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Ant428
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    Wed Nov 15, 2017 10:22 am

Holy Smokes! I just tried TIG welding the 6g pipe position on 4" pipe. I failed miserably. This was incredibly hard for me to do. I think I can get the root pass in there....but then walking the cup around that pipe was a fail for me. Anyone else have experience with this? I don't have a problem walking the cup on a flat surface, but on the pipe, it was really hard.
cj737
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That’s why those pipe welders earn big money. Looks easy until you’re upside down welding overhead :D Them boys get my respect!
Poland308
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I use a #4 regular cup until I’m done with the root and hot pass. After that I’ll bump up to a #6 or #7 depending on the day and the sch.
I have more questions than answers

Josh
Ant428
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cj737 wrote:That’s why those pipe welders earn big money. Looks easy until you’re upside down welding overhead :D Them boys get my respect!
What's big money? I'm interested in practicing and taking the 6g test. It may help getting a job in a fab shop too.
Ant428
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I can get the root pass in there just fine now. I am having trouble walking the cup around the pipe with the V groove and filling in.
cj737
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What torch head and cup are you using? My buddy who is a pipeliner taught me to weld pipe and walk the cup, but insisted that a flex head torch and long nosed #8 (also uses the longer gas lens) was the key to making it easy on yourself. The extra length of the cup body helps provide more surface area and angle to the weld line. The flex head definitely makes a difference.

For me, the keys to welding it up properly have been: allowing the root to cool enough that I don't get undercut from accumulated heat, and moving slowly with low enough amps that force me to walk slowly. Scratch TIG too, no pedal. Wire gets laid in the center, then washed outwards. Double dip if you need to and keep a forward, tight arc.

But it still "ain't easy" for mortals...
Ant428
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cj737 wrote:What torch head and cup are you using? My buddy who is a pipeliner taught me to weld pipe and walk the cup, but insisted that a flex head torch and long nosed #8 (also uses the longer gas lens) was the key to making it easy on yourself. The extra length of the cup body helps provide more surface area and angle to the weld line. The flex head definitely makes a difference.

For me, the keys to welding it up properly have been: allowing the root to cool enough that I don't get undercut from accumulated heat, and moving slowly with low enough amps that force me to walk slowly. Scratch TIG too, no pedal. Wire gets laid in the center, then washed outwards. Double dip if you need to and keep a forward, tight arc.

But it still "ain't easy" for mortals...
Thanks for the reply, I am using a 17 style torch with a gas lens. 6 for the root and 8 for fill and cap. I only have a high freq machine so i have to use the foot pedal :( .

Well this is my 3rd try at it. Here are some pictures of the root pass and the fill. I think this is a fail as well :cry: . I still can't seem to get it. I wonder if my bevel is too steep making it hard to wash into the corners. It takes a nice pause on each side to get fusion.
I also think there is too much metal on the inside of the pipe. Any suggestions welcome!

1/4" wall pipe.

Root pass - 3/32 gap, 105 amps 3/32 tungsten 1/8 rod

Fill - 120 amps 1/8 rod
Inside
Inside
20171226_210810.jpg (93.92 KiB) Viewed 1032 times
root pass
root pass
20171226_200212.jpg (90.64 KiB) Viewed 1032 times
fill
fill
20171226_210842.jpg (115.03 KiB) Viewed 1032 times
cj737
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What bevel angle are you using? About 35* is good for that thickness. Bevel to a fine point, no land. Set a 1/16” gap, four tacks. Grab your 3/32 rod and start washing it in. Remember as you travel uphill, the heat is accumulating quickly. Your picture shows a lot of sag on the inside, so I’d suspect too much heat or too wide a gap to start.

After the root, let it cool down to about 250* before you lay the fill pass.
Poland308
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I would bump up the amps a little to about 120. This should help with the lack of fusion on the root, also it will help on your filler pass( it almost looks like your flirting with being cold). That will also help you to travel faster and that will actually reduce the amount of heat input to the piece even though your running hotter. But that won’t change the need for letting it coot between passes.
I have more questions than answers

Josh
Coldman
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What technique are you using for the root pass. Key hole dip? Laywire?


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Ant428
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cj737 wrote:What bevel angle are you using? About 35* is good for that thickness. Bevel to a fine point, no land. Set a 1/16” gap, four tacks. Grab your 3/32 rod and start washing it in. Remember as you travel uphill, the heat is accumulating quickly. Your picture shows a lot of sag on the inside, so I’d suspect too much heat or too wide a gap to start.

After the root, let it cool down to about 250* before you lay the fill pass.
I'm going to try this tomorrow and see how it goes. I will post an update. I'll try the 1/16 gap and 3/32 rod .
Ant428
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Coldman wrote:What technique are you using for the root pass. Key hole dip? Laywire?


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Laywire
Coldman
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With laywire it’s best if gap and wire are the same size. If the wire is bigger as in this case incomplete penetration is high risk. Either widen your gap to 1/8” or use 3/32” wire. 105-110 amps and you’ll do fine. Probably 110-115amps for the second pass.


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Ant428
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Coldman wrote:With laywire it’s best if gap and wire are the same size. If the wire is bigger as in this case incomplete penetration is high risk. Either widen your gap to 1/8” or use 3/32” wire. 105-110 amps and you’ll do fine. Probably 110-115amps for the second pass.


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I will try that again. I did a 3/32 gap once and filled with 3/32 wire at 100 amps and it kept keyholing too much. I'll try moving faster.
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