Correct Polarity for Dual Shield?

imagineer · #1 04-26-2016, 07:47 AM

I'm preparing to do some frame patching on a Jeep TJ and although I'll make the effort to clean all the existing frame metal, there will still be some rust left behind.

As such, I'm planning on switching over to flux core for the project (and will set my welder to DC- accordingly).

I've seen welders at my plant performing welds using both flux core and shielding gas (I assume 75/25). They said it was to create a hotter weld and also reduce spatter.

So, the question; when using Flux Core and Shielding gas, should the welder be set for DC- or DC+?

Shade Tree Welder · #2 04-26-2016, 08:22 AM

Generally dual shielded wire is DC+, but there is the occasional DC- wire.

What wire are you running?

Mostly they run 100% CO2 for cost in production but you can run argon/CO2
mixed, again wire dependent.

http://www.lincolnelectric.com/en-us...ultracore.aspx

MAC702 · #3 04-26-2016, 09:29 AM

The way I'm reading it, you are planning to use common self-shielded flux-cored wire, but to use a shielding gas anyway. And while I've done this, and not seen any advantage, you will still use the correct polarity for the wire, DC-.

imagineer · #4 04-27-2016, 10:01 AM

Quote:

Originally Posted by MAC702

The way I'm reading it, you are planning to use common self-shielded flux-cored wire, but to use a shielding gas anyway. And while I've done this, and not seen any advantage, you will still use the correct polarity for the wire, DC-.

Thanks, that's the info I needed.

I'll still set up a series of practice pieces and try out both polarities, with and without shielding gas to see which offers a better result.

WeekendWarrior · #5 04-27-2016, 11:17 AM

I'm a noob, so correct me if I'm wrong, but I thought running gas shielded flux core needs wire made for that, not just "regular" FC wire?

Lincoln, for example, sells their "outershield" wire for this purpose, whereas their "regular" FC wire is called "innershield".

Shade Tree Welder · #6 04-27-2016, 11:30 AM

Quote:

Originally Posted by MAC702

The way I'm reading it, you are planning to use common self-shielded flux-cored wire, but to use a shielding gas anyway. And while I've done this, and not seen any advantage, you will still use the correct polarity for the wire, DC-.

Quote:

Originally Posted by imagineer

Thanks, that's the info I needed. I'll still set up a series of practice pieces and try out both polarities, with and without shielding gas to see which offers a better result.

Hey, if your really going to run shielding gas on gasless flux core wire, do me a favor instead of wasting your money on gas that is not needed just mail me the money instead of spending it at you LWS. You will gain nothing using gas on self shielded wire. It is a really stupid idea.

weldor2005 · #7 04-27-2016, 11:56 AM

Quote:

Originally Posted by Shade Tree Welder

Hey, if your really going to run shielding gas on gasless flux core wire,
do me a favor instead of wasting your money on gas that is not needed
just mail me the money instead of spending it at you LWS.

You will gain nothing using gas on self shielded wire. It is are really stupid
idea.

I will take a piece of this pie.

Shade Tree Welder · #8 04-27-2016, 02:43 PM

Quote:

Originally Posted by WeekendWarrior

I'm a noob, so correct me if I'm wrong, but I thought running gas shielded flux core needs wire made for that, not just "regular" FC wire? Lincoln, for example, sells their "outershield" wire for this purpose, whereas their "regular" FC wire is called "innershield".

You got it.

Sent from the great beyond...