Primus/Optimus 535 copper cone washers

Discussion in 'Fettling Forum' started by Kalle, Apr 21, 2017.

  1. Kalle

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    Dear fellow Stovies,

    I have found out that aluminum cone washers will not last in 535 alcohol version. They will corrode just in one year quite severely, as seen on the first picture.

    I understand the washers were originally made out of copper, but they are no longer in production. So, I had to find a way to manufacture them myself.

    I made tooling of a 8mm flare connector and a 6mm cylindrical chisel that just fits inside the hole of the connector.

    I hope the pictures speak for themselves :

    Stage 1 - Cut 8,0mm long piece out of 8mm copper tubing using a pipe roller cutter
    Stage 2 - Put the piece inside the connector and form a cone of it by punching the chisel through with a hammer
    Stage 3 - Put the cone on an anvil on it's wider end down, and hammer it carefully down to a height of 6,0mm

    corroded.jpg cone1.jpg cone2.jpg cone3.jpg

    The washers I made performed perfectly. They have a little lower profile than original, so meths bowl gaskets have to be modified. As those are only needed for preventing rattle, I ended up making them out of twisted multistrand electrical wire - let's see how they last. -K
     
    Last edited: Apr 21, 2017
  2. Kalle

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    Hi, apologies.. the actual size for the chisel is 5mm.
     
  3. Kalle

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    An update, did some more experimenting, it is beneficial to anneal these before use, that is to heat them to redness with mapp torch and let cool down. They'll compress to their shape much more easily and apparently make a more reliable seal.
     
  4. ROBBO55

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    G'day Kalle. It's always good to see how members approach and fix a problem.
    Especially when the fix is relatively simple.

    Thanks for posting
    Martin