best 6g 5" sch 80 pipe yet!!

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1/8" 70s2 Tig root & Hotpass, 1/8" 7018 Filler/Cap just a few blemishes otherwise I think it looks good. Any suggestions??  Oh and does anyone have like a chain vise arm rest or know how to make one?? That would grip the pipe with like a bicycle chain maybe?? Attached ImagesLast edited by justinT; 03-18-2010 at 02:06 AM.
Reply:What did you do to the weld toelines on the cap?  That doesn't look so good....Benson's Mobile Welding - Dayton, OH metro area - AWS Certified Welding Inspector
Reply:Dab:  it looks to me as though it might could use another pass on top of it.  I dont think he did anything to the toe lines, but it looks as though he did because of underfill maybe?
Reply:Originally Posted by justinT1/8" 70s2 Tig root & Hotpass, 1/8" 7018 Filler/Cap just a few blemishes otherwise I think it looks good. Any suggestions??  Oh and does anyone have like a chain vise arm rest or know how to make one?? That would grip the pipe with like a bicycle chain maybe??
Reply:You need to slow down.  Your bead shape indicates that you're traveling too quickly and at too much of an angle, which accounts for the undercut.
Reply:Thanks for all your replys. I will take everything mentioned into consideration.. I do agree when I get close to finishing a piece i speed up and my welds gets worse + I tend to hold my breath alot. ??
Reply:Pile: yeah we just used a section of angle with a plate tacked on the bottom as a holder for tacking.Justin: regarding the "chain vice grip"; I assume you are looking to use it to rest your forearm on for support (again, school trick) you can find them at most hardware stores in my area or just google "vice grip locking chain clamp". Another trick is to add a couple of small sections of angle to the pads on a C or F clamp and use that as a pipe clamp/armrest.
Reply:thanks :] I did'nt know it had a vice grip on it awesome!!
Reply:it also looks like you have some suckback on your root pass.... to avoid suckback travel faster, add more wire, or turn down your heat some.  On your cap Do Not grind the egde of your weld.  many places wont even let you file or "ring" the egde of your weld to remove the under cut or straigten out your bead.  slow down some and let the undercut fill in.  most important thing when having a good stick weld is to get as comfortable as possible. the more comfortable you are the better you can control your weld. on a scale of 1-10, i give your root a 5 due to too much suck back and your cap a 7 or 8 .
Reply:why 1/8 7018?  you may have better luck with 3/32 7018.  Never used a file on practice pieces before but have on jobs where pipe will be painted and uninsulated.  Are you purging your root pass?  Worked with a bunch of nuclear welders and even on mild steel pipe they would still purge the root and then leave the purge on about 5-7 lbs. the rest of the weld when tig'n.  Even on mild steel take your time when tig'n a root in.  Those same nuclear welders told me if they can they would always let the pipe cool to the touch before tig'n the next few inches.  Not always practical but let it cool as much as possible if you can.  Mild steel can take more heat than stainless pipe but still the same principles.  Don't over heat fill and cap passes either.  good luck.
Reply:Originally Posted by gto_welder01it also looks like you have some suckback on your root pass.... to avoid suckback travel faster, add more wire, or turn down your heat some.  On your cap Do Not grind the egde of your weld.  many places wont even let you file or "ring" the egde of your weld to remove the under cut or straigten out your bead.  slow down some and let the undercut fill in.  most important thing when having a good stick weld is to get as comfortable as possible. the more comfortable you are the better you can control your weld. on a scale of 1-10, i give your root a 5 due to too much suck back and your cap a 7 or 8 .
Reply:Originally Posted by lincweldwhy 1/8 7018?  you may have better luck with 3/32 7018.  Never used a file on practice pieces before but have on jobs where pipe will be painted and uninsulated.  Are you purging your root pass?  Worked with a bunch of nuclear welders and even on mild steel pipe they would still purge the root and then leave the purge on about 5-7 lbs. the rest of the weld when tig'n.  Even on mild steel take your time when tig'n a root in.  Those same nuclear welders told me if they can they would always let the pipe cool to the touch before tig'n the next few inches.  Not always practical but let it cool as much as possible if you can.  Mild steel can take more heat than stainless pipe but still the same principles.  Don't over heat fill and cap passes either.  good luck.
Reply:hey hows it goin? Im new here but not to welding. Lol. You do have quite a bit of suck back/lack of reinforcement. When I tig root pipe I use what I call a knife edge which is a bevel with no land but make sure there is no burr on the i.d. I use a pipeliner half round file to knock off the burr. Space your gap around 1/8 some like it slightly bigger, I use a tight 1/8 gap. Next make sure you are adding enough filler material. Think of it as pushing the filler rod into sand and thats what it should feel like, you want to feel a bit of resistance when adding it. I use a continuous feed method as opposed to dabbing. For your hot pass make sure you are not putting to much heat into the root, this is where you will get the suck back! As far as fill and cap, no reason you cant use 3/32, but I prefer 1/8 because the rate of deposition is faster, I can travel further, and im more steady with 1/8. And for sure SLOW DOWN, find a good speed and look at the bead profile as you go it will tell you speed up or slow down. Shoot for 50% overlap on passes which will in turn fill valleys in between beads. Remember that any high/lows in welding are bad and create stress points. And you should be able to weave a 6g if you want. Its always a good idea to grind the mill scale 2" bak from the joint and for finishing the weld go easy on the grinding. Try using that same half round file to take out the undercut. Any grinding will attract the eye to the fault (undercut) And dont forget that going slow fills undercut. Hope this helps out. Oh and I wouldnt worry about a back purge its not needed.
Reply:Originally Posted by justinT1/8" 70s2 Tig root & Hotpass, 1/8" 7018 Filler/Cap just a few blemishes otherwise I think it looks good. Any suggestions??  Oh and does anyone have like a chain vise arm rest or know how to make one?? That would grip the pipe with like a bicycle chain maybe??