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Soldering with oxy acetylene

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  • Soldering with oxy acetylene

    I got sent to Switzerland to integrate a system we built. I found a leak on a 3" copper line and need to repair it. Unfortunaetely, they don't do much copper soldering. The only setup I could get was an oxy-acetylene cutting torch.

    Is there a way to dial in the torch without getting black soot everywhere?

    Todd

  • #2
    Re: Soldering with oxy acetylene

    Originally posted by bentod View Post
    I got sent to Switzerland to integrate a system we built. I found a leak on a 3" copper line and need to repair it. Unfortunaetely, they don't do much copper soldering. The only setup I could get was an oxy-acetylene cutting torch.

    Is there a way to dial in the torch without getting black soot everywhere?

    Todd
    I have my passport at the ready and am prepared to help you fix the problem.
    On a more serious note turn up the oxygen more so that the inner flame is blue and that there is no orange in the flame.
    Be careful heating up the copper with that torch, you will need to lift the torch away to regulate the heat.
    Also make sure that there is no water in the pipe as this will turn to steam and blow out the solder.

    Simon

    Comment


    • #3
      Re: Soldering with oxy acetylene

      Originally posted by bentod View Post
      I got sent to Switzerland to integrate a system we built. I found a leak on a 3" copper line and need to repair it. Unfortunaetely, they don't do much copper soldering. The only setup I could get was an oxy-acetylene cutting torch.

      Is there a way to dial in the torch without getting black soot everywhere?

      Todd
      todd, didn't you hire a plumber off this site 6 months ago

      send him out there, better yet send me

      so here's the issue.

      oxy/ accy burns very clean when you have the best neutral torch adjustment. it also burns at approx 6300 degrees

      so you need to adjust to a nice neutral flame/ blue cone and then just feather the torch away from the copper. on 3'' i would use a rosebud tip to spread the heat and use the outer flame tips, not the blue cone.

      sorry just re read the post. you have a cutting torch what ever you do, don't squeeze the cutting / oxy lever on the torch head. still adjust the torch as i mentioned and feather the torch head away from the copper. don't overheat the copper.

      unfortunately the best way to fix that joint is to actually remove it from the line and re clean and re flux.

      since you're using flux that's non water soluble, you might have better luck that we do with water soluble flux.

      i think your #1 man can walk you through it.

      good luck, if all else fails, you're in switzerland

      rick.
      phoebe it is

      Comment


      • #4
        Re: Soldering with oxy acetylene

        Yeah, why didn't our #1 guy come instead of me?

        Ok, I got the flame dialed in. I haven't had to run oxy-acetylene since high school (long time ago). Fortunately, they had some braizing tips.

        I did take the joint completely apart and cleaned it. In the end, it went together nicely and doesn't leak. If the fitting had not been on the end of the line, I would have been in big trouble. The unit is wrapped in insulation and snugly installed in a larger system.

        Thanks for the response.

        Todd

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        • #5
          Re: Soldering with oxy acetylene

          Braze instead of solder ?

          Comment


          • #6
            Re: Soldering with oxy acetylene

            This might be totally out to lunch, but couldn't you just not turn on the oxygen side of the regulator and only burn acetylene? That would be kinda like using a b-tank torch wouldn't it? Just a thought.

            Comment


            • #7
              Re: Soldering with oxy acetylene

              Originally posted by Marklar89 View Post
              This might be totally out to lunch, but couldn't you just not turn on the oxygen side of the regulator and only burn acetylene? That would be kinda like using a b-tank torch wouldn't it? Just a thought.
              not really.

              a b-tank is actually an air/ acetylene torch. it has a mixing chamber that sucks in air and mixes it to the proper mixture. otherwise all you'll get is carbon floaters

              rick.
              phoebe it is

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              • #8
                Re: Soldering with oxy acetylene

                and why didn't rick try to push pro press on this one
                Charlie

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                • #9
                  Re: Soldering with oxy acetylene

                  Originally posted by HVAC HAWK View Post
                  and why didn't rick try to push pro press on this one
                  charlie, if you only knew

                  i'll explain it at the roundup

                  rick.
                  phoebe it is

                  Comment


                  • #10
                    Re: Soldering with oxy acetylene

                    Not a pro plumber by any means, but I've been gas welding, brazing and soldering for a loooong time.

                    There's a couple of points I want to make. A neutral flame is very important. To much oxygen and you form oxides that can get in the way of the solder wetting and flowing properly. Too much acetylene and you introduce carbon that will have about the same effect. Neutral is when the middle light blue cone (called the "feather") just barely disappears. If you have an excess of oxygen, sometimes it's hard to see the color depending on the light. One trick is to look at the length of the inner cone - it shortens up when you get an excess of oxy. Also, you can hear the flame start to hiss noticeably louder when you get to an oxidizing flame. In either case, dial back the oxy a bit.

                    The thing about soldering plumbing with oxy-acetylene is, the flame is really far too hot for the job. If you move the flame all or mostly around the joint to heat evenly, no problem. But sometimes your access isn't very good. With propane, the rate of heat input into the joint is fairly slow. The copper, an excellent thermal conductor, has enough TIME to conduct heat around to the other side of the joint and it all ends up pretty isothermal. With MAPP, you have to be a little more careful to heat evenly but it's still mostly ok. With oxy-acetylene, it's real easy to overheat the joint and fry the flux right in the area where you're directing the flame. Even though copper is an excellent heat conductor, the flame is SO hot that it's easy to get a large gradient - you overheat one side of the joint and are still too cold on the other side. A problem, epecially if you can't see the backside too well. The solution is... be gentle and purposely go slow, veerrry slooow, bringing the flame away from the joint frequently. This allows a little more time for the heat to conduct around to the back side, and keeps you from cooking your flux. Which of course only happens on the joint needing the most and most painful disassembly to fix.

                    Rick is also right on regarding the rosebud. It might seem counter to idea of avoiding overheating, but I've had better results with a big flame held way back. The little tips put that 6000 degrees in a very small area of the joint. Easy to light stuff on fire with a rosebud, though. The cutting torch has a pretty big spread... should be ok.

                    As I said, I'm very comfortable with oxy-acetylene and have used it for sweating -- but you do have to be more mindful of overheating.

                    Good luck.

                    -Andy
                    Last edited by Andy_M; 06-16-2009, 10:34 PM.

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                    • #11
                      Re: Soldering with oxy acetylene

                      Just buy an air actelyne hand piece and you will be golden ...

                      Dave

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