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Tig on 6" carbon pipe sch 80

Posted: Thu Feb 12, 2015 12:59 am
by theglassshroom
Ok, guys. I am in a bind, and I need to get really freaking good at welding pipe in a hurry, so I'm hoping all of you can give me an epiphany as to what is going wrong here. I have had a terrible time troubleshooting my pipe welding, and I have yet to encounter anyone that gives me anything but vague information or the stereotypical, "Just practice." Practice makes permanent, perfect practice makes perfect.

My first issue seems to be my tacking, because no matter how flush I get that f*cker, as soon as I get my tacks in, it is off by an annoyingly minor amount.

My second issue is my root. I am not getting that nice flush, or wedding band appearance. I am getting suck back that is about 2mm or so. I am running about 90amps, using 8th inch er70s2 with an 8th inch gap, 30CHF Ar., and my stick-out is about 8th inch. I am running into three problems: Either I am somehow washing up too far, or I can't get it to tie in, or my wire starts running away from me.

Thirdly, is that when I am working the underside of the pipe, I am hitting blind spots, and one cannot easily weld what they can't see. To add a rock to this hard place, if I bring my tungsten out further to compensate, the compensatory angle required has a tendency to throw heat onto my filler, and or, I end up sticking and contaminating.

Finally, I have the issue of my cap. I am trying to put down 2 or 3 beads, and I either end up getting undercut, or I seem to lose frame of reference, and end up rolling out too far on my first bead, and subsequently end up with an off kilter cap.

Please give me nauseatingly-explicit detail to work with. I am one of these people that prefers to mentally draw logical conclusions, then transfer them to almost a pseudo-muscle memory, so the more descriptive you can be, the better off I will be.

Thank you all for your time.

Re: Tig on 6" carbon pipe sch 80

Posted: Thu Feb 12, 2015 1:12 am
by newschoppafowah
What kind of machine are you using?

Regular collet setup or a lens?

The big thing, which I can see from your mention of blindness and undercut, what kind of angle? Why are you in a blind position? What DS are you going for? How much of a hurry?

Information is the only way any of the pipe guys around here can help. And they'll need a ton of it if you're in the miracle business. ;)

Re: Tig on 6" carbon pipe sch 80

Posted: Thu Feb 12, 2015 2:21 am
by taz
Ditch that 1/8 wire and get yourself some 3/32 filler.
Oh and practice, practice, practice ;)

Re: Tig on 6" carbon pipe sch 80

Posted: Thu Feb 12, 2015 2:22 am
by theglassshroom
I'm running off of an old Miller Shop Master, I'm using a regular collet setup, I'm using 1/8th" 2% Thoriated tungsten. Blind spots are occurring when on the bottom half of the pipe, usually between 7 and 9 o'clock, and 5 and 3 o'clock, respectively, when I'm still on the floor. I'm holding my torch like one regularly would, and as I'm going, I'm having a hard time visualizing my puddle, either from head on, or the side.

Re: Tig on 6" carbon pipe sch 80

Posted: Thu Feb 12, 2015 2:23 am
by theglassshroom
taz wrote:Ditch that 1/8 wire and get yourself some 3/32 filler.
Oh and practice, practice, practice ;)
3/32" with a 1/8" gap?

Re: Tig on 6" carbon pipe sch 80

Posted: Thu Feb 12, 2015 2:26 am
by taz
Yes. Why do you find it strange?

Re: Tig on 6" carbon pipe sch 80

Posted: Thu Feb 12, 2015 2:29 am
by taz
Also try not to start at 6 o'clock. Start at around 5 o'clock and work through 6 to seven o'clock. That way you can avoid tie ins at the bottom of the pipe that can be below flush

Re: Tig on 6" carbon pipe sch 80

Posted: Thu Feb 12, 2015 12:08 pm
by theglassshroom
I have never used 3/32 with a 1/8" gap, and I can't find jack shit for tutorials on that. How, exactly, is that supposed to deal with my suck back issues?

Re: Tig on 6" carbon pipe sch 80

Posted: Thu Feb 12, 2015 12:53 pm
by Rick_H
The 1/8" gap will tweek in even with 4 good tacks, I also prefer a 3/32" filler for my root with 1/8" -3/32" gap. Are you walking the cup or dabbing/key hole? Do you feather your tacks? Are you using both hands or only your dominate hand?

If you can't see the puddle your guessing, you have to find where you are comfortable. You say 6 o'clock are you doing 5g? That is about the hardest position with pipe.

Practice makes perfect, only way you'll get better at pipe. Make sure you are cleaning up the bevels to shiny metal, feather tacks of needed, brush heavily in between passes, let it cool in between passes. Take your time and concentrate on placing the bead where you need it to be when stacking.....very important.

Re: Tig on 6" carbon pipe sch 80

Posted: Thu Feb 12, 2015 6:38 pm
by Coldman
Hi glassshroom. I got two cents worth of tips for you. Firstly, coming from my part of the world, we only use 3/32" wire so everything I do is based on that and I can't comment on 1/8" wire because I've never even seen it.

OK. Tip 1. Loose the ER70S-2 wire. Use S-4 or S-6. If you want to know why here is a link to a comparison I did a while back.
http://forum.weldingtipsandtricks.com/v ... comparison

Tip2. If you can get good fitups, use Jody's laywire method.
Here are some pics of a 6" sched 40 coupon I had to do a while back.
root.jpg
root.jpg (73.32 KiB) Viewed 2022 times
cap.jpg
cap.jpg (61.2 KiB) Viewed 2022 times
Prep & weld specs:
3/32" gap
30* bevel, no land
Argon 11L/min
No.6 cup and stubbie gas lense on a 26 torch
3/32" Lanthanated tungsten, 2%, 20* point, keep a tight arc.
ER70S-4 wire, 3/32"
Position 6G
Passes 4
Root pass 105amps
Hot pass 110amps
Fill Pass 125amps
Cap 140amps

I avoid stringers purely to do the fastest weld possible, but just about all my work is on sched 40. I do keep my prep angle to 30* to keep the cap width to a minimum.

If you practice this method, you can get good results as quick as you can develop muscle memory.

Starting at 5 o'clock is good advice. I put a decent tack at 6 o'clock, it does the same thing.

Good luck!

Re: Tig on 6" carbon pipe sch 80

Posted: Thu Feb 12, 2015 8:43 pm
by Braehill
@Coldman,
I've seen your comparison with the different Silicon content and have to agree with them. For most of my home projects I use S6 and prefer it. That being said, when I'm welding at work all the WPS's for Carbon pipe call for S2 and I have to use it, not a single stick of S4 or S6 is on site. Here in the US it's the standard and he may as well learn to weld with it.

I hate welding with 6010, but if I have to stick weld pipe and it's called out in the WPS I have to use it like it or not. I guess if you learn to weld with the hard stuff, the others should seem easier.

@glasshroom,
I know it's not what you want to hear, but I don't think there's anybody here that doesn't want to be able to weld great with all materials, in all positions. I also know that the ones who can didn't learn how to from a couple paragraphs of instruction from this site or any other for that matter. The advise that you're given about practice is the best advise available, learning to weld is about watching and noting what works and what doesn't. Change one varible at a time and see what effect it has on your weld, move to the next, rinse, lather, repeat. I know that I'm going to be very pissed off if someone can learn what took me years to learn from reading a handful of responses on the internet. It all comes with hood time.

Len

Re: Tig on 6" carbon pipe sch 80

Posted: Thu Feb 12, 2015 9:49 pm
by Otto Nobedder
theglassshroom wrote:I have never used 3/32 with a 1/8" gap, and I can't find jack shit for tutorials on that. How, exactly, is that supposed to deal with my suck back issues?
Suck-back does not happen on the root pass. If this is where you're seeing lack of penetration/root reinforcement, it's from either too much heat or not enough filler (or too slow a travel, or too fast a travel... However you want to view it).

Suck-back is when your fill pass gets the root too hot, and draws it toward the outside (hence the name... The root material gets sucked back toward the surface.

You can weld a 1/8" gap with 3/32 wire, and you can weld a 3/32 gap with 1/8" wire. You must understand what is happening at the puddle, and only hood-time will teach that. Here, you will find suggestions, not solutions. Take them for what they're worth, try them under the hood, and report your results. This will refine the suggestions.

Steve S

Re: Tig on 6" carbon pipe sch 80

Posted: Thu Feb 12, 2015 11:06 pm
by Coldman
@Braehill
I agree with everything you say. I was just giving my 2cents worth to the OP who stated he wanted to get good fast - something must be sacrificed.
Incidently, I learned on s-2 at tafe college. Our teachers told us (in cert class) we should be using s-4 or 6 but they were permitted to order and supply one kind of wire only and apparently the boilermaker apprentices kicked up a stink about going away from s-2 so they backed off. S-2 wire is also very common here in Oz but (from what I have been told by inspectors and gun pipe welders) never specified or used in major projects like gas pipelines, petrochem, platforms etc. Always s-4 or 6. Most of these guys tell me s-2 is cheap crap which is wrong, because around here its costs more than the other wires. I still have some 1/16" s-2 which I am using up on 1/2" capping passes but there is no way I would use s-2 for a root pass if I had a choice. It makes no sense.

I do know of one exception. A gas plant up in Gladstone where s-2 was specified because apparently s-2 was better at low temperatures (sounds like bs to me because they weren't using A333 pipe). Many of the welders climbed down out of their trees and expressed their displeasure, in a colloquial manner, but could not get it changed. :roll:

Re: Tig on 6" carbon pipe sch 80

Posted: Fri Feb 13, 2015 12:08 am
by weldin mike 27
What you will also find about the gas plant is that Bechtel will not supply /support anything but American consumables. They ran out of Lincoln Excalibur 7018s and would not even look at WIA ones which are probably way better quality.

Re: Tig on 6" carbon pipe sch 80

Posted: Fri Feb 13, 2015 12:39 am
by Braehill
It looks like the OP is also in school and probably doesn't get to choose what filler wire to use, and likely for the same reason you mentioned.

Last time I questioned what filler wire we were using the engineer told me that until my signature was the one at the bottom of the drawing I should stick to what I do best. We will be replacing that piping in April because of a weld joint failure that we had in July, not 6 monthes after it was installed. It replaced a pipe that was installed in 1966. That engineer got replaced in July. My agreement or disagreement with some things usually don't outweigh their academic pedigree, seems there's no degree from the school of hard knocks.

Len

Re: Tig on 6" carbon pipe sch 80

Posted: Fri Feb 13, 2015 1:26 am
by Coldman
@Mike
seems to me there was some talk of coors & crawdad... :lol: :lol: :lol:

@Len. Amen to that.
Look on the bright side. That sob is keeping you in a job. :D

Re: Tig on 6" carbon pipe sch 80

Posted: Fri Feb 13, 2015 2:03 am
by weldin mike 27
And good ol boys.

Re: Tig on 6" carbon pipe sch 80

Posted: Fri Feb 13, 2015 2:13 am
by Coldman
You tried that coors?

Re: Tig on 6" carbon pipe sch 80

Posted: Fri Feb 13, 2015 2:18 am
by weldin mike 27
Nope. Had a Miller genuine draft once. Miller chills too. But nothing else. Except Jack Daniels

Re: Tig on 6" carbon pipe sch 80

Posted: Fri Feb 13, 2015 2:23 am
by Coldman
I was over there one time. Watching tv the ad for coors came on and they were saying they made it with the purest melt water from the rocky mountains high peaks and the best hops etc. Oh boy that sounds great so I went down the local bottlo and got some for the fridge. Waiting for it to get cold I was drooling with expectation. When it was cold I tried it and proceeded to spray it on the wall. :shock:

Re: Tig on 6" carbon pipe sch 80

Posted: Fri Feb 13, 2015 2:46 am
by weldin mike 27
Like sex in a canoe?

Re: Tig on 6" carbon pipe sch 80

Posted: Fri Feb 13, 2015 2:48 am
by Coldman
Oh yer. It was almost a combination mouth and nose to ground.

Re: Tig on 6" carbon pipe sch 80

Posted: Fri Feb 13, 2015 2:52 am
by Coldman
Spray transfer.

Re: Tig on 6" carbon pipe sch 80

Posted: Sat Feb 14, 2015 12:58 am
by newschoppafowah
God, you drank coors?

I'm sorry you had to experience that. :lol:

Re: Tig on 6" carbon pipe sch 80

Posted: Sat Feb 14, 2015 2:30 pm
by TRACKRANGER
Getting back on track, you mention 1/8th inch gap. Is the pipe joint beveled? If so, what angle?