Understand that you have to change polarity when you change from flux-core to solid w/gas on my mig - but what polarity do I use if I use gas with my flux-core? Trying to get both of both worlds. Thanks
In my opinion using gas with flux-core wire is a waste of gas. The flux will create its own sheilding gas so the sheilding gas you supply is worthless. You will still have spatter, You will still have slag to clean off and you will not get any more penitration.And the biggest reason to use the flux-core wire is so you can weld out in a windy inviroment and not get porosity in the weld and also not having to carry a bottle of gas with you when you do the field repairs.
If your flux core wire requires shielding gas (dual shield or outer shield) must use shielding gas.
If your flux core wire is self shielding called inner shield by Lincoln Electric then using shielding gas is a waist of money but probably doesn't damage weld.
Look at specifications for your wire from the manufacture or cross to equivilant using AWS wire designation to know if wire requires shielding gas.
There are two types of mild steel flux cored wire in AWS classes EXXT-XX
E = electrode
X = tensel strength (7=70,000 / 8=80,000)
X = position (0=flat and horizontal / 1= all position)
T = tubular (flux or metal cored wire)
XX = type of shielding gas, usability and preformance capability
1. Self shielding (trade names- refered to as fabshield or innershield). In the 2# and 10# spools with .035 and .045 sizes most welding supply stores only stock E71T11 wire wich runs on DCEN without shielding. Why purchase a self shielding wire and then use shielding gas ?
There are several AWS classes of self shielding wires and you need to know what you have to use it properly.
T-3, T-4, and T-6 run on DCEP but are normally prefixed with
E70T-X which indicates flat and horizontal positions.
T-7, T-8, T-10 and T-11 run on DCEN but are nornally prefixed with E71T-XX which indicates all position.
2.Gas shielded (trade names- refered to as fabco, dualshield, or outershield). In the 2# and 10# spools with .035 and .045 sizes most welding supply stores only stock E71T-1 wire which runs on DCEP with CO2 or C25 shielding gases.
Consult suppliers recommendations for application, shielding gases, current, and electrical stick out on any wire.
Gas shielded flux cored wires typically produce less spatter and fume (smoke) than self shielding wires.
I have watched this subject come up several times and I think there is confusion between dual shield and people wanting to use flux core wire with gas. True dual shield is a amazing product and has wonderful cababilities. I see welding on as thick of metal as 2-3 inches using .045 at over 400 amps using engine drives and large power supplies both in the construction industry and in the ship building trade. I live in San Diego and have been on the National Steel and Shipbuilding property repairing heavy equipment and have watched them welding the heavy side plates on extremely large ships using dual shield right on the bay in the wind with very little tenting. Dual shield also has the ability to be allmost completely slag free and gives the most beautiful welds you ever saw. I also know that a lot of dual shield uses the same polarity as hard wire so manufactures literature should be consulted before using to check for proper gas and polarity as well as which dual shield should be used for which alloys.