[dfarning]

Last week, I got a box of ER70S-2 filler rod to see how it would work. So for the last couple of days, I have been switching back and forth just to see the differences. I am mostly practicing butt joints and lap joints on thin sheet. The machine is set for 50 Amps. DC. 1/16 filler and 1/16 thoriated tungsten. I flap disk the weld area to bright and shiny. Then wipe with acetone.

With the -2 filler I see short burst of sparkles as the puddle moves forward. This is pretty infrequent. Maybe about one every 9-12 inches of bead, but enough to be noticeable. Strangely enough this doesn't happen when I use the -6 filler.

Is this an effect of the additives in the filler? Is it harmfull?

David

[Artie F. Emm]

Just to set aside one variable, do you wipe down the filler rod with acetone too? I always get black streaks on the rag.

[Coldman]

I've heard it's the aluminium in the rod that does this as it scavenges oxygen from the parent metal. Don't know if its true.

[Poland308]

I think the rod is probably the least of the worries. How thin is the sheeting your welding on? Is it possible what your seeing is at a point were your getting full penetration and pulling mill flake all the way through the joint? Is there signs that you were about to burn through the parent metal? I.E. melted spots on the back side. Some times on very old pipe were the metallurgy may have been less than current standards you will see what you are describing or if the steel is literally embedded with a chemical like at a some of the places I work. I was told by a much more experienced welder that the DCEN process will actually pull contaminates up to the surface due to electron flow. Not sure about that but I have seen slag float to the top of a molten metal pool in other applications.

[dfarning]

Yep, It was schmutz on the back side. I was practicing on 18-20 gauge sheet.

Specifically, there was some pitting on the back side of the scrap I was using for practice. After cleaning the back side of the material with a flap disk followed by acetone wipe the sparklers are gone.

Thanks again.

David