valve washers – Petromax part np. 193

Discussion in 'Fettling Forum' started by Piotrek, Nov 28, 2023.

  1. Piotrek

    Piotrek Czech Republic Subscriber

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    Dears,

    Attached photo of two types of valve washers – Petromax part np. 193.

    Anybody can advise how to restore the older version of Petromax part np. 193 (approx. 1940), so I would not have to replace it with the modern one? There is that metal part in the middle of the washer and I am not sure how to replace the soft, rubber part for Viton. I can just inset Viton washer at the other end and insert the part upside down, but I am not sure if this would be working/safe when conducting rod pushing the soft rubber without metal center.

    All the best,
    Piotrek


    1.jpg 2.jpg 3.jpg
     
  2. WimVe

    WimVe Subscriber

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    I would replace the old washer with a new viton one.
    Getting the dimensions right may be a hassle. Shape wise it is a washer with a hole in the middle.

    The old style with the metal center was developed to prevent the valve push rod of damaging the soft rubber.
    I guess that after some years the valve pip became a simple replacement part.
     
  3. Piotrek

    Piotrek Czech Republic Subscriber

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    Thanks Wim for info.
    I will try to punch a washer and drill a small hole to fit inside. If not successful then I will try to put it upside down with new viton gasket without the hole and supporting centre. There is only small spring holding it against the rod tip, so damage risk is pretty low in my opinion.
    Piotrek
     
  4. ROBBO55

    ROBBO55 Subscriber

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    @Piotrek
    The washer can bt replaced, it's just a bit fiddly.
     
  5. Madras

    Madras United Kingdom Subscriber

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    @Piotrek
    It is possible to make these seals .
    I bought some viton cord approximately 5 mm diameter .
    I put a length in my mini lathe and drilled/ bored a hole using a 1 mm bit .
    I then used a fine scalpel to cut them approx 2.25 mm,
    This left them a fraction over size so when they were put into the brass carrier a little sanding with a fine rubbing paper had them fitting just right .
    Marten
     

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  6. MYN

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    A mini lathe certainly makes things a lot easier. Drilling a hole at the centre of a tiny pip can be quite a hassle.
    The protective metal centre indeed makes pip replacement a little fiddly if you don't have the right tools.
     
  7. Piotrek

    Piotrek Czech Republic Subscriber

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    Thank you guys for advices. My "workshop" is located on my family dinning table :), but now I am pretty sure that I will be able to do these seals/pips.
    regards,
    Piotrek
     
  8. Madras

    Madras United Kingdom Subscriber

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    @MYN
    Yes the lathe was a great help with making the seals.
    It is one of those mini lathes from eBay and mass produced in China .
    It is strong enough to cut plastic and rubber but I have doubt if the little motor is big enough to work brass or other soft metals .

    @Piotrek
    I also bring the work in to living room when it gets cold out in the shed .
    Hope the seals work for you .
    Marten
     

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