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Piston Rings etc

Home › Forums › Locomotives › Piston Rings etc

Viewing 5 posts - 1 through 5 (of 5 total)
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  • 8 June 2011 at 18:56 #69948
    Robert Starling
    Participant
      @robertstarling75989
      Currently machining gunmetal cylinder block for 5″ gauge Pansy but I am a bit out of touch with what is used for piston ring material these days. Originally LBSC used graphited yarn which is still available but I suspect some use silicone ‘O’ rings which are available from Chronos or Blackgates. How well do these wear ? ( I have some minor blemishes in one bore which might be the result of slag in the casting and am concerned that the ‘O’ ring might tear on this). I have also come across an article in which piston rings were made from 35% graphite filled PTFE but have no idea where to obtain this in the small quantity needed. Other modellers experiences and advice welcomed.
      8 June 2011 at 18:56 #1017
      Robert Starling
      Participant
        @robertstarling75989

        5″ Gauge Pansy

        9 August 2011 at 21:00 #73097
        nipper
        Participant
          @nipper
          Hi robert. I have used silicon ‘O’ rings in my Pansy for many years and they seem to last quite a long time certainly 300 or so miles and then they were changed because the pistons were out. If the bores are rough it may be a problem suggest honing out the bore to see if it cleans up, remember that the bore is not critical with an O ring, within reason, as you make the piston and ring groove to match the ring and the bore. Alternately I have heard of filling the blowholes with araldite and then cleaning up the bore. I know this is probably a bit late but all the best with it .
          9 August 2011 at 21:07 #73099
          JasonB
          Moderator
            @jasonb
            Not sure of the dia you need but Noggin End do the filled ptfe
             
            10 August 2011 at 07:39 #73107
            michael howarth 1
            Participant
              @michaelhowarth1
              Robert,
               
              I have used silicon “O” rings which ran well for a while but their performance petered off quite quickly. On subsequent examination, they did look sad. I spoke to the supplier, Polly Engineering, and was told that I should have used Viton rings, especially if I was using superheated steam. I took this advice and have had no problems with the Viton. Polly do a good range of Viton rings.
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