Fettling a roarer burner with broken nipple/stripped threads. Part 2 - cutting the tubes

Discussion in 'Fettling Forum' started by Twoberth, Jul 2, 2020.

  1. Twoberth

    Twoberth United Kingdom Subscriber

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    This is easier than it looks, and is it best to practice on a wrecked burner to gain confidence.
    This was done on an Coleman burner, where trying to remove the broken nipple as in Part 1 proved impossible.

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    Cut off the two tubes containing the nipple seat with a hacksaw. Do NOT clean up the cut surfaces.

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    The photo below shows the results of trying to remove the broken nipple threads on this burner using the technique outlined in Part 1.

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    First drill out the old nipple using a 4mm drill, then re-thread with a 4.5mm tap (0.5mm pitch).

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    Test fit and then remove a normal size nipple

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    Flux and 'tin' the two cut surfaces (Easyflo flux, Silver Flo 55 braze)

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    Flux the un-tinned cut surfaces and fit the burner together again. when you are happy with the alignment, wedge the pieces together

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    and then reheat until the braze melts all around the joints, adding more braze rod if necessary.

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    Clean up the joints and leak test underwater. (I fit a blank jet, and use a bicycle pump connected to the threaded end of the burner).

    Refit the jet, refit the burner to the stove and test.

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    IMHO, this is a much easier repair than Part 1.
     
  2. Murray

    Murray Subscriber

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    Wonderful. What would you recommend as a brazing torch - is the usual canister with screw-on burner good enough for this?
     
  3. Twoberth

    Twoberth United Kingdom Subscriber

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    I tend to use 100 propane from a 13kg tank. I have a Bullfinch torch with two nozzles but I use the large nozzle most of the time and adjust the flame via the flowrate

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    If I am out of the workshop, I do occasionally used 70/30 butane/ propane canisters with the screw on torch, but I find mine (a Taymar) produces a flame that is too fierce and oxidizing, so I adjust the air flow with a copper sleeve.

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