The mystery of the perfect wick

Discussion in 'Fettling Forum' started by Sternenlicht, Sep 16, 2020.

  1. Sternenlicht

    Sternenlicht Subscriber

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    Currently I'm fettling an Optimus 99. I changed the wick, which was not bad, but little coked at the tip. After that, the flame was smaller and not that powerful as before. The wick material was the same, the size and diameter was the same, the wire was the same, but the flame is different.

    I observed the same behaviour with many stoves. I guess I changed the wick at my Enders Baby about 20 times, before I was satisfied. Same with my many Primus 71 or Juwel 34/33/84, the wick is supposed to be always the same, but the flame behaviour is mostly different.

    So, what is the receipe for the perfect wick? I think it depends on:

    - wick material (cotton in my case)
    - wick diameter (sometimes loose, sometimes tight seems to be better)
    - how deep the wick is stuffed into the tube, sometimes the wire makes some distance at the top of the wick

    Are there further points?
    What is your experience?

    Ciao, Bastian
     
  2. Sternenlicht

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    Ok, no one seems to have similar problems after changing the wick. So please tell me, whats your way to make new wicks.

    Ciao, Bastian
     
  3. JP2

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    Do you still have the old on?
     
  4. Sternenlicht

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    You mean the old wick of the 99? I have it still, but in the stove is a new one. Thinking about to bring it back.

    Ciao, Bastian
     
  5. presscall

    presscall United Kingdom SotM Winner SotY Winner Subscriber

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    @Sternenlicht Has your source for cotton been the same for each wick replacement Bastian?

    It’s happened before that material marked as cotton hasn’t been 100%. The synthetic content then melts, clogs the fibres and the flame’s worse than before.

    Try another source, maybe even a slice of flat wick from a kerosene lamp, rolled up along its length to a diameter that will fit the stove’s inlet tube.

    John
     
  6. Sternenlicht

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    @presscall
    Always the same material, I bought a mopp from 100% cotton. That will reach the next years... As far as I could see (I burned it and smelled it) no synthetics at all.
    I also took this material for the stoves which work great.
    But thanks for that advice, I will test further materials.

    But my original intension was to find out, what affects the success of changing a wick.
    So maybe I must think about, what is the function of a wick? Only fuel transport? Pressure regulaion?...

    Ciao, Bastian
     
  7. Harder D. Soerensen

    Harder D. Soerensen Denmark Subscriber

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    1) I only use wicks from the petroleum-lamps ( I buy 2 meters now and then via Ebay) - I un-twist the wick as best, as I can before using them - better a bit longer than to short..
    2) I try to copy the original wick as far as how it ends in the burner tube (distance by a small piece of brass..reusing the original brass wire if possible) - If it has a small net around the wick - I try to re-use that as well.
    3) I use a twisted brass wire to form the "backbone" inside the wick, if it doesn't have one from start.
    4) I have the same experience as you @Sternenlicht - sometimes I add an extra string - sometimes I remove one. Configuration of the wick and the height of the burner-plate can have quite an impact on the flame.
     
  8. Sternenlicht

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    Thank you Harder @Harder D. Soerensen !

    According to point 2: in some stoves the tip of the wick is touching the burner tube, in some stoves a mesh or the wire creates some distance between. Why? Is that due to evaporation reasons or for protectiong of the wick material?

    Ciao, Bastian
     
  9. JP2

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    Can we see your old one, I have had the same problem too and I did make (see picture) a wick from this product which is more similar to the original one and it work good.
    Also I did wash the wick I made from the mopp which was better but still not good enough for me. IMG_20200918_090039.jpg IMG_20200918_091300.jpg
     
  10. Sternenlicht

    Sternenlicht Subscriber

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    The original wick next to the mopp. Looks almost the same.

    Ciao, Bastian

    IMG_20200918_175643.jpg
     
  11. Ian

    Ian Subscriber

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    You could try twisted gauze bandage. I had a Russian 8R copy that had a perfectly satisfactory wick made thus.
     
  12. presscall

    presscall United Kingdom SotM Winner SotY Winner Subscriber

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    Looks can deceive. The absence of synthetic fibre from the material has to be certain.
     
  13. JP2

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    I see, mine doesn't look the same a all.
    IMG_20200918_110035.jpg
     
  14. Sternenlicht

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    I have many stoves running well, which have wicks from that material. But I will try another material. Still have some kerosene lamp wicks.

    Ciao, Bastian
     
  15. Murph

    Murph United States Subscriber

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    @Sternenlicht , the mesh builds up heat and helps vaporize the fuel, more even pressure to the jet for better burning,and the excess pressure helps build up pressure in the fount.
    Makes for a better cuppa' over all,IMO.

    Murph
     
  16. Tony Press

    Tony Press Australia Subscriber

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    @Sternenlicht

    You can test for synthetic fibres in your cotton by burning it with a flame. Pure cotton with leave no sticky black residue, whereas synthetic thread will leave sticky black lumps.

    Cheers

    Tony

    Edit: After a few years of doing this kind of thing, I use pure cotton knitting/darning thread like @JP2.
     
  17. JP2

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    To add to @Murph explanation, the hole inside the tube is not always in the middle where the importance to know where and not do any restriction with the wire.
    Here into the tube of a 123, 1970 , the hole where the wick is ; is opposite to the valve but the hole that exist to go to the jet is the same side of the valve, so , as seen on the picture, a wire not to its place could eventually make restriction to the passage and the point of the valve.
    See pictures
    Inside the tube
    IMG_20180826_225150.jpg
    By the jet
    IMG_20180826_223947.jpg
    By the valve, light by the top
    IMG_20180826_214503~2.jpg
    By the top with valve halfway
    IMG_20180826_215602.jpg
    By the valve, light coming by the tube
    IMG_20180826_214605.jpg
     
  18. Sternenlicht

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    Thank you all for your great help. I will add a mesh and see what are the differences.

    Maybe I will try some different wick types in my 71 and make some photos. But I think that will be a nice project for the winter...

    Ciao, Bastian