Flux core & shielding gas

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I just read a short article on the web that said flux core wire welding is enhanced by using a shielding gas such as the 75/25 mig mix. I am a complete newbie and had never heard that. What would the benefits be?
Reply:I have use gas on self shielding wire only as an experiment and to help chase down problems. That is the only reaso to ever do it. Self shielding wire was not made to be using shielding gas ever. The weld engineers will not approve any use of gas on self shielding flux core. It gives the weld chemical and mechanical properties that they did not intend. It would be ok to play with, but I would be very leary of doing it on something important as you just don't quite know how it will react. A quick email to Hobart Brothers or Lincoln would confirm the "do not use part".Gas shielded flux core is a different story. It is specifically made to be used with shielding gas. It will not work at all without it.
Reply:I can't imagine it would hurt things, but I doubt there would be any benefit. The flux does 2 jobs; it creates the shielding properties that a gas would do, and it also is chemically cleaning the weld area as you go. That is why fluxcore is recommended on dirty steel, or stick welding. No gas can do that. I would say if you run gas while using fluxcore, you may blow out the shielding that is created by the flux melting. That would possibly lead to porosity. But you can try it, and post up pics if you'd like.And then, after so much work...... you have it in your hand, and you look over to your side...... and the runner has run off. Leaving you holding the prize, wondering when the runner will return.
Reply:Self shielded wire has that name for a reason. It is SELF SHIELDED. It is intended to be used as such.DDA52 gave a clear explanation that was easy to understand.
Reply:Thanks for clearing that up for me. Otherwise I'd probably be doing it.
Reply:Using shielding gas with FCAW-SS wires is fine, and may improve the arc stability, and if anything, < 20% CO2 / argon mixtures will only improve properties. You can run self shielding wires like NS3M to 3.2mm under SAW flux also.However it is a waste of money, so if higher quality welds are required, go with dual shield FCAW, MIG etc.FCAW-SS wires are notorious for poor CVN properties and high HV values, I believe NR-232 is best if these properties are desired. For the back yard flogger FCAW-SS as it's intended is fine.Cheers
Reply:Originally Posted by hvwI just read a short article on the web that said flux core wire welding is enhanced by using a shielding gas such as the 75/25 mig mix. I am a complete newbie and had never heard that. What would the benefits be?