By making additional passes, it’s possible to weld material thicker than your welder can penetrate in a single pass.)  While this is useful information, you’ll want to make sure you’re comparing single-pass to single-pass or multi-pass to multi-pass.

Gun Length, Ground Length, and Power Cord Length

Cable lengthWhile not super critical, longer cables give you the ability to work farther away from the wall plug — a useful capability.  Many of the units listed here offer 8′ or 10′ gun cables, and you can easily find the length of the other cables in the product manuals.

Read the Product Manual 

An important note:  the product manual often provides much more information than you’ll find on the box or in an online product description.  When you’re shopping, the best way to get the real “scoop” is to download and read the product manual.  The manuals for virtually all the welders listed here are available from the manufacturers online and contain complete specs, parts lists, and lots of other details.

Read on for our recommendations.

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22 Responses to Getting Started Welding: A Comparison of 14 Flux-Core/MIG Welders

  1. Cybergibbons says:

    The water tower analogy with the duty cycle in this article isn’t correct – the welder doesn’t have any significant amount of energy storage inside it. The reason the current is higher is because the voltage has been stepped down. The duty cycle is because the wires and components aren’t rated at full current and would overheat if used all of the time.

  2. Eric says:

    You may want to dig a little deeper into the theory of operation for welder power supplies. Duty cycle is dependant on the ability of the welder to cool it self, not the amount of electricity it is “storing”. MIG welders work by taking wall voltage and stepping it down (usually with a transformer) to the voltage you are going to be welding at, then rectifying it to DC. Other than the energy stored in the magnetic field of the transformer and perhaps a few capacitors here and there, no energy is stored for later use.

  3. Colby says:

    The Hobart Handler 125 EZ can be had for $354.89 at Sears. Thanks for the article, I’ve been looking for some advise like this as I really want to buy a welder.

    Here’s the Sears link.

  4. Roy Ortiz says:

    You should do an additional story on welding aluminum with a MIG welder. Do the same chair but with aluminum.

  5. MARK SLONKA says:

    Excellent article !

    Now I don’t have to spend hours explaining welding to my brother !!!

  6. tim says:

    actually you are wrong in stating that a mig welder will weld thicker material than fluxcore. fluxcore will weld thicker metal better with better penetration than mig all other things being equal

  7. jake k says:

    Thanks, even with the small error’s re stored energy and flux vs mig for penatration and weld material thickness your explanation is very helpful. It should make a newbiees decision easier!!!

  8. Moo says:

    Great article – helped me a lot. Yeah, there’s a couple of factual errors that should be fixed… but they don’t affect the target audience (welding newbies) – so lighten up people. I get tired of the know-it-alls who just HAVE to make believe they’re smarter than they guy who did the research. Let’s see YOU crank out some articles that help others, instead of just blowing smoke up everyone’s arses. Bottom line, this was an informative, info-dense piece that is going to help a lot of people who want to get in to welding. Good job!

  9. Moo says:

    Oh…and PS…. let’s see you know-it-alls do all of the above for what Chuck got paid for this.. probably $0.

  10. Thank you for posting this entry level welder comparison article. After reading this article and the Lincoln electric manuals/literature I still cannot figure out the difference between the Lincoln 140C and 140T models. I understand that the C is for “continuous start” and the T is for “Tap start”. Please explain what this means and how it applies to welding.



    • Dugndeep says:

      C means continuous voltage selection as to where the voltage dial goes from 1-10 and anywhere in between and the T means tapped as to where the voltage dial goes 1-4 and no where in between so you just have 4 positions for voltage on the tapped machine and continuous voltage selection from 1-10 on the C machine.

  11. Charlie H. says:

    I’m coming in a bit down the road, here, but I’ve been researching for a bigger 110v welder. I just read (somehwere) the ‘C’ stands for rheostat. Brand wise I’m leaning toward a lincoln either the Weldpac 3200hd, Power mig 140, or Pro mig 140. Cept I can’t quite see the significance between these verses the money difference. If in doubt go for the middle one, I guess. Enjoyed the comment’s.

  12. Bob says:

    I have sure enjoyed the informative links on your website. Great information and will visit regularly.

  13. Alec says:

    Chuck thanks for an informative article, Though I’m a total newbie to welding, your article helped explain the differences between mig, flux and stick welding and how it would relate to my welding projects. In fact your article helped me with my decision to purchase the Lincoln Electric Weld Pak 125HD.


    San Diego, California

  14. Rachet says:

    I`m a newb to welding and i`m soon to get my hands on a Pro-Core 125Mig Flux-Core wire welder. At $419, it isnt the cheapest to buy but I figure the best bang for the best welder company out there buck. I`ve looked around at a few places and a few sites and found it to be the best. The reason i`m going for it is simple, most other models have no or very odd types of heat switchs or no good switchs at all, and this model has a plain easy to read heat dial. The arcticle is awesome and Hope to get some more tips and info for MIG welding! Keep it up guys!

  15. Rachet says:

    Oh and P.S. That Welder is a Lincoln.

  16. Crazy Horse says:

    Crazy Horse Custom Motorized bicycle builder just got new valentine’s day gift from the wife! She purchased the Chicago electric 90amp flex-wire 115v welder. It was on sale for $109 at Harbor Freight Tools and the helmet was half-price, too. This welder is to be used for welding custom-made motorized bicycles. Will consider later upgrading this entry-level welder to gas if the need arises. I appreciate this article and all the information contained therein. Thanks guys! Check out some of my custom-made bicycles at photobucket – search for Crazyhorse krzndn. I’ll keep you all posted on how the welder works out for me.
    Crazy Horse

  17. This is a superb product. Development is good and the product performs to 100% of my expectations. As an aside, this the third Palaris I have bought over the years.

  18. Owen says:

    Im new to welding so for my first welder i bought the Jobsmart 125 Mig/Fluxcore Welder from the Tractor Supply Company. I’m a former Commercial Electrician and I’m wondering what would happen if I beefed up the power cord and the grounding electrode do besides void the warranty?

  19. lee meadows says:

    can a mig welder weld aluminum?

  20. can a mig welder weld aluminum?

  21. Richard says:

    Are you saying that MIG Welders which cost less are not worth buying? What about the Ironton Reconditioned Flux Core 125 115V Flux Cored Welder for $99 or the Forney EZ Weld 299 for $149 ?
    I’ve never welded & don’t wish to spend close to $1000 to find out if I can use it.

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