Need help Welding Pinhole on High pressure steam line.

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May be the wrong place to be asking this. but top welding forum on GoogleI work on steam lines with an average 140 PSI. On a 8 inch, 80 grade, 300PSI Max, carbon steel pipe. I installed a welded-in gate valve. I also installed a bypass, which where 2 holes on the pipe on each side of the valve and welded a weldolet on the holes. My welds for the gate valve to the pipe were x ray tested and passed as solid. my weldolet welds were not tested, i told the inspector not to worry about them. (BAD MOVE). both my welds on the valve and weldolets were a single pass with 1/8 6010 5P rod. the hot pass and cap for both were 3/32 7018. few weeks later they fully charge the line, about 3-5 days later my weldolet begins to leak. it sounds like a leaf blower walking up to it from 100 ft yet a 3/32 rod wont fit in the pinhole. Anyways today i begin to weld over the pinhole to try and stop the leak. after chasing the pinhole for about an hour i manage to get it down to a quiet hiss. by now i have this 2 inch ball of metal under my weldolet, which i plan to fix when that line gets shut down in February. For now i need to take care of the leak which will most likely get bigger. i came here to ask if anyone had any suggestions. after some thinking today i may hammer in some wood, maybe it'll hold the pressure back enough to run a bead over it? Obviously an outage is not possible until February.
Reply:I can't help because I haven't done anything like that, curious about the answer to the problem though. Maybe start the bead 1/4-3/8" away from the pin hole and wash the 6010 into it to seal then run a 7018 over that? Did you grind around the hole any?Airco Ac/Dc 300 HeliwelderMillerMatic 200 (stolen)Miller Maxstar 150STLMiller AEAD200LE (welding and generating power) Hobart MIG
Reply:i wired wheeled the hole, got it nice and clean. yes i did exactly that, started about an 8th of an inch away welding above it going downhill , tried going uphill, left to right, right to left. i was there for an hour. i actually got it to stop for about 5 seconds then i could hear it cracking then it begins to hiss. i turned the heat down to dig less metal but that damn hiss always comes back. when welding over the pin hole, in the puddle is a needle size hole the moves around with the puddle. i plan to either jam wood in the hole, or try to stop the leak completely again for that short time and spray a jet stream of ice water on it to harden it and keep running a bead, cooling it, another bead, cool it. until i can run 7018 over it. i'm motivated to fix it because i was able to bring it down from the sound of a leaf blower to a quiet hiss.
Reply:Could you hammer a nail into it then weld over it? I don't think wood would hold but I don't know. Or maybe heat it with a torch then hammer a nail into it, when it cools it may be sealed good enough.Airco Ac/Dc 300 HeliwelderMillerMatic 200 (stolen)Miller Maxstar 150STLMiller AEAD200LE (welding and generating power) Hobart MIG
Reply:check your PM
Reply:You may have something there with heating a nail and hit it in, thanks. but yea i didn't use a nail instead i used a rod, i actually sharpened it into a point on and when i hit in it actually worked a little, then i welded it and the rod i guess melted. i'll try a nail next time.
Reply:is there a soft metal i can sharpen into a nail? maybe brass? i'm thinking the pinhole may not be a perfect circle. if i hit the nail in, it either may make the hole bigger because nails are strong or not completely cover the hole and it leaks by, leaks less but still leaks. i say a soft metal i can hammer in, that will take form of the hole and hold off pressure, which is the idea behind jamming wood, it'll take shape of the hole. and i assume the steams condensate would seep into the wood and expand the wood
Reply:Center punch around the hole to push the metal into the hole and close it up. Then you may be able to weld over it, since it wont be an active leak.
Reply:well then i was being very hard headed because my co worker kept trying to do that, he tried about 4 times after each weld but he only made the hole worse. at one point it worked and quickly welded over it but the hiss came back. kept telling him to stop, shouldve been more patient and kept trying that.
Reply:It doesn't always work, some times you can get it this way. I have never done it on a steam line, but pipes with various liquids in them.
Reply:If you get it to stop leaking then try putting just a couple of quick tacks over it. After a couple of tacks then you should be able to put a weld over it, you have to keep it a rather cold bead or it will just blow out again.
Reply:damn, this is scary.
Reply:"It doesn't always work, some times you can get it this way. I have never done it on a steam line, but pipes with various liquids in them."yea my guess is that while welding it diggs in too deep and the metal holding the pressure gets soft. maybe lower the heat and arc at that pointLast edited by leo10a; 11-12-2013 at 07:13 PM.
Reply:"If you get it to stop leaking then try putting just a couple of quick tacks over it. After a couple of tacks then you should be able to put a weld over it, you have to keep it a rather cold bead or it will just blow out again." yea that's the plan i was gonna try to spray it with ice water as well to help harden it faster.Last edited by leo10a; 11-12-2013 at 07:14 PM.
Reply:Ok this is a joke?I am a Steam a Fitter welder. If there is that much pressure the only way to repair your weld and make "safe" is to shut off the steam. Trying to weld over it, or tack it will not tie into the base metal enough to be a permeant fix. The leak is in the first pass and made its way through all the other weld. Turn off the steam, grind it out, and repair. That's the right way.Local 83
Reply:Originally Posted by RodBenderOk this is a joke?I am a Steam a Fitter welder. If there is that much pressure the only way to repair your weld and make "safe" is to shut off the steam. Trying to weld over it, or tack it will not tie into the base metal enough to be a permeant fix. The leak is in the first pass and made its way through all the other weld. Turn off the steam, grind it out, and repair. That's the right way.
Reply:Rodbender hit it on the head. Do it right, and save alot of headache. You have to repair the root first, or keep chasing the hole. We ALL have to swallow our pride sometimes, (it doesn't taste very good either) but it's better than spending a whole lot of time on a single pinhole problem that can be repaired in an hour.   jmho.           Rick
Reply:Originally Posted by RicksweldingRodbender hit it on the head. Do it right, and save alot of headache. You have to repair the root first, or keep chasing the hole. We ALL have to swallow our pride sometimes, (it doesn't taste very good either) but it's better than spending a whole lot of time on a single pinhole problem that can be repaired in an hour.   jmho.           Rick
Reply:Weld a thread-olet around the leak, then screw a valve or plug into the o-let.
Reply:What caused the leak in the first place? What temperature was the base metal when you welded it?
Reply:Originally Posted by RodBenderOk this is a joke?I am a Steam a Fitter welder. If there is that much pressure the only way to repair your weld and make "safe" is to shut off the steam. Trying to weld over it, or tack it will not tie into the base metal enough to be a permeant fix. The leak is in the first pass and made its way through all the other weld. Turn off the steam, grind it out, and repair. That's the right way.
Reply:I almost always carry horse shoe nails in my pockets. They are very useful for fitting and stuff. You can go ahead and try pounding one into the hole and welding around the head, but not my recommendation. What if it blows back out? What if it breaks off inside? Where is that steam going lol?  I once heard a story about a guy taking a broom handle and waving it in front of a pinhole in a steam line. It cut the broom handle in half. I also just recalled a friend of my dads getting really badly burnt by steam at work. I was going to suggest throwing quick tacks over the hole then an over lay of beads, but I think Ill pass. Be safe!Nothing Ever Got Done By Quitting, Never Give Up.
Reply:Ime no expert but that just sounds like a bad idea.PROUD   AMERICAN
Reply:Originally Posted by TimmyTIGWeld a thread-olet around the leak, then screw a valve or plug into the o-let.
Reply:Originally Posted by TSCGG13What caused the leak in the first place? What temperature was the base metal when you welded it?Originally Posted by Rock knockerIt almost seems like a troll.  Isn't this an ASME pressure pipe connection?  Wouldn't Hartford, Factory Mutual or another insurance company be on the hook, thence be involved.  A lot here I'm having trouble swallowing, especially with the talk of it (?) being a government building.
Reply:Originally Posted by Doug247I almost always carry horse shoe nails in my pockets. They are very useful for fitting and stuff. You can go ahead and try pounding one into the hole and welding around the head, but not my recommendation. What if it blows back out? What if it breaks off inside? Where is that steam going lol?  I once heard a story about a guy taking a broom handle and waving it in front of a pinhole in a steam line. It cut the broom handle in half. I also just recalled a friend of my dads getting really badly burnt by steam at work. I was going to suggest throwing quick tacks over the hole then an over lay of beads, but I think Ill pass. Be safe!
Reply:Originally Posted by Fletcher94Ime no expert but that just sounds like a bad idea.
Reply:Leaks happen. And I have worked on a few Air Force bases with giant leaks. Lol no one caredLocal 83
Reply:Well gentlemen, i got the job done and stopped the leak. It doesn't look professional nor follow standards or code, but works.How i did it:I punched the sides of the pinhole to pinch the metal and stop the leak. I was able to stop it slightly, to the point that it did not hiss. I then used a "scab" technique. Which is a square piece of metal about 2in by 2in and 1/4in thick. I place it on the center of the hole. Tacked 4 sides then began to weld around until all sides were welded. IT WORKED. Now i ran 2 more passes around the "scab". Thats 3 passes with 1/8 6010 5P. I then did 2  3/32 7018 passes and a final weave pass with 1/8 7018. Total of 6 passes, lots of wasted metal and looks ugly.I will come back to it in Feb to grind everything out and make it look professional.Lesson Learned:Obviously do a better job on the weldolet root welds. If an inspector is there, let him inspect it other than giving him an easier day.DO NOT WELD OVER THE PINHOLE OR WELD NEAR THE PINHOLE, it will NEVER WORK. At least with 140PSI behind it. The metal gets too soft and the pressure is able to push by. Thanks for the suggestions
Reply:Originally Posted by RodBenderLeaks happen. And I have worked on a few Air Force bases with giant leaks. Lol no one cared
Reply:I worked in some steam vaults on the Elmendorf Air Force Base in Anchorage, it can get pretty hot down in there. That was a cool job, though. Davis Bacon wages, we had a fab area set up pretty close to the runway and watched F-15s take off and land all day long, man those things can get loud!Nice fix on the leak!
Reply:Pretty dodgy problem... Any pressure at all pretty much rules out any puddle at all. I've seen sealing attempts made with dot welders (basically a spot welder that consumes a small ball into the surface) but never on a fluid or steam system with pressure still in it. Anyway sometimes it worked and sometimes not.The closest you could prolly get to that with an electrode would be to stab a cold rod on the pinhole and have someone switch the machine on and off very quickly or find a stud welder somewhere. The fix would look pretty goofy with a stud or electrode hanging there till next year though... Glad you got it sorted out,Matt