Many plants do indeed not allow walking of the cup. On sanitary applications, such as stainless food-grade and pharmeceutical lines, prints and P&ID's specifically prohibit this method. The ceramic material of the cup becomes entrapped in the weld, thus compromising the integrity of the weld, sanitary-wise and strength-wise.
For a beginner, I would definately learn free-hand first. Once you have become well-versed in holding a steady arc and feeding filler wire at a constant rate, you can start fooling around with different ways of holding the torch, as well as walking the cup. I would also practice welding while holding the torch in your non-dominant hand. It is a real lifesaver when you are in a pinch (I probably do 50/50 of my in-position welds between my right and left hands).
Just my .02 cents.
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Good answer Clint. I have heard that in some sanitary applications walking the cup is not allowed because of pieces of the shield cup can actually get entrapped in the weld puddle. Seems I heard that some years ago.
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Walking The Cup Is A Tool, Not A Method
The "other method" is referred to as free-hand. Walking the cup is a tool, not a method. It is often used in conjunction with another tool known as "chasing the wire", where the filler metal rod is pre-placed in the weld groove prior to or as the arc is struck. Walking the cup is acceptable in certain situations and not acceptable in others; it depends on what the CWI and/or engineer specify. Walking the cup is a tool that allows, to some degree or extent, a constant distance between the tungsten and work surface, constant angle of attack, as it were, and improved gas coverage of the weld, and again, this consistent angle assists in chasing the wire. When walking the cup while chasing the wire, welding travel speeds are increased significantly. Walking the cup is most-often performed on stainless and carbon steel, in bevel or v-groove pipe applications, or in certain limited filet weld applications. It is almost impossible to walk the cup on aluminum, except in limited filet applications or situations.
Learn to free-hand first. The hand/eye coordination required for free hand proficiency (holding the torch off of the work surface and dipping the filler metal rod into the weld puddle as needed) will make you that much better when you eventually learn to walk the cup.
Just my .02 cents and some of the instructors out there may disagree with me.
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I think the way it was done on the pipe was a smaller cup was used to do the root. Then bigger cups were subsequently used to do the other passes and the cap. When you imagine welding anything from 6 to 20 inch pipe 12 hours a day 6 days a week, then you can understand someone wanting an alternate way to tig. I sure wished I had paid more attention to how it was done while I had a chance, but I had my hands full too
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Originally posted by SignWave View PostFill me in... What the he_ _ is "walking the cup"?
Thanks.
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I think the "walking the cup" should come later. When you first start to tig you have a lot of other things to worry about such as speed, distance of the electrode from the puddle, how to add the filler rod, etc. I think the walking to cup is something the pipe welders invented to make it easier to tig all day long. I worked in a paper mill and I was on the payroll when construction was going on, so I got to see a lot of things I had never seen before. There were hundreds of miles of pipe, and about 90 percent of it had to be tigged, either because it was high pressure steam or things going through the pipe that were very bad. Plus, there was a lot of vibration and thermal cycling. I guess for these reasons the engineers specified tig. The walking the cup does look flashy.
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Which do you think is better...
When someone is learning to tig is it better to learn to walk the cup or the "other way" (I dont know the name of this method) It seems like I see more people doing it the "other way" where they just push the puddle and add filler.Tags: None
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