Wire Weld w/ A/C?

I'm speculating on this because I don't remember hearing or reading about why AC isn't used. One of the advantages of DC output stick welders is that the uninterrupted current does not cause a problem maintaining the arc. AC stick welders are subject to the current going to zero at same cyclic rate as the power supply. Stick electrodes contain arc stabilizers to deal with this problem. Electrodes which aren't specifically intended for AC welders can be extremely difficult to use with a low open circuit voltage AC welder, or with any AC welder at amperages normally used by non-industrial users. You only have to try to weld with 6010 or with regular (non AC) 7018 with an AC welder to see how much difference DC makes.

Regular wire feed welding uses a solid wire and shielding gas. Although different gases have different current carrying capabilities---Argon carries current much better than CO2, for instance---it may be that no gas has the ability to serve as an arc stabilizer, or to do so without compromising the shielding function. Arc stabilizers could probably be added to flux core wire, but wire feed welders that run flux core only are not particularly popular anyway so there would seem to be little market incentive to do so.

I'll watch with interest to see what the real answer is.

All the best, Stan

Most if not all other alloys use DC

Also the type power supply for wire welding is something called "constant voltage" where the amperage is controlled by the speed of the wire while the machine keeps the voltage the same.

which is not like a stick welder where the amperage is adjusted,and kept at a "constant current" and the voltage might vary.

This is generally why a wire feeder can't just be attached to a stick welder.

You might get a chance to view a late model welder with both C and CV settings.

As for running aluminium wire, I have always used DC straight,.030 or .041 hard alloy wire, with 100% argon at a high flow rate.

We once experimented with 75/25 gas with aluminium wire on some scrap aluminium before changing over gasses, just to see what it would do. It was way too HOT. It just burned through the material and was extremely dirty.

I'm with the AC/DC/CC/CV stuff and have several different machines that throw from any to everything. My little crackerbox I have mounted in the barn for quick patch jobs is an AC only machine. I have a wire feeder (spool gun), with its own contactor, gas valve and speed control box, that is not dependent on the welding current to operate the wire feeding functions. I originally set it up to run off a portable unit with no remote feature for one particular large outdoor aluminium job. The feeder drive is totally isolated from the welding power. I keep wondering what would happen running that feeder with AC besides a little less penetration and maybe more splatter.

I guess maybe the only way to find out is to hook it up and pull the trigger.