change polarity for fluxcore?

GMAW/MIG is dc-. FCAW is dc+. your machine is already set up for flux core.

Some flux core wires run DC-, some run DC+. The majority are DC-

JTMcC.

??? I'm not sure what Nathan is referring to because I believe he is a seasoned weldor, but... For GMAW/MIG the gun is wired positive. I've heard there's some fluxcore or dualshield FCAW that uses gun positive but mostly FCAW is gun negative. See

Nevertheless, I suspect Nathan is right in that your machine is already wired for fluxcore. I've not seen a MIG only machine but I've seen plenty of FCAW only machines. Yours may be the exception.

As for Henning's question, you won't like FCAW with positive polarity. I don't like the idea of chopping the machine up unless you do it so that you can change polarity back and forth easily. Can you get rid of this machine and get one that suits your needs?

my apologies. in haste i got my terminology mixed up. GMAW/MIG is done using REVERSE polarity, DCEP. FCAW is done using STRAIGHT polarity, DCEN. as stated earlier, i suspect the machine is already set up for FCAW flux core.

It's not that cut and dried, there are flux core wires that run DC+, and some that run DC-.

JTMcC.

youll also find GMAW wire that requires straight polarity (e70u-1) but its as rare as reverse polarity for fcaw. if the original poster were using such a rare consumable he probably would have mentioned it.

Lincoln NS 3M wire can't be described as "rare". It's in probably every steel building or bridge built in the last 20 years. A friend of mine buys it by the pallet. Anyway, those blanket statements are dangerous. Your statement "FCAW is done using STRAIGHT polarity" is missleading. It's done both ways, frequently.

JTMcC.

i seriously doubt that anyone preparing to weld anything structural would be doing it on a machine such as the original poster described. youre looking at everything that is _possible_ and i am looking at everything that is _practical_ for this particular thread.

besides, if my blanket statements are "dangerous" then you should contact lincoln electric and correct them as they have made the _same_ blanket statements.

from

"(GMAW) as identified by the American Welding Society, is also popularly known as MIG (Metal Inert Gas) and uses a continuous solid wire electrode for filler metal and an externally supplied gas(typically from a high-pressure cylinder) for shielding. The wire is usually mild steel, typically copper colored because it is electroplated with a thin layer of copper to protect it from rusting, improve electrical conductivity, increase contact tip life and generally improve arc performance. The welder must be setup for DC positive polarity." (although we've already discussd e70u-1).

I'm sure the OP isn't going to be running .120 NS-3M wire in his machine, but then I really don't know what types of wire he may end up trying. I certainly don't have any idea what wire everyone else reading this thread has or will use. But the fact remains that flux core runs both ways, period. Your statement made it sound as if all FCAW is done DC-, or DC+ depending on which post we use as an example. I have pointed out several times now, and this will be the last, FCAW is often done DC- and it's often done DC+. If your answer only addresses those things you deem "practical", maybe it would help to say so in the answer, or throw in "some of the time" or "most of the time".

JTMcC.

Alright, all you welders ................ question ...............

Is there any welding process that uses ONLY ONE polarity?

That is to say the other one is NEVER used?

I don't have the answer. IMHO, the polarity can be reversed in any process, it just affects the penetration, etc. Some rods can only be used in a particular polarity, but I think one could adjust the amperage or a lot of things to at least make the thing work, even if you got an unsatisfactory unsafe weld. I never tried a 7018 on straight polarity. Would it just melt off, and it would be like working with wax dripped from a candle? I don't know.

Opinions and experiences, please................

Steve

henning wrote: .(clip) It turned out the machine is permanently set for positive polarity. I will have to cut the groundcable and add some extra wirelengt and and splice the wires in reverse(clip) ^^^^^^^^^^^^ Why in the world would ANYONE build a machine in which the polarity is so hard to change?

Because they designed the machine for ONE purpose and figured anyone who bought it would use it that way?

Just a guess.

Steve

To clarify: The machine is designed for using gasshield. I dont know how long fluxcore has been availlable. My guess is that this is a somewhat old machine. The manual makes no mention of fluxcore. I suppose I will have to do some destructive tests to see what the results are Thanks for the input Henning

>

has been availlable. My guess is that this is a somewhat old machine. The manual

Just keep your PPE on, and a fire extinguisher handy.

STeve