a few questions for you tig welders

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hey guys i've been burning tig for a little while maybe 300 hours i can lay a nice root bead in a 4", or 2" pipe i notice on the 6g it's hard if your right handed to lay a good hot pass on the right side of the pipe, because it's easy to undercut because it's hard to see and hard to work against the tendancy to use the incorrect torch angles there.what i've been wanting to know from the more expirienced are the basic differences between welding stainless and carbon. i notice it does'nt flow as easily and i have to travel slower if i turn up the heat the puddle gets hard to control and the base metal holds the heat more so the penetration gets deeper as the weld progresses. also know to use a smaller gap because it tends to distort more so a 1/8 gap and 3/32 wire. you prosout there got any input on welding stainless pipe with a tig torch?
Reply:I don't really have any experience myself, but I did find this website online with some videos that may help you. I notice there are a couple on stainless steelhttp://www.tonywelding.com/I actually interviewed this guy for the JoeWelder.com site. He's got a lot of experience training at a vo-tech school in California.  http://joewelder.com/2008/08/05/who-is-tony-welding/Also, here's an article from Tube and Pipe Journal about welding titanium tubing. I believe many of the tips will serve you well in welding stainless also (importance of cleanliness and good gas coverage)http://www.thefabricator.com/ArcWeld...le.cfm?ID=2037Hope that helps!-----------------------Carmen Electrodewww.CarmenElectrode.comand the boss blogs at  www.JoeWelder.comall powered by  www.Arc-Zone.com
Reply:You DON'T turn the heat up for stainless.  If anything you turn it down because it doesn't transfer the heat.  Stainless just has a sluggish puddle that you have to get used to.  You think that's bad, try welding Inconels.And if you're going to be a pipe welder, get used to welding with the torch in your left hand!  If you have to use your right hand, be ready and willing to manipulate your body in every way possible.  Start akward, and finish comfortable, not the other way around.
Reply:The other thing with stainless is people try to use the sluggish puddle as an excuse too go slow.While it is easier in some ways to go slow, the material heat soaks more and more and so ultimately you run into the situation you described, where you just can't control the puddle because of all of the heat. The puddle wanders all over.Also the material then cools more slowly, which is bad for carbide precipiation and makes keeping enough shielding gas on everything difficult as well. Use as much heat as speed as you can while still keeping your dips accurate.
Reply:thanks for all the feedback on this, that tip about working with the left hand is good advice i see welding on a 6g it's a real pain welding up the right side, that makes a lot of sense right there.i guess the trick is to first go cool and slow and, as it takes up the heat to travel a little faster and faster and allow it to cool when it gets to the point where your getting excess penetration and melt through. another thing is it tends to distort so smaller gaps and smaller wire alow for less heat input which helps with the whole coefficient of expansion thing.i think i'll practice with my left hand, haven't done that since i injured my right and really had to get one off (just kidding)one of my instructors showed me a workaround for that he just welds from 5:00 down to 6:00 it's cheating but he gets away with it and this allows him a little more comfort on the right side but working left handed would be advantageous for sure.i know purges are mandatory on stainless.Last edited by ian_s; 11-01-2008 at 07:49 PM.
Reply:I do the same as your instructor but then jump over to left handed for the rest (lazy aRse me )What grade of stainless is it and what schd?    316 over 2"  needs a gap but under that and with the lesser grades feather edge it and butt it up tight.  When you light up wait there, plenty of angle on the torch, when you see the pool 'pop' in and then see the little black spinning dot in the pool it's time to start moving.   316 over 2" run some gap with about the same technique. The heats are down a little compared to carbon, but with time that will change to once you get your hand into it.I'd rather be hunting........USE ENOUGH HEAT.......Drifting around Aussie welding more pipe up, for something different.....wanting to get home.
Reply:just 309 schedule 80 2", so your'e saying don't use any filler just butt it up and weld together huh?ever use backup rings?i heard those are cool take a lot of guesswork out of the money bead (root pass)Last edited by ian_s; 11-01-2008 at 10:06 PM.
Reply:Only for the root run, never used backup rings, the man pays me a lot to not have to use them If you struggle with feather and no gap then feather and put a very small gap in (2mm) and use a 1.6mm filler but with the same technique.I'd rather be hunting........USE ENOUGH HEAT.......Drifting around Aussie welding more pipe up, for something different.....wanting to get home.
Reply:tony's welding is very comprehensive, it's easier to butt it up and weld it that way sometimes not permissible though.
Reply:"Start akward, and finish comfortable, not the other way around."I like that. I always find myself, not only with tig, but also stick welding, that i start comfortable, but then as the bead grows longer, and my arm position changes, i get sh1tty results like arc blow and long arc (porosity)
Reply:Originally Posted by Supe  Start akward, and finish comfortable, not the other way around.
Reply:Most definatly start using your left hand, becoming proficient in using both hands while welding is essential to be a good pipe welder as many here will agree with. This is just my personal experience, but while doing my stainless (2" sch 160) weather it be stick root or tig root, i found that the use of small electrode, filler wire in combonation with smaller gap allows for less distortion, as a rule "less heat, less distortion" For my stick root i use a 5/64th electrode, for my tig roots, i use a 1/16th filler wire, w/ 3/32 gap. Also with stainless you have to watch your heat input, you can "burn" stainless if you will, if you get the stainless coupon to hot by going too slow, you risk whats called carbide precipitation, thus losing the properties of corrosion resistance that stainless holds. And as stated above, try welding different types of inconel,  or monel, or hastaloy. Thats where she gets fun!