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TIG on mild steel. 3F noob issues walking the cup.

Posted: Wed Apr 16, 2014 1:29 pm
by theglassshroom
Okay, so I'm at the end of my first semester, and we're working on vertical fillet, as this will be our final exam. We're supposed to lay a root, a hot, and three stringers. Now my root and my hot pass are pretty decent. I'll post a picture of my hot pass just 'cus it's perdy. My issue comes after that. When running my stringers, I'm having a hell of a time walking the cup. It seems that most of the time, I can't get any purchase on the metal, and either end up walking in place, if you will, or I end up slipping. Another issue I'm having is that even though I've got my tungsten right over my puddle, my filler rod keeps balling up, and that clearly ends up making my puddle way too big once it gets introduced. I'm mainly referring to doing lay wire, but I also tried dipping, and it was acting in a similar manner.

Amperage: 130
3/32" er70s-2 on 1/4" mild steel

https://scontent-b-iad.xx.fbcdn.net/hph ... 8420_n.jpg

Re: TIG on mild steel. 3F noob issues walking the cup.

Posted: Wed Apr 16, 2014 7:56 pm
by Otto Nobedder
I think I see two things happening here.

Once your root and 1'st fill are in, your cup now has to "walk" across the bead, instead of just one side of the fillet to the other, and you will need a very light touch to walk it. It's easy to bear down too much when you're only touching the sides.

The other thing I suspect, is you need less "stick out" for the cap passes, so you're closer to straight in. Excessive stick-out will push the heat in front of you (because of the angle you have to carry), and cause the "ball-up" issue.

Without pictures of the problem area, that's my best guesses

Steve S

Re: TIG on mild steel. 3F noob issues walking the cup.

Posted: Thu Apr 17, 2014 1:19 am
by weldin mike 27
That sounds good to me Otto, knowing what i know about full tig, (sweet f#$% all) i would try to walk the first beads, root and hot, then free hand the rest, or just rest the cup edge on the job, for stability .

Mick

Re: TIG on mild steel. 3F noob issues walking the cup.

Posted: Thu Apr 17, 2014 7:29 am
by theglassshroom
I suppose all of that makes a lot of sense. I appreciate it, gentlemen.

Re: TIG on mild steel. 3F noob issues walking the cup.

Posted: Thu Apr 17, 2014 10:08 am
by Wes917
weldin mike 27 wrote:That sounds good to me Otto, knowing what i know about full tig, (sweet f#$% all) i would try to walk the first beads, root and hot, then free hand the rest, or just rest the cup edge on the job, for stability .

Mick

This is how I would do it also

Re: TIG on mild steel. 3F noob issues walking the cup.

Posted: Thu Apr 17, 2014 11:52 am
by mcoe
Seems like it is time for someone to buy a tig finger if they haven't already. :lol:

Re: TIG on mild steel. 3F noob issues walking the cup.

Posted: Thu Apr 17, 2014 1:47 pm
by theglassshroom
I've got a tig finger, and I use it when starting my bead, however my instructor is adamant about us walking the cup on all but the beginning of the bead.

Re: TIG on mild steel. 3F noob issues walking the cup.

Posted: Thu Apr 17, 2014 6:39 pm
by Otto Nobedder
Here's a trick an old pipewelder shared with me, to learn the "soft touch" for walking over a bead.

Strip the label off a two-litre soda bottle. Use your pipe wrap and a sharpie to draw a line. With an old, dead tig torch, cup of choice, and tungsten (leads aren't needed, but a short whip to simulate the weight helps), just sit and walk the cup around the bottle. Stick the neck in a vice, or just hold it on the coffee table with your off hand. If you're denting the bottle, your touch is too heavy. The plastic is slicker than any metal you'll likely weld.

You won't likely master this. (No one does.) It trains muscle memory.

If you can find a bottle with a "step" above or below the label, walking this will be more like walking the crown of a cap .

Just a though, if you have the patience.

Steve S