Mig root for 6g on xxx small bore pipe

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Hey everyone, as I read along I'm realizing what a talented bunch of people there is here! Anyways I have a pressure test coming up that requires a mig root on triple x 2" pipe in the 6g position..all new to me! I would like to find out the best way to go about it, the test requires me to do a vertical down root. What type of gap and land should I use? Heat settings I'm not sure of but I know the test is with a miller inverter using .35 wire. What angle should I use on my whip through out the test, would I use a key hole technique or a drag motion? Basically every thing I can find out will help. I do have my filll and cap down packed solid. Thanks guys, I sure need it as my practice run went horribly..aaahhh!
Reply:my hard wire root i like to run a good 1/8th gap and light 3/32 land  i use drag and keep the wire pushing the puddle into root with a nice weave back and forth only so the puddle touches the side. i think it was 18-19 volts maybe 180wire but for some reason that doesnt sound right in my head  you will have to play with itHigh Octane Welding
Reply:X2 on what abec said.  Match the wire feed speed to the land you're going to use.  Might take some practice to work this out for yourself.  Less land and slightly lower wire feed speed might be easier on 2" pipe.  That's small diameter to weld with wire.  Watch your stickout.  Stay tight to the puddle and consistent all the way around.A wider gap is better than a narrow gap; all other things being equal.  Penetration is not a strong suit for short circuit MIG.Benson's Mobile Welding - Dayton, OH metro area - AWS Certified Welding Inspector
Reply:Originally Posted by A_DAB_will_doX2 on what abec said.  Match the wire feed speed to the land you're going to use.  Might take some practice to work this out for yourself.  Less land and slightly lower wire feed speed might be easier on 2" pipe.  That's small diameter to weld with wire.  Watch your stickout.  Stay tight to the puddle and consistent all the way around.A wider gap is better than a narrow gap; all other things being equal.  Penetration is not a strong suit for short circuit MIG.
Reply:Just one more thing here, what about fit up as to placement of tacks I was using 2 bridge tacks, one at about 11:30 and the other at about 8:00 and found it wasn't sufficient to keep the gap from closing quickly but it was a lot easier in regards to not having to stop. I was thinking of using one stitch on the top 3/4 long and one on the bottom at 3/4 followed by a light bridge tack on one side about 9:00 so I could grind out easy when starting the second half of the root.
Reply:whats the test allowing for tacks ?High Octane Welding
Reply:Originally Posted by abecwhats the test allowing for tacks ?
Reply:Here's two vids that might have a tip or two for you.FWIW,~JohnJust a couple welders, big hammers, grinders, and torches.Work will free you.Men in dirty jeans built this country, while men in clean suits have destroyed it. Trump/Carson 2016-2024
Reply:I haven't done much 6G MIG root but have done a bunch of roll welded MIG root. For 2" you probably want around 17 or 18 volts and about 110 amps. You want a good 1/8" gap. A 5/32" gap rod is good to use because the gap closes half the width by the end. Generally no land in production but a slight land for a test, like 1/16. Usually with MIG roots you use bridge tacks and on 2" 3 good tacks is usually sufficient. Start your weld just in front of the tack. On the top gravity helps so you don't need to push the wire much to get proper penetration. Coming down the side you just slowly rotate your wrist side to side keeping the arc on the bevel just a little above the bottom edge. It's OK to rest the tapered nozzle on the pipe as you slowly weave. You can usually tell when your just melting the edge. The slight land gives you a little more meat to work with. On the bottom you have to push the wire/arc closer to the edge(sometimes almost right through the gap) to get proper penetration. Be aware of where your tacks are so you don't hit the tack with the nozzle. When you come to a tack, you grind it out and feather your stop. Make sure to feather your start as well when you're ready to the final section. Overlap enough to get a good puddle established at your tie in. It will be ground out for the hot pass so doesn't matter if it starts cold. Try and practice a few first. MIG roots are generally easier to do than stick but sometimes they can fail for no apparent reason. BTDT on a job test but got a second chance. Did another one with pretty much the same technique and it was flawless. The foreman said my first one looked perfect and he had no idea why it failed the bend test. I think that's why he let me try again. Good luck!