tig root 2G lay wire technique?

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07-03-2016, 12:26 AM
GaveUpOnTV

tig root 2G lay wire technique?

I have the hardest time with the lay wire technique. The 1/8" er70s-6 wire 'beads' up and I have huge gaps. Once in a while I will get a decent root, but a lot of times even then, there will be a gap at the top. I have a 210ext (but I do the same at school, where they have traditional transformer machines). I'm using 80 amps, and I seem to get better results than 90 or 95 amps. I'm using a 3/32 gap and no land and I can't tell any difference when I use a 1/8 inch gap. I'm welding 5" pipe, both sch 40 and sch 80.
What I think I'm doing wrong, is I'm not bending the wire exactly at the point it is melting and bending easiest. I think it's beading up because the wire isn't touching the metal, which is a heat sink.
I'm getting so frustrated, I have been doing the keyhole method, gap it at 3/32 and making a keyhole, filling it up, making a keyhole, dabbing and filling it up, etc. I seem to be getting good root beads this way, pretty decent IMO.

Thanks for any advice!
07-03-2016, 02:21 AM
zoama

You still have to push the filler at times to satisfy the puddle.
07-03-2016, 05:20 AM
GaveUpOnTV

Quote:

Originally Posted by zoama

You still have to push the filler at times to satisfy the puddle.

Ah, that may be it. I feel it 'notch' every once in a while, but I'm concentrating on the torch mostly. I wish I had more material to practice on. Also I don't really get to see what's behind the torch, but I always feel the rod 'collapse'. At other times I think that I have got a good root pass only to lower my torch hand and see a mess.
07-03-2016, 09:38 PM
everlastsupport

If what you are filling is bigger than the filler rod you will have to feed it in as well.
07-03-2016, 10:42 PM
GaveUpOnTV

Quote:

Originally Posted by everlastsupport

If what you are filling is bigger than the filler rod you will have to feed it in as well.

I use the 1/8" rod to space the joints of the pipe. When I tack the pipe together, it closes up and it's very difficult to get the rod back out (I file one side of the rod so I twist it to remove). I am left with a groove that's just slightly less that the rod size I've used to space it. When I try to do the root pass, (after grinding the tacks so that the wire will have a more gradual bend when it goes over the tack) I press the rod as close as I can against the groove and I use about 80 amps to melt the wire in. I am having better 'luck' using 80 amps than 90 or so, it melts it too fast to bend it and I'll often just have a loose rod in my hand because it's melted and liquid and no longer attached to the groove. I think that I'm not getting the arc at the place it is bending or something, otherwise the rod wouldn't melt so fast, heat would be sucked from the rod because of it's touching the metal.
I'm paying too much attention to the torch hand and I'm not watching where the rod is flexible so that sometimes the rod is not touching the metal when I have the arc on it, and of course it just melts, the heat cannot go anywhere.
I think I'm a little slower picking this up, but I just need lots of practice. I got a lathe that I am getting going so that I can take the pieces of pipe that I've welded together and cut them up and bevel them so I can weld them again. I'll try that tonight maybe (cutting and beveling the pipe)
My teacher advised me to use a 3/32" root opening, with a 3/32 land, I haven't tried that yet. I didn't think to ask him if I should also use 3/32" rod to do the root pass and use the 1/8" rod. Or maybe that was stick? Does anybody know offhand what most people use? I will have to double check that I have everything ok. I'm welding both sch 40 and sch 80, the root pass specs should be the same in both cases, shouldn't they?
07-04-2016, 12:45 AM
Rambozo

Also make sure your torch angle is pretty much always pointed towards the center of the pipe. You want to direct the arc towards the pipe, not the filler. Then position your head so you can see the puddle without having to change the torch angle. There are a lot of pipe techniques, different people do better with some than others.
08-08-2016, 05:17 AM
GaveUpOnTV

I've gotten much better getting the rod bent around the pipe. I ended up using 140 amps, it worked better than 80 amps. The advice about keeping pressure on the end of the filler rod that pretty much did the trick.
I've had the filler wire fall out for the longest time, but it wasn't because it wasn't tight against the groove, it's because it's not fused in to the metal, slightly. I've improved there by making sure that both ends of the rod is attached to the tack weld, that gets rid of most of my 'fall outs'. Hopefully more practice will help me to someday get that rod slightly fused to the groove. Actually it's happened a couple of times, but mostly by accident.
Does anybody have any advice on getting that slight amount of fusion there?
Like I said, the advice to keep the pressure on the end of the rod so that I can keep the wire in one piece really helped.
BTW, to get my PowerArc 300 into the TIG world, is all I need a torch with a manual shut off? I'm running pretty close to the duty cycle with the 210EXT. I'm running 130-140 amps for quite a while.
08-08-2016, 02:30 PM
Rambozo

Quote:

Originally Posted by GaveUpOnTV

I've gotten much better getting the rod bent around the pipe. I ended up using 140 amps, it worked better than 80 amps. The advice about keeping pressure on the end of the filler rod that pretty much did the trick.
I've had the filler wire fall out for the longest time, but it wasn't because it wasn't tight against the groove, it's because it's not fused in to the metal, slightly. I've improved there by making sure that both ends of the rod is attached to the tack weld, that gets rid of most of my 'fall outs'. Hopefully more practice will help me to someday get that rod slightly fused to the groove. Actually it's happened a couple of times, but mostly by accident.
Does anybody have any advice on getting that slight amount of fusion there?
Like I said, the advice to keep the pressure on the end of the rod so that I can keep the wire in one piece really helped.
BTW, to get my PowerArc 300 into the TIG world, is all I need a torch with a manual shut off? I'm running pretty close to the duty cycle with the 210EXT. I'm running 130-140 amps for quite a while.

140 amps is much more like it. It still sounds like you might not be getting good fusion and more just melting the filler rod. You need to completely consume the rod in the puddle, not just slightly fuse it to the pipe. The trick is to put the heat into the pipe so the puddle is kept hot enough to melt the filler rod. Don't melt the rod with the arc. How much reinforcement are you getting inside the pipe? The puddle should flow into the inside of the pipe and give you a slight crown. Your WPS should have the required/allowed limits. Usually around 1/32" to 1/16"

130-140 on your 210EXT should be no problem. That is right around the 100% duty cycle for that machine. To use your 300 all you need is a torch. One with a valve would be the best, but isn't required.