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Need Help With Brass

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  • Need Help With Brass

    Here is the job I am facing once the weather turns warmer, where my manager sees time in my schedule, I have no idea. We have about 45 - 50 fire hydrants left in town where the threads on the outlets do not match up to the new fire trucks. All the threads are brass on all hydrants. They are buying adapters to fit the hydrants so the fire department can just hook to them without using their own adapters, these adapters are brass also. The barrel of the hydrants is cast iron so the brass insert was molded in somehow when the hydrant was made. The newer ones have set screws and are removable. They want me to braze or weld the $200 adapters fast with about 1 inch of weld to prevent them from coming off, theft or otherwise. The brass is about 1/4" thick and the threads stick out about 1-1/2" past the barrel of the hydrant. They have a generator, stick welder, mig welder, torch outfit that I can easily mobilize to do the task.

    Can anyone offer any suggestions on what the best methods would be or should I get a list of compounds before hand that were used in the manufacturing of these items ? I know its going to be expensive but then looking at the initial cost of the adapters - $200 x 50 = $10,000, welding supplies will be cheap

  • #2
    Braze 'em

    I would suggest you braze them with either oxy/acet or a tig machine.

    You won't have a metals incompatibility problem and the strength will be there.

    Just my $02.

    Comment


    • #3
      Originally posted by Old Sporty View Post
      I would suggest you braze them with either oxy/acet or a tig machine.

      You won't have a metals incompatibility problem and the strength will be there.

      Just my $02.
      how do they use a tig machine to braze or weld brass? or even copper? do you use brass filler ? and what tungsten would you use?

      Comment


      • #4
        I 2nd the torch weld. But is there any rubber packing in the hydrant that will melt or burn? You could do a little vee grind between the brass and the cast iron and fill it in with braze...Bob

        Comment


        • #5
          Originally posted by aametalmaster View Post
          I 2nd the torch weld. But is there any rubber packing in the hydrant that will melt or burn? You could do a little vee grind between the brass and the cast iron and fill it in with braze...Bob
          The only rubber would be where the stem sticks out the top of the hydrant or about 4 - 5 feet down the barrel where the hydrant hooks onto the water main, there is a rubber gasket around the plunger that seals off the water.

          The one concern I did have with brazing is with brass being a good conductor of heat, would it transfer too much heat to the cast iron causing it to crack ?

          Comment


          • #6
            I take it the adapters thread onto the existing fitting on the hydrant? Dont shoot me for being in left field here but, why not use something along the lines of Loctite High Strength Bearing Mount with Primer N on the threads before assembing it? With the ammount of force required to break it free, its basicly permanent, and helps seal. We use it at work for all of out large fittings. Just a thought.

            -Aaron

            Comment


            • #7
              I could be wrong, but you can tig brass can't you? Pretty sure the big whistle my shop teacher was working on was brass, and the entire round end cap was welded on.

              Don't know if it would be the best for your application as the threads should be watertight on their own. It sounds like you just want to keep it from coming off, if thats the case the threads should make an excellent fit for brazing. Got any pictures?

              Comment


              • #8
                Originally posted by mikesparks View Post
                how do they use a tig machine to braze or weld brass? or even copper? do you use brass filler ? and what tungsten would you use?
                Brazing with Tig is the same as using o/a. The tig torch is just the heat source. I'm no expert at this, but have done a little bit of it. Heat control is the main thing to watch. Don't want to boil the brazing material and don't want to overheat the base material. Requires a good touch.

                I'm sure there are some of the long time weldors here that have run across this in the past. Just get some scrap and give it a try. Another skill to learn.

                Comment


                • #9
                  Brazing with a o/a torch would be best. make sure that there are not any other materials in the hydrant that can be hurt by the heat. if the fitting can be removed from the hydrant before brazing, that would be a plus.

                  Comment


                  • #10
                    If these are just thread on adapters I'd be inclined to
                    heat the adapter up to say 350-400 degrees and thread it
                    on while hot. Would suspect when cooled it would not be
                    able to be unthreaded with out breaking the original stub
                    out of the cast barrel.
                    Dave P.

                    Comment


                    • #11
                      Do not try to TIG brass, the zinc will boil out, ruining your day. I ruined a good valve this way.

                      The way I would do this is an o/a setup using silver brazing rod. My second choice would be red loctite.

                      BTW, welcome to the board, Jerry. I moved up to top floater when you retired. Moved to permanent 1st this year.

                      Comment


                      • #12
                        get some silicon bronze electrode ECuSn (stick or wire, i'd use stick) zzzzzzzt, zzzzzt,
                        done.

                        Comment


                        • #13
                          Originally posted by Aerometalworker View Post
                          I take it the adapters thread onto the existing fitting on the hydrant? Dont shoot me for being in left field here but, why not use something along the lines of Loctite High Strength Bearing Mount with Primer N on the threads before assembing it? With the ammount of force required to break it free, its basicly permanent, and helps seal. We use it at work for all of out large fittings. Just a thought.

                          -Aaron
                          I was going to suggest the same thing Bearing mount green locktight or High strength red made for large diameters. a little acetone and a hydrant wrench and that adapter will be on there forever.

                          Comment


                          • #14
                            hmmmmm,
                            LockTite $300 per quart (these are loose threads, for easy hook up, you'll need a lot of LockTite)
                            ECuSn $20 per 5#
                            drive up, remove cap, squirt LockTite, thread on adaptor, come back next day to replace cap (you sure don't want no stray LockTite lockin' that cap on)
                            drive up, remove cap, thread adaptor, weld, cap.

                            gee, cheaper and easier to weld.

                            Comment


                            • #15
                              My choices would be:

                              1) Low temp flux coated silver, a little pricey, but strong as all get out and flows like water.

                              or

                              2) Brush and flux the treads and use plain old 50/50 solder(or 80/20, or 90/10 or 95/5, whatever) and sweat it just like copper plumbing fittings. A small rosebud should work well to get enough heat around the fitting to flow the solder through the threads.

                              Just my 2c.

                              Good luck, let us know how it works out.

                              Comment

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