Pump tube soldering

Discussion in 'Fettling Forum' started by paul, Sep 10, 2006.

  1. paul

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    Hi guys
    Anyone care to provide an idiot's guide to soldering a pump tube back in? Stubborn NRV warranted removal, but could do with a few pointers on the re-soldering front.

    Cheers
     
  2. Doc Mark

    Doc Mark Subscriber

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    Hey, Paul,

    You might want to give Albert White (Handi Albert) a shout. He's outstanding at soldering stove parts back together, and has been very helpful in answering my own questions about such things. Good luck, and God Bless!

    Every Good Wish,
    Doc Mark
     
  3. kerophile

    kerophile United Kingdom SotM Winner Subscriber

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    Hi Paul, I'll make a start and others can join in and correct me.

    1. We will assume that you have the pump assembly fully assembled and tested. Having done this, remove the pump internals so that they do not get affected by the soldering operation.

    2.It is a good idea to make up a cylinder- holding tool from either the existing pump cap, or preferably a spare. You need to temporarily secure this cap onto a length of threaded rod, by capturing it between two nuts. Add a handle to the threaded rod. Smear some toothpaste to the threads of the cap ( this is not a joke). Attach your new tool to the pump cylinder. This will now allow you to hold and manipulate the cylinder during the soldering operation.

    3. You now need to "tin" the edges of the receiving hole in the tank, and the location area of the cylinder. You are aiming to have a freshly applied, thin layer of solder on both surfaces. This is an improtant stage in the process, get this right and you will hardly need to add any additional solder during the final soldering process. Use flux appropriately, don't use too much or you will "tin" the whole pump cylinder!

    4. I always use traditional lead / tin solders since that is what was originally used in stove manufacture, and also what I am used to. I guess there is also a question of compatibility if you are re-soldering existing joints.

    5. Be careful about the application of heat. I am assuming you are using a gas torch (or blowlamp, for the traditionalists). All stove manufacturers located their pumps right next to a leg, and if its solder melts it will drop off! Similarly, the bottom seam is adjacent and you do not want its solder to melt. Use a small, focused jet for the soldering,and consider the use of a heat-sink, like moist tissues, wired to the leg.

    6. Once you have a beautifully tinned surface on both tank hole and cylinder try a dry- assembly. It should be a sliding but tight fit. If the solder is too thick, re-melt or shave with a knife until you are happy with the fit. Now apply a thin coating of flux paste to both tinned areas.

    7. You should now be ready for the critical stage, the re-soldering. If you do not posess a third hand it is a good idea to fix the heat source and bring the work to the flame. One hand holding the tank, whilst the other steadies the pump-tube using the clever handle you made earlier.

    8. A delicate touch is needed. You want to melt the solder to secure the pump tube without over-heating the tank and melting adjacent solder joints. If you are skilled, or lucky, your previously tinned areas will melt and the magic of capilliary action will ensure that the narrow gap between tank penetration and cylinder is filled. If this does not happen you might need to apply a small amount of resin-cored solder to the joint.

    9. Once the solder melts and flows, withdraw the stove from the heat source and allow the solder to freeze. If you are using lead-tin eutectic ( electricians) solder this should be almost instantaneous. If you are using traditional plumber's solder you need to hold the joint rigid for a bit longer as the solder goes through a "pasty" stage before freezing to a solid.

    10. Switch off your gas torch, wash all the flux off the tank, remove your handling tool ( which should be easy as the toothpaste will have masked the threads and prevented them being soldered to the pump cylinder). Re-assemble the pump, put some water in the tank, close all valves, pump-up and check for leaks using soapy water round the new joint, or total immersion of the stove in a bucket of water.

    11. Hopefully the pump will work, the tank will hold pressure and you can have a celebratory beer or cup of tea.

    12. If there is a leak, empty all water from the tank, dry everything thoroughly, and apply additional solder to the leak locations which you will have marked.

    13. If there are recurring problems, set the stove aside and come back later, or on another day. Go back to the beginning of the lesson and start all over again!

    I hope this helps and I haven't forgotten anything.

    Acknowledgements to Bryan Miller, my Mentor and friend.
    Regards,
    Kerophile
     
  4. DougR

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    Today I soldered a filler tube into a Mvea No.1 doing pretty much as Kerophile described - This cured the leak and the stove now works.....

    Emboldened by this success I thought to attempt the Svea 121 which had a similarly leaky joint between the filler tube and the body.

    I can't get the bugger apart - any suggestions would be appreciated.
     
  5. paul

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    Nice one, Kerophile.
    I shall start this evening.
     
  6. fyldefox

    fyldefox R.I.P.

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    Hi Paul

    I have fortunately very little head on experience about major stove soldering, but recall a posting by I believe our good friend Sefa about masking the tank etc. where you don't want the solder to go.

    If you apply nail varnish in a neat circle, and once dry just flick a flame on it, it will carbonize and form a barrier so that a solder run will not adhere to the brass.

    Afterwards just clean off with the usual girlie stuff.

    Nail varnish ? Toothpaste ? - you may as well do it all in the bathroom ;)

    Good luck
     
  7. sefaudi

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    Dear All,

    Yes, nail varnish works great. I have never tried toothpaste but this may smell better :lol: .

    Anyway Kerophile is a great teacher I agree with him at all steps he explained definitely.

    May I suggest a point. During pump resoldering you may lose adjacent leg due to high temperature. Then you will try to resolder dropped leg. Yes this point is critical. In some past posts someone suggested to use different solders with different melting points. Yes I agree with them but finding two different solders may not possible every time. Instead during adjacent leg soldering I always fill pump hole with cold water :shock: . You may need to fill again and again during operation but this is fully guaranteed. You will prevent melting pump section solders unintentionally.

    Best regards,
    Sefa
     
  8. paul

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    Being a highly experienced pump-tube solderer, can I offer my findings too?

    1. What Kero said.
    2. Put tank on side so hole is pointing straight up - easier access right round.
    3. Have plenty of blue language ready when the pump tube falls in the tank (really).
    4. Screw the pump rod in, tie a piece of string round the knob, and tie to something above you. Holds the pump tube steady.

    Cheers guys :D
     
  9. jc

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    All good information, ya learn something new every day here. If I could ad just one point I put water in the tank to protect the bottom seam and leg joints, obviously you can't have water too close to the part you're working on - - and that means you can't have water all the way up the leg joint, but just a bit of the joint protected will prevent anything dropping off.
    Paul, if you do it with the stove in its standing position, you will better see the corect angle for the tube, and as pointed out in Kerophile's tutorial, it hopefully will 'take' without too much fiddleing or additional solder.
     
  10. fyldefox

    fyldefox R.I.P.

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    Pictures Paul, pictures :D
     
  11. sarco789

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    May I assume, then, that pump tube removal - to get its base section out of the tank - is simply a matter of doing these steps in reverse?
    Thanks again.
     
  12. kerophile

    kerophile United Kingdom SotM Winner Subscriber

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    Hi, Paul only asked me about re-assembly, so that was the question I answered....
    However, removal is pretty straight forward:

    FIRST and most Important. Wash all traces of fuel out of the tank using hot water and detergent. Then read on:

    1. Wrap and wire wet tissues to the adjacent stove foot or leg, and the bottom solder seam of the tank.

    2. Grip the handling tool you have attached to your pump-tube. Heat the area immediately around the junction of the tube and the tank.

    3. When the solder melts, wiggle the tube gently whilst simultaneously pulling outwards.

    Do the work to repair the pump tube, then follow the earlier instructions on re-assembly...

    Best Regards,
    Kerophile.
     
  13. loco7stove

    loco7stove Subscriber

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    Last edited by a moderator: Jul 2, 2015
  14. sarco789

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    What about filling the tank with water for the bottom seam?
    You'll have your fill of me before this is over with!
     
  15. hikerduane

    hikerduane Subscriber

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    I put a little water in the pump tube to keep the bottom from falling out if you heat things too much. I think some have partially filled the tank. Pieces of folded wet paper towel draped on areas you want to not unsolder works.
    Duane
     
  16. Alan

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    Kerophile,

    What is the process for the preparatory "tining" process?

    Thanks
     
  17. kerophile

    kerophile United Kingdom SotM Winner Subscriber

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    Hi Alan, welcome to CCS.
    Tinning is just a name for applying a thin coating of solder to the surface ot the components to be joined. This coating is applied to the joint areas and allowed to cool.
    The parts are then given a thin coating of the appropriate flux and brought together. Heat is applied with a torch or solder bolt, the flux and solder melt and the joint has been made. If the tinned layers have sufficient solder in them you might not even have to add additional solder.
    To tin a surface you must first get back to bare metal and clean it. You can use an emery cloth or fine file, then degrease, clean and dry the surface. A thin layer of flux is then applied, heated, and solder added.
    If the flux does its job, and the temperature is high enough, the flux melts and flows, the surface "wets" and molten solder coats the surface. Allow this to cool and you have a tinned surface.

    https://classiccampstoves.com/threads/soldering-instructions-fluxite-outfit-1930-50s.23229/

    Trust this helps.
    Kerophile.