Tig pipe student

admin

I have about 80 hours tig pipe experience (actually much less if you dont include grinding and breaks) on 2" sch 80 and 40 mild steel on 5g and 2g. I make the bevel with a grinder and use a die grinder to clean off the rust on the inside of the pipe 1/2 " on both sides of the root. I find that on the 5g the overhead and overhead/vertical area is the toughest to get solid root penetration. So what I've done is just sorta skipped that and have done 2g rolling since I do find that it's quite a bit easier and will give me a general idea of what I have to do to get that 100% penetration for the harder 6g and 5g. I'm having trouble getting the root through more on the sch 80 then the 40. Hell.... i bet sch 10 would be pretty easy... but unfortunately my rented school doesnt have it. I've watched a few videos on youtube and they do the same things ive tryed... aka  keyhole, dip, or lay the wire and just weld over it like in welding tips and tricks and they arent working very well for some reason... even though i know I'm doing the same thing I see in those vids. I plan on being 2g, 6g, and 5g certified in a month because i know ALL i have to do is get that damn root through ALL the way around because to get certified all I have to do is grind flush the root and face and mail the coupons to the certifier who does a bend test on em. The outside/face is easy... i just need to get that root all the way through... doesnt have to look pretty at all.. as again, ill just grind it flush for the coupons anyways. I know there has to be an "easy" way to go about this..... Btw, 1/8 gap, 3/32 filler, 75 amps, 50 cu on the argon, #5 cup, 3/32 red tungsten, 2" pipe mild steel(old and rusty). I will post up detailed pics on monday. Tips and further questions are much appreciated!! TY(Another question I have is... is it ok to breath in the pipe fumes.. cause when I weld I try and get as close as possible to the puddle and I smell that skunky smell... surely that cant be good for my lungs!??)Last edited by rosrock; 09-07-2013 at 01:30 AM.
Reply:Originally Posted by rosrockThe outside/face is easy... i just need to get that root all the way through... doesnt have to look pretty at all.. as again, ill just grind it flush for the coupons anyways. I know there has to be an "easy" way to go about this..... Btw, 1/8 gap, 3/32 filler, 75 amps, 50 cu on the argon, #5 cup, 3/32 red tungsten, 2" pipe mild steel(old and rusty). I will post up detailed pics on monday. Tips and further questions are much appreciated!! TY(Another question I have is... is it ok to breath in the pipe fumes.. cause when I weld I try and get as close as possible to the puddle and I smell that skunky smell... surely that cant be good for my lungs!??)
Reply:Probably the most reliable way of getting overhead penetration.  A tight 1/8th gap, 90-95 amps, 1/8" filler.  Basically a lay technique, starting at 6 o'clock, make your bridge, feed wire gently while altering your arc no wider than the width of your gap.  You want to pace yourself so a convex bead develops on the exterior.  As you advance to 7 and 8 o'clock you widen your arc movement so that by the time you reach 9 o'clock, your exterior bead profile is flat.First pic shows cut-a-way at 6 o'clock.Second pic shows bead profile at 6 o'clock at the soapstone mark and 9 o'clock at top.  Knock the high points off with a grinder and you're ready for hot pass.Last edited by OldSparks; 09-07-2013 at 03:19 PM.
Reply:Forget the 1/8" gap and 1/8" filler.I like smaller filler as it consumes better in the puddle. Turn the heat up to around 100 amps and get some 1/16" filler and keep feeding it in there. If your keyhole starts getting away from you cram the wire on the sides not in the middle. I x-ray tig every day. Btw I'm not afraid of the 1/8" gap just forget the big filler wire.Also Imo the lay wire technique sucks and can simply be a guessing game.
Reply:A lot of the inspections you'll encounter on the job are visual. If your weld doesn't pass visual you're not going to be employed for long. I would get out of the habit of thinking "it doesn't matter what it looks like..." or "all I need to do is get the root in", because it does matter. It doesn't need to be perfect but it needs to look like you know what you're doing. Other than that, I'd use the above ^ tips. Although I normally run my root on around 85. If you're getting suck back you can always bump it up 5 or so amps. The edges of the filler wire should sit on the knife edges of the bevel, and go no farther than the width of the wire/gap. This will ensure you're actually pushing through the edges and not just washing the metal up onto the walls.  Also, when you run your hot pass, you can put pressure on the root via the filler wire and that will help push it through some as well. The only other thing I can say is, make sure you're getting underneath the pipe and looking up at the weld.The attached image is the root pass from the inside of a 5G on 5" mild steel. Ran on 85 amps.I like lay wire because it's easy, and I can do it well every time. I've done drip root with stainless... up to a 5/32 gap with 3/32 filler and I can get it done but it takes me twice as long. Attached ImagesLast edited by akabadnews; 09-07-2013 at 04:06 PM.
Reply:Everyone develops a way to weld, you need to try different things to find what works best for you. I like 3/32" 70S2 and around 95-105 amps, I usually laywire but I don't just wash over the wire, I push lots of it into the joint as I move. Its like dipping but without pulling the filler away at all and keeping a constant feed rate.Airco Ac/Dc 300 HeliwelderMillerMatic 200 (stolen)Miller Maxstar 150STLMiller AEAD200LE (welding and generating power) Hobart MIG