#1 Mistake Made When Flux Core Welding (one simple Trick)

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Is your flux core welder laying down some horrible welds? Before you give up on it check this trick out first! So many people including pro welders make the mistake of running the wrong polarity when using a gas-less flux core wire. For most general welding when using Stick (SMAW) and MIG processes you would use reverse polarity which mean (+) lead and (-) ground. This is also referred to electrode hot. The two processes that require straight polarity meaning electrode (-) and ground (+) are TIG and flux core (FCAW). Since MIG and Flux core are very similar it is very common that they are mistaken to both use the same polarity. So go out there and make sure you have your flux core machine set up properly before bashing it!

[@saaaaauce]

Noob here, and this might be the most useful video on welding I've run into. Thanks!

[@JTwelder.]

Thanks man!

[@Kurnacopia]

Outstanding video.....my whole time i've been welding i've had spatter everywhere....I was about to give up till I saw this. Thank you!

[@JTwelder.]

No problem glad I could help!

[@lestergillis8171]

​@@JTwelder.FYI:The splatter you are referring to are called-"BOOGERS"!

[@lestergillis8171]

​@@JTwelder."If you use slag, then DRAG".

[@poncethegayboi]

Dual shield

[@andrewallason4530]

Great video. Simple, easy to follow advice. I bought a MIG unit from a local, supposedly reputable specialist welding supplier about 10 years ago. It was a ‘special deal’, allegedly for our state agricultural show. Turned out, they were dumping the units as they were having major issues getting all the products from the manufacturer to operate correctly. After a few months of horrible welding, blaming myself, a mate (much more experienced than me) tried to use it, and had the same issues ( dirty, splattery, horrible weld lines, that took ages to grind, and major pitting necessitating rewelding / over-welding (?), incomplete or weak welds, machine would run for about 10 minutes then need 1/2 hour to cool down etc). I took the unit back for a ‘service’, and they sent it back with the wrong setting on the ‘drive-wheel’ for the wire that was on it. Eventually, I disassembled the machine. I found the cooling fan (generic ‘computer’ type) was rubbing on another component, so i rescrewed it onto the steel case. I then reset the incorrect settings that they had done. It now works flawlessly, and will easily weld for longer than I can. Took it back to the company, showed them what I did, and made the professionals a bit embarrassed. They gave me a bunch of new swag, including fancy switching- magnetic clamps. Sometimes it takes a new ‘inexperienced’ eye on a problem to pick out the issues.

[@bjaminf113]

Agreed!!

[@lancerobbinssr4546]

Got myself a Flux core welder trying to teach myself how to weld. And I thought I was a idiot who could never learn how. All disgusted Until I saw your video. Thank you for raising my WELDING I.Q. WITH KNOWLEDGE WORTH KNOWING. I HAVE A BIG SMILE ON MY FACE BECAUSE IM MOT A IDIOT WHEN IT COMES TO WELDING. IM STILL A IDIOT BUT I CAN NOW WELD! THANK YOU SO MUCH FOR YOUR KNOWLEDGE.

[@soulsharts]

I just started college this last week for a welding certificate knowing basically nothing about welding, but when you talked about straight and reverse polarity, I knew exactly what you were talking about because we're currently learning the basics. Straight polarity= Direct Current Electrode negative (current flows from electrode to work, transferring 70% of the heat on the work), Reverse polarity= Direct Current Electrode Positive (current flows from grounded work to electrode, transferring 70% of the heat produced to the electrode) and Alternating Current spreads the heat 50/50 towards electrode and work.

[@0727076740]

Great job now I knw

[@user-xc7mt8iq7d]

bougt just mma cried nicely.

[@lakerdigital]

I have to write this down.

[@FeatherHorseforge]

Learnt more in the last 12 minutes than I’ve ever been taught about welding🙂 thanks cobba

[@fredfrontino3706]

I've been welding off and on over 40 years. I never knew about this. I normally run gas, but I do have a couple of rolls of Flux core if I have to welding outside and there is too much wind. Now I'll know to make that change, and my welds will actually look good. Thanks for this very useful tip.

[@JTwelder.]

Glad I could help!

[@PhotoBobBarker]

This is one of the things that really impressed me with the HF Vulkin Omnipro220. The manual is VERY in-depth and actually covers this and WHY it is.

[@victoroneill7924]

This makes sense since DC current always flows from negative to positive. The instructions for my welder tells you to reverse the cables when welding with flux core wire.

[@zapa1pnt]

Jake, thank you. This is the best demonstration I have seen, of the difference made by changing polarity. I have been viewing (for the past year) many videos, on modding a flux core machine to DC.This shows the potential, of staying AC. 😁🖖✌

[@leebdj1949]

This is probably one of the best videos for anyone to watch that buys a box store welder to use around their garage. Without this simple tip, at the beginning of learning, it saves an immense amount of frustration, and disappointment. So glad I found this video. We have the exact welder at work for doing minor repairs etc, and it acts that way. Have to put feed higher, and keep turning the welder down to not burn the wire to the tip, and jumps back and forth, hard to keep straight. Sounds like it’s the exact problem. Awesome man!

[@Myrrapen]

Great info! Thank you for wearing correct PPE and demonstrating proper set up!

[@user-rs7xn8wt4r]

Now I know why the Small Lincoln single-phase 110 volt welders we had at our old shop were horrible to work with. Thanks brother! Appreciate your video! Great information! I mig weld now with a Snap-On mig with gas and non flux wire. Wow! What a difference! 👍

[@kenday7942]

OMG!! I have been running flux core on my Lincoln with wrong polarity all this time. No wonder I have been getting the results I get! (It ain’t pretty!!). Thanks SO much. I can’t wait to try out proper polarity. Thank you!!!

[@skitzdaniel3314]

Thank you for a great example of setting up and explaining setup for flux core. I am fairly new to welding and I heard about + ground for flux core, but hard to find a good explanation of it as you have given. I do make good welds with flux core. I like flux core over gas, over the cost of gas. Have no problem brushing the flux off the weld. I just upgraded to a Vevor 250 mig which allows easy switch to (+) ground.

[@lunarrn]

Thanks for the tip. I’ve been running Blue Demon flux core wire positive ground with great results.

[@kevingrant5910]

I was just having this exact problem so I went straight to KZbin. You saved the day Sir 💪

[@scottcampbell9078]

Thanks for doing this video. I bought a used Lincoln mig a couple years ago. I recently ran out of gas and installed flux core. I switched the polarity, but got the crap welds you showed. I just went & checked, and the polarity was wrong. Guess I've been running mig wrong, too.

[@Christopherbever]

That was one of the best explanations of polarity iv come across. Thank you

[@paulmanhart4481]

Thanks. I’ll give this a try. I’ve had a hell of a time with my Eastwood MIG welder using flux core. Paul

[@gusalmighty5098]

I have an older version of the same Lincoln you are using. I can smear some wire on two pieces of metal and make them stick together but I would never call myself a "welder". A lot of our stick welders where I work have a polarity switch right on the front so I knew that there was a purpose for reversing polarity but never new why. The funny thing is.....I have asked about it and none of the career "welders" at work could tell me why you would ever use it 😂 This will go a long way toward improving my results. Thank you!

[@duanefarland9988]

Great video, I’m a complete novice at this stuff and your explanation makes perfect sense. Thanks

[@therealsparkman]

I consider myself a weekend warrior and a self taught welder. I purchased a Lincoln 140C welder similar to yours, but instead of my amp settings being fixed to only five or six settings, I can actually fine tune the amperage with the dial. Picked it up in an estate sale for $350 and never used. A smoking deal considering the cost of this model new. At any rate, I, like everyone else made the assumption that the units were sent from the factory for the proper setting for flux core. And now you are proving that wrong. Good on you for bringing this to our attention. I thought that my welds weren't getting any better as shown in your example. I will reverse my leads the next time I have a small job and see if my work is any better. Great video! Cheers from Ontario.

[@wigidy12]

Cant wait to try this on my chicago electric cheapo. Been welding with stick for many years, but couldn't get a decent looking weld for nothing. Thanks!

[@allthecodys501]

We're cooking with flux now! Thank you, I was getting depressed. Im a novice but I knew I wasnt that bad

[@Billy-gl7im]

DUDE, for the last few months i was learning to weld and bro my welds were good but there was so much spatter and super inconsistent. Nlt kidding after one hour of swapping pos and neg i got some pro welds and im finally ready to weld my whole flatbed and not be ashamed of my welds! 🙏🙏🔥🔥🔥🔥🔥

[@steveo1006]

Stumbled on this video and was excited. Not a “welder” but did a year, at night, at local tech school and have TIG, stick and gas MIG in my shop. Needed remote operation at my farm and bought a HF 110v flux core machine. It was ugly but it worked. Recently helping weld on a bush hog and using the 120 machine and yea…messy. Saw this video and at 1115pm went out to my shop to see. HF 100v flux core welder is not switchable. It is all hard wired in and I’m not a sparky. Damn! Still great video and I plan to share this with my buddy who was my welding instructor.

[@tomfaltash9634]

A few years ago I purchased a Lincoln welder 240 . In the instructions it said “ if using flux core, reverse the polarity for optimal performance “. I just did and my welder has always worked amazing. Thought you still do get a bit of spatter , however common with flux core.

[@tomfaltash9634]

Don’t ever buy Chinese wire or rod to weld

[@ThisIsToolman]

Excellent demo.

[@jamesprice1549]

Most important welding video I have ever watched. Home Hobbyist and with a 12 year old Mig that has caused me nothing but heartache.

[@MrStaybrown]

Thanks. My mig was set up wrong on my 1st exhaust job. It was splattered and ugly. Flipped polarity and my 2nd exhaust job is nice.

[@wallacefrey6247]

This tip was a BIG help, thanks.

[@etarepsedllits48]

I bought the cheap Lidle "Parkside" welder, and I thought it welded really well, with little splatter. i've just checked it, and it was +;ve earth out of the box! Happy days!

[@CortinasAndClassics]

Bloomin brilliant. I will be swapping my polarity n my flux core 👍🏻

[@CT9905.]

JT, I thank you for this information, my welding instructor’s never told me this. Which .030 wire do you prefer, I currently use Hobart’s .030.

[@19cruella82]

Thanks man. Doing body work on my c10. I will be changing the leads this weekend. Still in the learning curve.

[@JTwelder.]

Awesome man!

[@liammurphy4383]

Great suggestion!....Just switched the polarity on my wire feed that i run on 220, it is like night and day, so much less spatter, and it cleans up super easy, Thanks for the tip

[@JTwelder.]

Right on!

[@clb62381]

Great video was wondering y my cheap harbor freight welder wouldn't weld right thanks keep up the videos

[@drakehauszx11]

Very informative, thank you.

[@nicholash8021]

I did my first weld today with a Titanium 200 and .30 flux wire, clean up the metal before I started, set the polarity correctly for flux core, used the suggested settings for the material I'm welding, and I had 10x more beads and even burn through. Once you get them, I learned you can't go over it because you can't get between the beads to clean the slag, so you just make it worse.

[@reloadnorth7722]

I have an Italian DECA welder (Decastar 150E) I bought from Princess Auto almost 30 years ago. This unit is second to none for flux core. I have a Lincoln mig-pak 180 for Gas welding.

[@brysonalden5414]

I've been trying to learn with an HF flux core welder and my results are exactly like your first test. I'm going to go check the leads and reverse them if needed, and maybe, just maybe I will finally get a weld that will hold. Thanks!

[@JTwelder.]

Yeah hopefully it that's your problem! It's a night and day difference you'll know if it worked.

[@brysonalden5414]

@@JTwelder. if only the guts of the HF were marked + and -!

[@JTwelder.]

@@brysonalden5414 yeah on cheaper models they probably don't bother with labeling that. Also Hobart makes probably the best flux core wire.

[@brysonalden5414]

@@JTwelder. Turns out, in my case, it was user error. I increased the feed rate, slowed down, and I'm starting to get decent welds. Thanks for your support!

[@kennethc8182]

​@@brysonalden5414Label once you figure it out.

[@Babylonbadders]

I've got a HITBOX multi-purpose welder, just switched the contacts around, and sure enough, much less splatter and way easier to get nice looking welds. Cheers!

[@daveross7]

I'm a self taught stick welder who's got hold of a MIG welder and how much easier is this, it had flux core wire and was set up wrong and since i found your video I'm now welding like a pro, just joking but my welds are 200% better. Thanks mate.

[@jerrywilder9403]

Thanks bud , give this a try 👍

[@stevop80_45]

Recently picked up a cheap 110v flux core welder, that is not able to be set up to run with gas. I bet it is also wired up like the gas version welders. I'll check the polarity next time I go to use it. Thanks for the tip!

[@samyish]

What an incredible difference! Thank you for sharing!

[@JTwelder.]

Glad it helped!

[@MrLightingstar]

Thanks for teach us buddy 😊👍🏻

[@mikepoint4717]

Fantastic video, I’m so happy I watched this . I’m inexperienced as they come it’s been since high school since I messed with a welder . I will apply with set up to my flux core welder when I get it . I just purchased a kicking horse welder . New sub here

[@JTwelder.]

Great to hear thanks for the sub!

[@davewallace5008]

In the UK we have mainly Super 6 both rods and flux core mig wire, not a great deal of choice really, but I find that I can weld pretty good with either, it's the 'make the best of what you've got' approach over here.

[@JTwelder.]

Wow. Over here in Canada we have rod and wire from all over the world readily available.

[@jeremytodd4906]

So do we! There are hundreds of welding shops in the UK that sell decent quality consumables, DIY shops usually only stock cheap no name stuff, look for a welding supply or shop online.

[@frankbenner8499]

I’ve recently been learning to weld and despite all the videos I’ve watched (and it’s a LOT!) I was frustrated by the spatter issue and porosity of flux core. I’m going to try changing polarity as you showed, and nobody else I’ve watched has mentioned. Thanks for this video, I’m really looking forward to trying this out!🤞🏼

[@jon4915]

This only works on more expensive flux core migs w/ a DC power supply, like his. That welder's over $600 The cheaper ones are AC and it won't make a difference. And that's why the cheap ones suck. Flux core itself is fine.

[@frankbenner8499]

Thanx for that info, my wire welder is AC only, and cheap lol. Maybe I should upgrade?

[@jon4915]

@@frankbenner8499 Yes. If I were to stick with flux core, I'd get the titanium from harbor freight. it has a dc power supply. much less spatter. use good wire also, the lincoln electric flux core is the best one. hardens quickly, a good thing if you are doing thin stuff like body panels

[@jon4915]

the next step up is a mig w/ dc inverter. w/ the cheap ac transformer ones, the power fluctuates a lot and doesnt give you a smooth weld pool

[@Joel-ki9my]

Im going out to check my welder now after this video. I bet I've been welding with it the wrong way this whole time.thanks for the information

[@dougnorton5143]

Thanks for the post. My welds look like your first past and I thought it was me just being out of practice. I used to be fairly decent for a part time welder. Just small projects, nothing elaborate or critical.

[@JTwelder.]

Glad to help

[@floydwilcox2640]

Great video, thank you.

[@kenw305]

Thanks! Great info

[@mikegeheren7508]

Thanks. Very good video

[@johndoe43]

Good video. People need to read the book

[@BrucePierson]

Here in Australia I have a 240V 100A flux core welder which I run on a 10A circuit. It must be set up correctly, because my welds look your second weld, not the first mess. I can get a few different brands of wire, but I think I prefer the Renegade wire over the Bosweld wire, although the Bosweld wire is still good.

[@todd1748]

same here mate. i use bossweld 100a gasless mig. pretty sure you cant change polarity if you wanted to

[@williamlindsay6502]

after fighting flux for years,this is the answer for all flux problems,i am welding 22ga with very little problems. hubba hubba.

[@mattwarrensocal]

What wire size you like?

[@awesomefish100]

I ran my machine improperly for about 4 years. My welds never improved what so ever and it made no sense. The minute I switched the polarity it looked like someone threw a stack of dimes on my workpiece.

[@royalknight4742]

My harbor freight titanium, 125 came set up correctly with the clamp positive!! Suprised me forsure!!!

[@JTwelder.]

Nice! I’ve been hearing that the titanium welders are very decent for the price.

[@Trashcan_Repairman]

Great video!!

[@sergiocantoli5783]

Cool! In retribution to your lesson I subscribed to you channel.

[@titanium87]

Great information Thank you! I don’t have a setup like that I only have one wire that’s bolted like that and that’s coming from the plug wire the other wires are on the other side and go into something wrapped around. Not sure if I can do this with mine. If anyone has any experience doing this with a 130 Mig welder from Amazon please let me know

[@madeinjapan3485]

Never knew this swapping the leads and so, ill definitely try it thanks.

[@JTwelder.]

Thanks for watching!

[@rogertaylor8615]

Very cool tip

[@steveashworth6707]

Great video!.

[@garycook4541]

Amazing! Thank you!

[@ClaremontClassicGarage]

Great video, Thanks!

[@carlsapartments8931]

great tip, I'm going to check my welder leads today and see about that, thanks. It's a cheap Canadian Tire 110 FC welder and I am almost positive they will be backwards plus I think it is running off a 15 amp circuit so these are a big part of why my welds look like that one you did or worse.

[@markyoungoutdoors2497]

Is this the one you bought? I’m looking for anyone with the same unit before I reverse the polarity. The wiring is not so simple as in this video. Yikes.😬 My unit is the Lincoln Weld-Pak 90i FC.

[@tyranducksworth1913]

Cool video it even sounds different too

[@northpoint1039]

Im really impressed here. Thank you big time for explaining what others tend not to do. I am thinking of getting into welding just as a DIY'er and I was really wondering about the power source for a 120v welder. Im wondering if you turn up the power on one of those 120v welders could you (or have you ever) blown the 20 amp breaker? You did a really good job explaining everything else and you have a great speaking voice. Kudos to you!! If I do decide to get into it I will burn what you said into my old brain :)

[@JTwelder.]

Yep I have blown the 20 amp breaker before. If your just welding sheet metal or bodywork a 120v welder will work but if your doing a lot of welding on 1/4” material and thicker that a 220v machine is definitely the way to go.

[@stevemcgowan3017]

hi.do you know on the settings is wire speed first knob on left and is it amps knob on right.im using 1.0 wire flux core on some bulkhead sheet metal .it was burning thru metal so turned both knobs down to minimum .i did have 0.8mm wire in machine at first but thought 1.0mm better for my van vw t4 camper.ive not welded on van yet just practising on bits metal 😊

[@johnverdin6600]

What size does the ground clap go to on the machine when you welding flux core + are -

[@russellsappliance2550]

I've got that same welder run 20 amp breaker and low gauge extension

[@terrencebuller7676]

Thanks for the tips. 👍

[@JTwelder.]

No problem 👍

[@carlsapartments8931]

I watched a video of a welder rating 5 or 6 different brands of FC wire and as I recall Lincoln scored on the low end and Hyanede scored on the high end, I don't remember all the brands he tested.

[@MaxenceGross]

Thanks for the tip. In my gasless fluxcore post, I can’t tell the polarity of the connexions, it doesn’t say + or -. How can I tell? Do you know?

[@mericksedlacek3651]

Thank you so much bro i just got this same exact welder helped alot to make surr what im doing

[@JTwelder.]

Glad I could help!

[@rage1868]

Wow. I really did not know that. 😮 Thank you. All this time. 😅

[@spaceman9931]

FCAW-S = Self shielded flux-cored arc welding and FCAW-G = Gas shielded flux-cored arc welding if anyone was wondering.

[@onezeroone354]

Thank you!

[@thomashetherington8532]

I have an older Craftsman 125 that when you open up the side cover, there is a label stating where the cables are to be attached for welding mig wire and gasless flux. Flux wire in my opinion still gives you a poor weld compared to running mig wire with gas and set up correctly.

[@BmwolotlE90]

What if the machine doesnt have this option, under the panel on my machine just has the gauge and speed setting sticker and the spool/tensioner but no cables to swap polarity, unless I have to open up the machine lol

[@borisjohnson1944]

The instruction for my welder explained this set-up. I am not a welder by any stretch of the imagination. But at least my machine is correctly wired.

[@andrewrobinson2869]

I have a sca mig welder unfortunately after opening it up to transfer the wire I noticed they have hard wired so it’s not like yours where you can just undo a lock nut. Can I cut the wires then either solder together but they might get hot or buy 2 joiners that I could use, any advice is appreciated, I live on a disability pension so I can’t afford a better welder , I also live in Australia so it’s 240 v. Cheers Andy.

[@robchesley4591]

Ok, I have a titanium from H F . if I make this change do I still run the suggested setting for flux core on steel (electrode neg)

[@danielgarcia6416]

I just bought an entry level welder (arccaptain 130) it uses both wire and stick. How will changing the polarity affect the stock welding?

[@homesteadhandyman4481]

Thanks !

[@pjhorn5307]

Do you know if the titanium flux 125 from harbor freight need this done? And if so do you know how to check? From the factory the gun cable is connected to the main electrical board in the machine. The cable connections are labeled + or -

[@anthonyguy1347]

I have a Jegs Mig 100 gasless flux core welder. It spatters like throwing paint at a spinning fan. The gun and ground are hard wired to the transformer, so I see no easy way to reverse the polarity without butchering the machine. Any suggestions?

[@maravillosonene99]

I will try this tomorrow I just bought a flux gasless yesterdayand I was practicing last night and I was so disappointed and I thought it was me I had spatter everywhere and no penetration, I really hope I see changes tomorrow thanks!

[@gannonw]

Dumb question - I have the titanium 125 FC welder from Harbor Freight. It can only do FC so it should be set up correctly right?

[@JTwelder.]

Yeah a few people have said that the Titanium machines are set up correctly

[@georgebonney90]

If you buy a Hobart handler 140 its set up properly,from the factory, for flux core.

[@theywillknowbandcook1279]

Can this be done on a Chicago Electric flux welder, I’m not seeing an easy way to switch polarity?

[@davebender8901]

Any recommendations of generator size I would want to buy for this? I really don't want to use household lines for it.

[@tnmonty501]

Yeah I sold one years ago because I had no idea about the polarity

[@Crazy5150760]

i bought the cheapest titanium flux core welder from harbor freight and mine was set up properly. maybe the Chicago electric is set up with negative ground but mine is positive ground

[@GarageBandDad]

Ok. My ground is hooked up to one end of a cylindrical element that has the continuation of the ground coming off the other end and its secured into a heat sink that is attached to a circuit board. The gun comes up through the top, feeds down to all the motor area and is bolted straight to the circuit board. There is nothing indicating which is positive and which is negative. I’ve got the Lincoln weld-pak 90i FC. Any suggestions? Edit. It appears two wires that make up my gun are connected to areas marked out- and my ground is connected also in both places marked out + Does this seem right?

[@Jackmanis]

Thank you. Great tip. What wire do you recommend? I using a Miller-matic-735 M/T

[@JTwelder.]

I recommend the Hobart gas-less flux core wire.