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Is bronze this hard to weld?!?

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  • Is bronze this hard to weld?!?

    Hi, All,

    I've been a lurker on this site for a while, and now I find myself pretty stumped by what I thought would be an easy project. I am trying to weld up a couple of brackets out of this bronze I got at a scrapyard -- I assume it is bronze, looks very coppery. Anyhoo, the brackets are about 14 inches by 2 inches by 1/4 inch thick, and I just need to weld on a couple of smaller pieces onto them.

    I am using an Invertec V205T Tig at 200 amps (the maximum).

    It seems like this alloy just sucks up all the heat I give it! At the suggestion of someone on the AWS site, I tried preheating the thing with a propane torch. Welding went a little better, but not by much, and OH MAN did the thing get hot.

    I am used to having a reasonably small HAZ with TIG -- are bronzes different in the way they suck up heat? I don't know what kind of alloy this is -- could it be some super heat resistant alloy (out of copper?!?). It's like I have to get just about the whole bracket up to temperature in order to do my weld. My poor air cooled torch is getting melty...

    Last edited by 49degreesnorth; 10-21-2003, 06:53 PM.

  • #2
    YES, Bronz sucks heat, possibly better than aluminum.
    It also tends to change color. You can use everdur as a filler, and probably get by with less heat. Everdur will also work with stick carbon arc, and O/A gas welding processes.


    • #3

      Thanks for the info... would welding with Everdur be more like brazing? I've not used Everdur before, but you say it takes less heat, so I must not then be melting the base metal (?).



      • #4
        Everdur is a phosphor bronz filler.
        The process is not truly a weld, in that the parent metal is not melted, and is more akin to a brazing process.
        Everdur is effective from sheet metal to large cast iron pieces.


        • #5
          I'm certainly no expert and my experience is very dated. However, I would O/A Braze Bronze.


          • #6
            I'm no expert but have had some good luck welding brass/bronze boat propellers with gmaw and silicon bronze wire.


            • #7
              As you have found the yellow metal soak up the heat rapidly. It sounds like it's not a structural thing you're doing, so I'd silver braze it. I've welded a lot of silicon bronze with MIG in spray mode, and still it takes more heat than your machine can handle. You'll fry your torch.

              Would soldering be an option?


              • #8
                OK, so I tried this again yesterday, and found that if I got the piece as hot as possible with a propane torch first and then used TIG at 200 amps to essentially heat the entire thing to about orange hot that I could back off on the heat and weld normally until the torch got too hot.

                Brazing and soldering could be done -- but now I'm halfway there!

                Anyone out there know: I'm using silicon bronze rod to weld this thing; if it is made of pure copper are my welds doomed? Also, what if it is magnesium bronze or aluminum bronze?

                I think I won't buy bronze from the junkyard anymore!

                Thanks for all your help -- this is a great site!



                • #9
                  So many alloys now loosly called bronze.
                  Yours isn't old zinc copper alloy as your not complaining about bubbles or zinc fumes.


                  • #10
                    Zinc bronze would be brass, right? I've welded that and it is tricky, as the zinc seems to burn away. If this stuff hasa zinc in it then it doesn't have much, as it is very coppery in color.



                    • #11
                      The stuff is copper, after all!

                      I compared its color to a freshly wirebrushed piece of copper.

                      And I managed to bend the thing by standing on it. Not much good for a bracket!

                      Thanks for all your help!



                      • #12
                        yeah,I suggest brazing it if you haven't already scrapped the pieces by now.Brazing is always an option and yes don't think that brazing is not strong as welding because it is probaly stronger than most average joe kinda guy's welds


                        • #13
                          Well, being copper you could Silver Solder it. Silver Solder is a low temp form of brazing and is compatable with copper. Only problem with copper is it oxidizes something godawful when you really put the heat to it but that can be cleaned when your done.

                          Good luck with it!