Using Flux core in welder set up for MIG??

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If you have a MIG set up for gas (polarity correct, argon, CO2 mix) and you push flux core wire (as if you were set up for no gas), will the welds turn out as good as if using the correct wire?thanks
Reply:Beter than using flux core no gas, but not as good as solid wire and gas (slag mess). But the flux core will help with penetration some on a smaller machiene. My take on it anyway.Lincoln PT185 TIGLincoln 175 MIGLincoln 240 amp AC StickLind Needle Arc plasma welderPlasma cutter, soon???
Reply:Um, no.  Flux core (at least the type you probably have) is meant to be run with no shielding gas...period.  Also, you need to switch the polarity to DCEN or you will end up with swiss cheese welds.  Lastly, don't push self-shielding flux cored wire.  It is a bad habit and the welds will not be as strong as if the wire is pulled (dragged).
Reply:Point taken on not pushing, forgot about that dead brain cells. But have you tried just turning the gas on a bit while running flux core? My experience it cleaned up the weld nicely vs. flux core no gas. Certainly don't need to, but just to run a cleaner bead on some heavy material with a smaller machiene seemed to work.Lincoln PT185 TIGLincoln 175 MIGLincoln 240 amp AC StickLind Needle Arc plasma welderPlasma cutter, soon???
Reply:It may look and run nicer, but it messes with the chemistry of the weld metal in a way that the manufacturers did not intend and might lead to serious defects or discontinuities.  If you have the proper settings and technique, it runs just fine with out gas.  If you seriously have the need to run gas with flux cored wire, then purchase flux cored wire that is meant to be run with shielding gas.
Reply:Humm,  OK, I'm new to this forum, fairly new to MIG welding (small projects years apart for the last 10 years), and have never had any training or hung around welders so when I said "push" I was talking outta my rear...I was just refering to the fact that my mig welder pushes the wire into the liner from the friction wheel in the unit.   I gather the proper use of "push" is the direction of the weld "into" or "out of" the molten pool of steel.  Also, I had set the polarity up for gas (as shown in the welder diagram), when did the switch over from flux core settings.  I just wondered If I could avoid switching the wire but just laziness on my part.  Now, as far as "the chemisty" of the weld....I was under the assumption that the shielding gas was only there to keep oxygen away from the weld to prevent oxidation.  I also assumed that the flux in flux core wire, somehow, performed the same function by gassing some non-reactive gas and keeping oxygen away.  So, I take it I'm mistaken about how and why gas is used. I dont NEED to use the flux core wire with the gas, I just wanted to use up the wire if it was not an issue.   I have always used solid wire and gas and am used to the welds I get and my method so I'm sticking with it.   Last time I tried fux core I kept touching the tip to the work....the MIG gas diffuser/shield helps to keep the tip from touching.  I need to work on my control....LOLLast edited by kb9nvh; 09-25-2008 at 10:04 PM.
Reply:The shielding gas does keep the oxygen away from the molten weld puddle.  The flux in self-shielding flux cored wire does that and more.  The ingredients of the flux also have chemicals that help to change the properties of the weld metal and give it more strength, hardness, or whatever the spec calls for.  That is one of the reasons that flux cored wire is more versatile than solid wire.
Reply:Its weird to me that polarity makes a difference ....I'm an electronics guy and "hole flow" VS "electron flow" was just a matter of a negative or positive sign in the math and it made no difference what convention you used....I would be interested in the physics involved in the process.  Any threads to refer me to?
Reply:If you have 'plain' fluxcore wire, it is made to be used without gas.  The fluxcore wire is pretty much like a stick electrode except that the flux is on the inside of the wire instead of on the outside of the stick.The flux does act as the shielding to keep the air (and thus the oxygen and other atmospheric gases) away from the arc and the molten metal.  The flux also interacts with the molten metal and the arc to do other desirable things, like take care of mild amounts of 'gunk' in the welding zone and make the weld turn out, metallurgically, as desired.There are also some fluxcore (or other 'core') wires that are made to be used WITH gas shielding.  Those wires use the combination of the flux (or other 'filling') inside the wire and the gas shielding to make the weld turn out as desired metallurgically.And different wires may use different polarities.  Check the label or catalog or literature and use the correct polarity.  With the wrong polarity, the weld will be 'wrong' to varying degrees.Different wires have different procedures and different properties and different results.  The best laid schemes ... Gang oft agley ...
Reply:Don't try to reinvent the process. Do what the engineers before you (for decades) recommend. I gave up fighting the establishment a long time ago. I have more important things to discover. IMHO, YMMV 9-11-2001......We Will Never ForgetRetired desk jockey. Hobby weldor with a little training. Craftsman O/A---Flat, Vert, Ovhd, Horz. Miller Syncrowave 250
Reply:Yuip,  thanks for the quicky lessons on welding/flux/gas and all.   I dont intend to go against well established methods (that is why I asked in the first place) but I might like some technical references for my own edification.  I now understand that wire is  not just wire but a type of metal with the types of properties needed to create a good strong weld.  Flux, in addition to help shield oxygen from the weld, also is there to add properties to the metal that are beneficial (whatever those benefits may be).  I also understand that MIG is not always better than Flux core welding but each has its advantages and if your making your living at this stuff and preventing others from dieing (ie roll cage, amusement park ride welds, vehicular welds that effect structure and drivability), then you better understand what and why.  I try to stay away from welds that, if fail, could kill someone (and I'm sure society appreciates it too..LOL). Originally Posted by Craig in DenverDon't try to reinvent the process. Do what the engineers before you (for decades) recommend. I gave up fighting the establishment a long time ago. I have more important things to discover. IMHO, YMMV
Reply:Guilty as charged I guess.It may look and run nicer, but it messes with the chemistry of the weld metal in a way that the manufacturers did not intend and might lead to serious defects or discontinuities.
Reply:kb9nvh you might try Lincoln's website for more info on the pos - neg thing and why it matters. I am a welder and not an electronics guy but do understand electron flow. It has a lot to do with heat concentration. DCEN (electrode negative) concentrates the heat in the base material and DCEP (electrode positive) concentrates the heat in the electrode. That's the reason why DCEP tends to vaporize tungsten in the GTAW process at any kind of amperage (I used that because it is a very dramatic illustration when witnessed in person. This event is usually followed by a lot of cussing, LOL). That's the basics and the physics get reeeeeal complicated when you start using alloys and adding fluxes to the mix. I use both GMAW and FCAW frequently and the biggest difference I have seen is that the particular flux cored wire I use has much more dig than bare wire and gas. Just my observation. Since I didn't get my education in physics or any other heavy duty science I just go with the manufacturers recommendations because I figure they know a whole lot more about why they made them than I do, lol, and it leaves liability with them and not me.Last edited by Oldtimer; 09-26-2008 at 04:34 PM.Reason: left something out
Reply:Originally Posted by Oldtimerkb9nvh you might try Lincoln's website for more info on the pos - neg thing and why it matters. I am a welder and not an electronics guy but do understand electron flow. It has a lot to do with heat concentration. DCEN (electrode negative) concentrates the heat in the base material and DCEP (electrode positive) concentrates the heat in the electrode. That's the reason why DCEP tends to vaporize tungsten in the GTAW process at any kind of amperage (I used that because it is a very dramatic illustration when witnessed in person. This event is usually followed by a lot of cussing, LOL). That's the basics and the physics get reeeeeal complicated when you start using alloys and adding fluxes to the mix. I use both GMAW and FCAW frequently and the biggest difference I have seen is that the particular flux cored wire I use has much more dig than bare wire and gas. Just my observation. Since I didn't get my education in physics or any other heavy duty science I just go with the manufacturers recommendations because I figure they know a whole lot more about why they made them than I do, lol, and it leaves liability with them and not me.
Reply:Ok, will do.  I need to check what wire I'm using...its .035 but I was sure it was solid core...my chart only shows that thick of wire as flux core.  listed as NS115 Copper free, heat 67136  size 0.035I'll go check the lincoln site to see if I'm using the right stuff.