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Tig welding on tubing and round parts

Posted: Thu Feb 15, 2018 9:04 pm
by ConcealPro
Anyone have some good advice for welding tubing 2" to 4 or 5" and round parts without a positioner? I really struggle getting a good position in tube, and can only go about 1.5 inches at a time without having to reposition.

Re: Tig welding on tubing and round parts

Posted: Fri Feb 16, 2018 12:33 am
by Graveyard
Practice practice practice! It’s been a while since I’ve walked the cup but when I do I like to start at the 6 o clock potion and work up and around. Usually only have to reposition once or not at all depending on if I have room. I’m sure there are others that can give you some better pointers but that’s what I got.

Re: Tig welding on tubing and round parts

Posted: Fri Feb 16, 2018 4:26 am
by weldin mike 27
The absolute thing that people new to welding need to be taught is that, unless you are walking the cup or welding big plate and pipe, you don't very often go too far with out stopping.(Instagram does not help with this at all) On big items, you can prop or rest the cup and a few different tricks, but you do not need to become a welding genius that can weld for a mile. Look at this picture, each of the distinct heat marks is a stop start. That's the beauty of tig, you can make a restart at any point with ease.

Keep up the good work,
Kindest regards, Mick

Re: Tig welding on tubing and round parts

Posted: Fri Feb 16, 2018 5:16 am
by Coldman
Get some pipe stands and quarter them


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Re: Tig welding on tubing and round parts

Posted: Fri Feb 16, 2018 9:01 am
by cj737
weldin mike 27 wrote:The absolute thing that people new to welding need to be taught is that, unless you are walking the cup or welding big plate and pipe, you don't very often go too far with out stopping.
This. It is ALWAYS best to be in good position versus welding farther. Welding out of position will produce poor results unless you are an immortal and professional who has become experienced at it.

Since this is not production welding, take your time and weld it comfortably. If you do weld, stop, re-positon on small tube, I like to rotate the part in "quarters", not just keep advancing the last string. If I rotate the tube/pipe 90* each time I stop, I personally get better results where I can ultimately connect my strings with a couple of beads washing into the "start" of the next piece I'm connecting to. It helps blend all the strings into a more "singular" looking weld.

Re: Tig welding on tubing and round parts

Posted: Fri Feb 16, 2018 7:08 pm
by ConcealPro
Good advice. I get into the habit of trying to stretch it just a little further and end up regreting it.

Re: Tig welding on tubing and round parts

Posted: Fri Feb 16, 2018 9:00 pm
by weldin mike 27
Best of luck

Re: Tig welding on tubing and round parts

Posted: Fri Feb 16, 2018 9:36 pm
by Aaronmnwelder
Hardest thing about anything round is teaching yourself to constantly make adjustments to your torch angle as you go around the the tube or pipe. The smaller the tube the harder cause adjustments have to be made faster. I would get yourself some bigger diameter stuff and practice. Positioning really depends on the part and thickness. If its thick I like laying it horizontal and going for bottom to top. But on thin stuff I prefer flat position up off the table so it's easier to make to adjustments and you can talravel farther. This little 1.25 did aluminum took me awhile to get down.

Re: Tig welding on tubing and round parts

Posted: Sat Feb 24, 2018 7:26 pm
by zank
I always do some dry runs trying to find find how to best hold my wrist/torch to get the best torch angle I can as I move. A light touch on the torch is key and it won't be long before you are rolling the torch in your fingers to keep that torch angle. Lots of practice and a good plan on how you will manipulate the torch will get you to where you want to be.

Re: Tig welding on tubing and round parts

Posted: Sat Feb 24, 2018 9:17 pm
by p4nh4ndle
adding filler to process tubing? that's kinda a nicht-nicht. Even if you eventually want to add filler, I'd start by doing a fusion weld by cup walking. As already stated, as little pressure on the tube as you can manage is the key ti success. Too much and you'll slip, too little and you'll slip, pressure in the wrong direction and you'll slip... the struggle is real.
i had to do quite a bit of this welding at work for the last few weeks. While I do have the luxury of a positioner, not all welds could be rolled out.
When I had to positon weld joints, I found the following pointers to be helpful:
1. Use a gas lens and one that's small enough that you have good control (a 5 or 6 suits me well but ymmv)
2. Use a lot of torch gas flow - 30cfh would not be too high
3. Use a few less amps to give yourself more time to do the walk
4. Overlap your starts & stops by a good 1/4"
5. Get a really good purge before you weld

The extra gas through the torch gives you a little extra cushion to prevent a gray weld bead; the gas lens On .065" wall tubing I found ~35A about right for position welds.

Hope this helps. It took me about half a week of 10h shifts to get really good at these.

Re: Tig welding on tubing and round parts

Posted: Sat Feb 24, 2018 9:47 pm
by oldwelder
I reciently had a job that I had two 1" hydraulic lines that rubbed together from vibration and wore deep grooves in the side of the tube. They were off of a Caterpiller loader hydraulic system. I elected to try to fill the grooves with E-70S2 wire with the TIG system. I am using an old transformer type Miller Gold Star with 3/32 Lathanated tungsten, foot feed with about 150 amp max settings. The grooves were nearly 3/4" wide and not entirely through the tube at any point, it was still working when we found the problem while doing other repairs. I am not sure of the material of the tube, but suspect it might be 4130??
I watched Jody's video on welding 4130 and he suggested using E70S2 rod instead of 4130 to have better luck. I used some stringers and some weave type beads to build up the wall thickness to just above the original, then lightly flapper wheel the tops to blend it back near the original contour. At this point, the job is finished and back on the loader, but I worry about the heat affected zone and if I did more damage than good. Any comments? I guess I will know if it holds when it is back for repairs next time... Thanks. Gary.

Re: Tig welding on tubing and round parts

Posted: Mon Feb 26, 2018 4:21 am
by noddybrian
Done many such repairs in the past but would not consider it these days except to get a machine moveable till a new part is available - sure there are many ways but I always brazed them with oxy acetylene - never had a problem but due to liability issues / insurance any visible damage to hydraulic lines steel or rubber should be replaced as if it's known there was a problem or repair & at a later date it bursts causing an accident you will be responsible.

Re: Tig welding on tubing and round parts

Posted: Mon Feb 26, 2018 8:10 am
by Coldman
While there may not be anything wrong with your repair, you may be liable if there was a problem down the track. If you cut the piece out and welded in a new piece to a wps to which you were qualified, then you can’t really get trouble later.


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Re: Tig welding on tubing and round parts

Posted: Mon Feb 26, 2018 3:55 pm
by Warrenh
I will try to describe this trick and not be too confusing. Instead of holding the torch with the handle pointing towards you, hold the torch at a 90 to your body with palm down. The torch handle would be pointing out to the right for a right handed welder. Put the cup on your workpiece in front of you. This will give you more room to walk the cup.

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Re: Tig welding on tubing and round parts

Posted: Mon Feb 26, 2018 5:09 pm
by cj737
Warrenh wrote:I will try to describe this trick and not be too confusing. Instead of holding the torch with the handle pointing towards you, hold the torch at a 90 to your body with palm down. The torch handle would be pointing out to the right for a right handed welder. Put the cup on your workpiece in front of you. This will give you more room to walk the cup.

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Are you describing “torch perpendicular” to the seam?

Re: Tig welding on tubing and round parts

Posted: Mon Feb 26, 2018 7:15 pm
by Warrenh
The torch would be in line with the weld seam. Your hand would be rotated out to the right with the hand oriented with the palm down. I dont really know what to call this. This would be for horizontal seam. I will try to get a pic at work tomorrow. This isnt earth shattering news. I just dont know how to describe it.

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Re: Tig welding on tubing and round parts

Posted: Mon Feb 26, 2018 11:56 pm
by cj737
Warrenh wrote:The torch would be in line with the weld seam. Your hand would be rotated out to the right with the hand oriented with the palm down. I dont really know what to call this. This would be for horizontal seam. I will try to get a pic at work tomorrow. This isnt earth shattering news. I just dont know how to describe it.

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It’s as I interpreted it. It’s the way I do it, and probably anyone else familiar with the technique. Hand below the cup, walking uphill, torch perpendicular to the pipe/tube, but inline with your weld direction.

Re: Tig welding on tubing and round parts

Posted: Tue Feb 27, 2018 10:55 pm
by Saz
weldin mike 27 wrote:The absolute thing that people new to welding need to be taught is that, unless you are walking the cup or welding big plate and pipe, you don't very often go too far with out stopping.(Instagram does not help with this at all) On big items, you can prop or rest the cup and a few different tricks, but you do not need to become a welding genius that can weld for a mile. Look at this picture, each of the distinct heat marks is a stop start. That's the beauty of tig, you can make a restart at any point with ease.

Keep up the good work,
Kindest regards, Mick
You said it all right there. Instagram makes it seem like EVERYONE knows how to get all the way around a piece of tubing without stopping........ Just go slow, take your time and practice. I'm not very good at it either, but I have gotten way better over the last year or so.