Toysrme

yeah, i had talked to someone that i know can do it over the last little bit and i know you need to use a backside flux and either a stainless flux tig rod or special frontside flux. weld it in small portions at a time.

mopar318

More info on stainless flux tig rod. I have never seen/heard of it?

Toysrme

there are lots of ER flux rods avalible. You just have to make sure the flux does not get under the weld post root-pass. They're used for root-passing pipe when a backpurge is not viable. ASME FTW.
R308LT1-5, R309LT1-5, R316LT1-5 & R347LT1-5
Same basic classifications as SFA-5.3 & 5.9, etc

mopar318

Intersting.

So say I am welded schedule 40 pipe, instead of back purging, I could do a root pass with flux cored stainless rod?

And then do a weave pass with filler with regular 309 filler rod?

Toysrme

If you wanted but note that is NOT a SMAW (stick) flux electrode. Those are ER. This is a non electrode filler rod designed to root pass tig. Rxxxxxx
Also note that the backside should still be purged if it's in the HAZ.

Toysrme

It's also likely much cheaper to gas-purge the backside with normal rods. Talking almost no argon flow VS paying more money for flux rods - that wont deposit as much material.

mopar318

Yeah, I figured its cheaper to just back purge. I was trying to get the basics of what the Flux rod is used for. I read up a little more on it and it seams as though its used in larger pipe line welding.

Toysrme

there's all kinds of flux gtaw rods and gas rods. not just stainless. used for all kinds of stuff.