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Power for model steam engine..

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  • #16
    Thanks for all the suggestions and interesting information.

    All in all I think a dry ice unit is almost practical for one of our Lego trains!

    The dry ice would be in the red battery car.

    P.S. This pic is "clone Lego" but was a handy photograph to find.

    Click image for larger version  Name:	150202c-lego-classic-7722-steam-cargo-train-set-1985.jpg Views:	0 Size:	139.0 KB ID:	1878194
    Last edited by The Artful Bodger; 05-29-2020, 05:11 PM.


    • #17
      CO2 at room temperature comes to about 900 psi IIRC- not unmanageable. Takes a pretty good valve to keep that under control, but again not hard to do. But you probably won't keep the gas in the bottle between uses, not for more than a few days or a week or two anyway. Maybe the air gun guys have a handle on that with their small tanks. I had a CO2 fire extinguisher that I bought used, still had what felt like some slosh in it. After I played with it, the charge slowly leaked away and it was empty next time I wanted some CO2. For my limited uses it would have been a lifetime supply, but now it's just an empty tank taking up space in the shop.

      Some years ago I read about a tank which would come apart and allow you to put chunks of dry ice in it. Screw it together and let it warm- there's your pressure. This one was steel, and capable of containing the full pressure safely, so theoretically you could have pressure now or two weeks from now- depending on how good the seals were.

      Of course you would need a source for dry ice that is convenient enough. In the late 60s we could get dry ice from our local milk plant, but that dried up. When I was in Africa it was easy to get dry ice- at the time things weren't saddled with regulations. Makes me wonder if there isn't a better way to do it- perhaps generate it chemically for the short duration of demonstrating a model engine.
      I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-


      • #18
        Originally posted by The Artful Bodger View Post
        ... All in all I think a dry ice unit is almost practical for one of our Lego trains!
        I never encountered dry ice for sale during my New Zealand days. Is it available in Ashburton?

        Allan Ostling

        Phoenix, Arizona


        • #19
          If I am stuck I can get dry ice couriered from Auckland! I can get it from BOC (welding supplies) in Christchurch, just take my 'esky' and Visa card.

          There is probably someone in town using it. The frozen vegetables factory, one or other of the meat works, engineering shops, hospital, veterinary etc.
          Last edited by The Artful Bodger; 05-29-2020, 05:58 PM.


          • #20
            Originally posted by PStechPaul View Post
            [SIZE=14px]I have seen some articles about using a microwave magnetron to vaporize small quantities of water into steam to power an engine. Of course you would need a source of electrical power for the magnetron, so this would just be a novel electric motor that does not use magnetism to produce mechanical energy. There are some claims that such an arrangement can be connected to an alternator and thus be self-powered, but I would challenge that assertion. The only way I could see such a system produce net output power only from water would be if a tiny bit of fusion would be produced on the deuterium or tritium in the water. Nevertheless, it seems like an interesting project.....
            Paul, I think you just described the Mr Fusion coffee maker from Futurama.... 😁

            Chilliwack BC, Canada