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Brazing copper to steel????

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  • Brazing copper to steel????

    Good Morning Guys!

    I need some guidance. Allow me to explain.

    I have a copper strip that’s 2” wide and 0.400” thick. The copper strip has been completely “tinned” ….. most likely with ordinary rosin core solder beings that the copper strip was cannibalized from a large electrical breaker box. I am making a stand which, for my purposes, will require that I cut the long copper strip into three equal parts. I will assemble these copper strips on a 1 sq ft piece of plate metal (steel) that’s .250” inches thick and arranged the copper strips 120 degrees apart (forming the base for a tripod). I would like to braze the copper strips to the steel plate.

    1. Can thick copper, such as that described, be brazed to steel using ordinary brazing rods?
    2. Since the copper strip is coated with solder, and provided that copper can be brazed to steel, will the presence of solder hinder/prevent me from brazing the copper strip to steel?

    Harold
    Last edited by hwingo; 10-17-2013, 11:23 PM.
    For those having fought for it, Freedom has a flavor the protected will never know.
    Freedom is only one generation away from extinction.

  • #2
    If I were going to do that, I would remove all of the lead based solder from the copper parts before I tried to braze them to the steel. You can do this with either some solder wick or mechanically removing it. If you leave the solder there, you will most likely have a real mess when you try to braze it. Not to mention the lead fumes you will create.

    Comment


    • #3
      Gazz,

      Rather than braze, could I use a solder such as StayBrite or Hi-Force 44 silver bearing (used to "sweat" front sights on firearms)? I know I will start a "fire-storm" and receive a plethora of OT replies by saying this, BUT, at this stage of my life I am not too concerned with Pb fumes. I am more concerned with constructing the stand.

      Harold

      As an afterthought, could I use acid core solder? Can acid core solder "tin" steel?
      h.
      Last edited by hwingo; 10-17-2013, 10:16 AM.
      For those having fought for it, Freedom has a flavor the protected will never know.
      Freedom is only one generation away from extinction.

      Comment


      • #4
        I am not sure about how something like the Hi-force 44 or staybrite will work with the old lead solder but I would guess that they will simply mix or alloy together once you have reached the proper temperature. To be sure, clamp your copper piece in a vise and either file or scrap the lead solder that is there off. With nice clean parts and there should be no mystery. I have a small bottle of soldering fluid which I believe is some kind of acid that works great on steel for soft solder but I do not know if it is available anywhere.

        Comment


        • #5
          Clean off the solder and braze with silicon bronze filler metal. Available in rods or wire.
          It's made for attaching copper to steel, along with attaching dissimilar steels.

          http://store.cyberweld.com/haersibrmigw.html

          Comment


          • #6
            Originally posted by Highpower View Post
            Clean off the solder and braze with silicon bronze filler metal. Available in rods or wire.
            It's made for attaching copper to steel, along with attaching dissimilar steels.

            http://store.cyberweld.com/haersibrmigw.html
            Hi Highpower,

            Ok, let me get this straight. When I think of brazing, I think of using OAc and a fluxed rod. I will need to visit my local welding supply and request Harris silicon bronze filler rod if using OAc. I do have a MIG so the link you sent is suggesting that I can *weld* brass to steel (which is good to know) and even weld copper to steel but preheating may be necessary. Have I said this correctly?

            Since this is likely to be a "one time thing", my first inclination is to purchase a few rods rather that buying a roll of wire that may never be completely used. On the other hand, I really like MIG welding and the control I usually have when making a run. When I braze, "stuff" runs everywhere ..... but it's brazed and I have no parts-failure.

            Thanks for pointing me in that direction. Lets give that the "ole college try" and see what happens.

            In passing, have you had experience with Brownells HiForce 44 silver solder? I've had mixed results and it's probably because I don't know what I am doing. I have a hard time getting the solder to "wet or squat". I've tried various fluxes and the one that seemed to "wet" better than others was 20 Mule Team Borax. I simply add a bit of water to the powder, mixed to consistency, apply borax to the parts, apply heat, and *try* to solder with HF 44. Sometimes I have been successful and other time a total failure. Any suggestions?

            Much appreciated.

            Harold
            For those having fought for it, Freedom has a flavor the protected will never know.
            Freedom is only one generation away from extinction.

            Comment


            • #7
              Originally posted by hwingo View Post
              Gazz, Rather than braze, could I use a solder such as StayBrite or Hi-Force 44 silver bearing (used to "sweat" front sights on firearms)? I know I will start a "fire-storm" and receive a plethora of OT replies by saying this, BUT, at this stage of my life I am not too concerned with Pb fumes. I am more concerned with constructing the stand. Harold As an afterthought, could I use acid core solder? Can acid core solder "tin" steel? h.
              The Staybrite and that class of soft-solder is compatible with all the older lead based solders. At soldering temperatures you don't have to worry about lead fumes.

              I have brazed with silfos right into soft soldered joints.. not the best policy, but it did work. Yoiu will have lead fumes doing this.

              You can tin the steel with any kind of flux, the acid paste fluxes will likely be the most successful. I like NoCorode flux.

              If the soft solder is strong enough for your application, I would just tin the steel, clean off the residue, then apply a light coat of flux before you solder on the tinned copper, position the copper pieces and heat from below. Keep the flame off the joint. That way you won't burn the flux.

              The solder that remains on the tinned pieces will be enough to complete the joint if the fit up is good. Soft solder is all that is required unless you have a crappy fit or the piece is subjected to high temperatures.

              paul
              Last edited by ironmonger; 10-17-2013, 11:54 AM.
              paul
              ARS W9PCS

              Esto Vigilans

              Remember, just because you can doesn't mean you should...
              but you may have to

              Comment


              • #8
                Regardless of your age you should take care with lead. Very small amounts can do damage or make life uncomfortable. I'd hate to spend my last year of life with a plumber's headache.

                Comment


                • #9
                  Just so I have this straight -- your copper is just under 1/2 an inch thick and your steel is 24 gauge (about half as thick as a DVD)? If that's correct, I'd tin the steel and solder the joints.
                  Kevin

                  More tools than sense.

                  Comment


                  • #10
                    If the goal is to just attach the copper to the steal and the finished piece will not be subjected to heat I would just use an epoxy and glue the two pieces together.

                    Comment


                    • #11
                      Originally posted by KJ1I View Post
                      Just so I have this straight -- your copper is just under 1/2 an inch thick and your steel is 24 gauge (about half as thick as a DVD)? If that's correct, I'd tin the steel and solder the joints.
                      The copper is .400" thick and the steel is 1/4" thick.

                      Harold
                      For those having fought for it, Freedom has a flavor the protected will never know.
                      Freedom is only one generation away from extinction.

                      Comment


                      • #12
                        Originally posted by portlandRon View Post
                        If the goal is to just attach the copper to the steal and the finished piece will not be subjected to heat I would just use an epoxy and glue the two pieces together.
                        The goal is to attach the three pieces of copper to support 3 copper legs which will eventually support a small table-top of either SS or Polycarb. Haven't yet decided on the top but it will be a weight bearing surface (light weight mind you) and will be used outside ..... sometimes at 40 below zero. Burrrrr!! That just served as a reminder that cold weather is not far off.

                        Harold
                        For those having fought for it, Freedom has a flavor the protected will never know.
                        Freedom is only one generation away from extinction.

                        Comment


                        • #13
                          There are a few misconceptions in this thread. Staybrite and HighForce 44 do not contain lead. They are approx. 96% tin and 4% silver. They melt around 600deg. F . Borax is not a suitable flux for either since it melts at about 1200 deg. F. (It's a brazing flux) Ordinary liquid zinc chloride soft solder flux is correct and it works perfectly on steel, copper, brass. Just don't overheat it. Even an ordinary propane torch will burn the flux and oxidize the solder if you let it.

                          RWO

                          Comment


                          • #14
                            Originally posted by RWO View Post
                            There are a few misconceptions in this thread. Staybrite and HighForce 44 do not contain lead. They are approx. 96% tin and 4% silver. They melt around 600deg. F . Borax is not a suitable flux for either since it melts at about 1200 deg. F. (It's a brazing flux) Ordinary liquid zinc chloride soft solder flux is correct and it works perfectly on steel, copper, brass. Just don't overheat it. Even an ordinary propane torch will burn the flux and oxidize the solder if you let it.

                            RWO
                            RWO, You are absolutely right about the borax... 40+ years of soldering copper pipe led me to say 'any type of flux'... I meant any type of flux suitable for copper pipe. Nocorde, laco, or any of the zinc chloride based fluxes. The liquid's I don't use too often, but they will work as well.

                            All of the low temp solder fluxes have a limited amount of chemical activity, so you need to clean the surfaces and bring them to temperature and add the solder, if you heat the paste fluxes to long the oily carrier remains but the chemical usefulness is gone.

                            Soft soldering (low temperature) is not a big deal if you clean the surfaces mechanically, and flux immediately thereafter. heat the surface and add the solder. Heating from the bottom or opposite side help to keep you from burning the flux.

                            Harold, you might want to practice tinning the steel on a piece of scrap to get the hang of tinning it. The copper will not be difficult to tin.

                            paul
                            paul
                            ARS W9PCS

                            Esto Vigilans

                            Remember, just because you can doesn't mean you should...
                            but you may have to

                            Comment


                            • #15
                              Originally posted by hwingo View Post
                              Since this is likely to be a "one time thing", my first inclination is to purchase a few rods rather that buying a roll of wire that may never be completely used. On the other hand, I really like MIG welding and the control I usually have when making a run. When I braze, "stuff" runs everywhere ..... but it's brazed and I have no parts-failure.
                              Are you using a Torch Mate on a Miller? If so you do not need to buy one of the big spools, but just a small one that will fit in the feeder build in the gun.

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