Using finger to walk cup

By swsweld (****)

Date 03-10-2009 02:18

I don't think there is any hard evidence that the cup walking technique will cause the weld to fail due to ceramic contamination.
No industry I've worked in prohibited it. (nuclear, boilers, chemical, refineries, trash burners-miss those trash burners). I have been told as you have that the potential is there I just have never experienced it on jobs I've worked.

By pypLynr (***)

Date 03-10-2009 05:12

If you apply the technique PROPERLY ... contamination would be extremely unlikely . Light pressure applied to your 'rig' while walking the cup is the right way ... alot of guys push hard , increasing the risk of contamination and also increasing premature failure in the 'rig' head . This is another reason I polish the edge of my cups with a tiger disc . Makes them super slick and they won't hang up . Just my two cents .

By Kix

Date 03-10-2009 13:15

When your walking the cup, your walking it back on the solidified weld metal so there is no way you can contaminate the weld while doinf it right. Even if you slip, there is slim to no chance of contaminating the weld puddle. The ceramic doesn't melt and fuse with the liquid steel, it more or less leaves a foot frint in it, kind of like a foot print in concrete.

By spgtti

Date 03-12-2009 00:13

Its not walking the cup if you don't touch the pipe, its called free hand.

By fbrieden (***)

Date 03-12-2009 04:30 Edited 03-12-2009 04:46

Gentlemen,

I was going through my memory banks, and the free hand method described was called "the Dunbar glove' or "the Dunbar method". It was developed by a welder named Dunbar, years ago. Whomever he was, he was employed by either Dupont, or Dow in their sensitive research areas; I believe it was Dupont. My welding instructor in 1974 emphasized that technique, back then it was TIG, to avoid contamination (so he believed). Your glove index finger, with extra insulation, rested along the joint and slid while manipulating the torch with your other fingers, while your other hand fed the filler. This non contact method, due to it's manipulation progression was termed "walking the cup". Full joint contact with the torch is true walking the cup, and steadier! Not bragging, but I can still do both and get that "sideways hour glass" appearance!

By Kix

Date 03-12-2009 12:57

I have thimbles I use on the end of my finger when I have to use the Connolly method. ;-)

By arrowside (**)

Date 03-12-2009 15:47

If ceramic backing doesn't contaminate the weld, why would a ceramic cup that's not even in contact with the puddle? I realize that all ceramic isn't created equal, BUT??

By vagabond (***)

Date 03-12-2009 16:33

I've heard from quite a few guys who were Navy welders that no contact was allowed with the cup either. I don't know if they've gotten away from that or if it is still in effect.

By pipewelder_1999 (****)

Date 03-12-2009 17:14 Edited 03-12-2009 17:20

There was no walking the cup ever talked about one way or the other except for putting a root in a U groove joint with a consumable insert in 027.

We didn't even hear of it but most of the stuff I welded on boats didn't lend itself to walking the cup other than the easy side. And even then it was restricted. All WP-9 or WP-26 torches. Never saw a WP-17.

By JeremyW83 (***)

Date 03-14-2009 18:25

I know what free handing is and what this guy described sounded close but not quite. You also have to take into account that this happened close to 20 - 25 yrs ago w/ KBR down in La Grange.