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Discussion Forum

solder won’t take

merlvern | Posted in General Discussion on November 21, 2005 08:31am

first, i’d like to admit that i’m an idiot. but please help me out anyway.

i have re-done all the plumbing in my basement from galvanized to copper. i have one joint that just won’t stop leaking. it is on the bottom end of brass shut-off valve coupled to a copper 1/2″ pipe. the valve and pipe are angled down at 45 degrees, so essentially i am soldering up hill. no matter how much i try to get this joint to seal, another pin-hole leak appears in the joint. by now, there is no flux left in the joint so the solder won’t flow, and i just have a bubbly mess of solder. i also don’t want to take apart this whole section to re-do the one joint.

any ideas or techniques?

thanks

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Replies

  1. WayneL5 | Nov 21, 2005 09:04pm | #1

    There is no way to do it without dismantling the joint, cleaning it, and starting over.  I'd recommend starting this joint again with new fittings.  The key is cleanliness of the joint.  Use a brush made for cleaning fittings or clean steel wool, flux both fittings carefully to coat the entire joint, but make the coating of flux thin (don't gob it on).

    If your propane tank is running low, try a fresh tank because a weak flame can hurt, too.

    If you are dripping water out the joint you must stop it.  A piece of white bread without the crust stuffed up in the pipe will do the trick.  Then remove the strainer from the nearest faucet and flush it out.

    1. Scott | Nov 21, 2005 09:10pm | #2

      Ha. I'd forgotten about the white bread trick.

      Merlvern: The only thing I'd add to Wayne's post is that if there is ANY water in the vicinity of the joint it will cool the pipe and the solder won't flow. All water must be evaporated away from the area.

      Scott.

      1. pjmcgarvey | Nov 21, 2005 09:52pm | #5

        I've tried bread, shop vac'ing the water out... if you see steam, that's still not good enough, you'll still have a pinhole leak somewhere of course. 

        This is why I hate plumbing, doing new work must be so much easier b/c of dry, clean pipes.

        I've read that instant solder can work even if the joint is still somewhat wet?

        PJ

    2. merlvern | Nov 21, 2005 09:44pm | #3

      i was afraid of that....how do i take it apart?....it's soldered on the other end. should i just heat it till the metal drips out?thanks for all the help too!

      1. PatchogPhil | Nov 21, 2005 09:50pm | #4

        You could also cut the pipe.  A couple of pictures would help.

        1. merlvern | Nov 21, 2005 10:08pm | #6

          i didn't mention....the upstream side of the "valve" is the "house supply" (i didn't design this). it's going to be VERY hard to get that section dry.the plumbing in this section goes like this:house main, 3/4" T to 1/2" pointing 45 degrees down, 2" section of 1/2", brass valve, 1/2" copper....and so-on. the leak is on this last section.

          1. RalphWicklund | Nov 21, 2005 10:23pm | #7

            Cut the mess out and discard the valve. Start over with new stuff on the bench. The brass is your bugaboo, being a large heat sink.

            Solder the 1/2" nipples on each side of the valve while you have it on the bench in front of you, then solder that assembly into the system. Measure the nipple lengths carefully and you will minimize the number of additional joints you have to make up.

          2. merlvern | Nov 21, 2005 10:36pm | #8

            ok,.....big breath, here i go, i'm going to re-do the whole thingamajigger.thanks everybody!!!!!!!!!wait,....one last try at laziness...what about this "instant solder"?

          3. junkhound | Nov 22, 2005 12:21am | #9

            cut the pipe, unsolder from valve, install union. Cut 2 pipes and install 2 unions if need be.

          4. pjmcgarvey | Nov 22, 2005 03:12am | #13

            Well, I guess it's kinda like JB Weld, but never tried it.  Just heard of it.

            PJ

          5. dutchblue | Nov 22, 2005 05:11am | #17

            house main, 3/4" T to 1/2" pointing 45 degrees down, 2" section of 1/2", brass valve,

            Just out of curiousity, what is the pipe made up of from the main to the brass valve?  The reason I ask is that you want to make sure that you have a dielectric union between the copper and galv.

          6. merlvern | Nov 22, 2005 05:28am | #18

            copper...thanks for the concern dutchblue

  2. ZooGuy | Nov 22, 2005 01:32am | #10

    >>no matter how much i try to get this joint to seal, another pin-hole leak appears in the joint

    I am not a plumber but I read this hint on this board once: if the joint is constantly making new pinholes in the hot solder, try opening a valve somewhere -- the hot air in the pipe is trying to escape and, finding no respectable opening, makes its own.

  3. MSA1 | Nov 22, 2005 01:40am | #11

    First of all, you did take the guts out of the valve right? I agree with the others, just cut out the bad spot and start over. I always find it very difficult to resolder a fitting.

    BTW if its a ball valve just open it since you cant get the guts out.

    1. PatchogPhil | Nov 22, 2005 01:46am | #12

      Somewhere,  I was warned to not fully close a ball valve when "sweating" it on.  Close the valve and then back it off just a bit.  Supposed to be a safeguard preventing it getting "stuck" somehow during the soldering process.

       

  4. VAVince | Nov 22, 2005 03:55am | #14

    The best advise is to take apart and redo. However, I worked in plumbing years ago and a guy I worked with would take and use silver soldier to fix a leaky joint without taking apart. He said that the regular soldier had been over heated and bubbled and crystlized. The silver soldier works at a HIGHER heat and will bond to the outside of the fitting as well as the inside. I dont know, maybe worth a try if you happen to have some. By the way you need higher heat such as mapp gas



    Edited 11/21/2005 8:02 pm ET by VAVince

  5. JohnSprung | Nov 22, 2005 04:30am | #15

    Another thing to consider, depending on the geometry of the situation:  Scrap the sweat valve, sweat on NPT thread adapters, get a threaded valve, and assemble using wrenches, just like with threaded pipe.

    That way you don't have the heat sink effect of the heavy valve body, and you don't have to worry about toasting the plastic or rubber parts of the valve. 

     

     

    -- J.S.

     

    1. merlvern | Nov 22, 2005 04:43am | #16

      thanks everyone....you guessed it! left the water on on the upstream side of the valve, i guess if the brass is a heat sink, brass with a cold side even more so.live and learn.....i REALLY appreciate all the help

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