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Re: [Distillers] First still

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  • Mike Nixon
    bigwhitehunters wrote: Subject: [Distillers] First still Hi, I am about to build my first still and have some questions. I am thinking of building a compound
    Message 1 of 2 , Sep 2, 2002
      bigwhitehunters wrote:
      Subject: [Distillers] First still

      Hi, I am about to build my first still and have some questions.
      I am thinking of building a compound still with vapour management, as
      per 'The Complete Distiller'. If the Liebig condensor core is
      narrower than the head diameter, will this not limit my range of
      reflux rates? ie. prevent 50% reflux for stripping.
      Hi James,
      In a word, no. It is noted in the book that when a given vapour is offered
      two similar for paths to follow, then relative aperture alone is the
      governing factor, and gate valves provide a means of controlling this. This
      was what prompted initial investigation into vapour management. However,
      when the geometry of the paths was changed, then it became evident that the
      gate valve was not the only factor controlling flow, and that composition of
      the vapour also played a significant role. This led to the design published
      in TCD, which has one path going up to the reflux condenser and the other
      going down to a product condenser. A Liebig was chosen for this because it
      was simple to make and also had the advantage of cooling the product. The
      role of the gate valve became more like that of a needle valve in a liquid
      management system, acting like a throttle to control the amount of vapour
      permitted to take that path. In short, with that geometry, composition of
      the vapour assumes more importance than relative apertures, and the diameter
      if the Liebig condenser tube has little effect. The description in the book
      was deliberately kept short as this was a new concept for still management
      and I didn't want to cloud the issue with long-winded technical
      explanations. With hindsight, perhaps I was wrong.
      I was looking @ Journeymans head, @ Homedistiller.org (Photos of
      Nixon-Stone style Stills),what is the advantage of having a second
      gate valve?.
      Journeyman came up with a neat variation of one of the initial test designs,
      where vapour flow was controlled by a gate valve in each of the two vapour
      paths. By fully opening up the product path valve and closing the reflux
      path valve, he can reduce imposed reflux to zero and operate his still like
      a simple reflux column, enabling stripping to continue to whatever stage he
      I will be using a number of brass fittings on my still,
      do I need to clean them as per 'Matt's Nixon-Stone Still', are these
      levels of lead significant?
      Opinions differ on whether the amount of lead leached from brass is
      significant. However, what must be said is that lead is a cumulative poison
      and should not be dismissed lightly. There has been some excellent advice
      recently on this List about treating brass to reduce the risk, no matter how
      small it might be, and it is well worth reading if this concerns you. An
      alternative method is to apply a thin electroplated coat of copper to any
      brass fittings that will carry liquid product. Note that brass inside the
      still, eg brass scrubbers, does not need treatment as any lead salts will
      end up in the boiler ... salts cannot be vaporised.
      My design has a number of brass flanges so that it can be broken
      down, can I use brass and copper brazing rods, to join the the copper
      pipes to the brass plates or must I use rods with a high silver
      content (expensive)?. I am having trouble obtaining a suitable needle
      valve, can I use one which is nickle plated copper?
      I use brass flanges too, and strongly recommend silver soldering is you want
      a strong joint as you would be working with slightly lower temperatures that
      if brazing with brass rod. When a brass component reaches the temperature
      at which brass brazing wires melt, then the whole piece tends to slump
      rapidly. It can be done, but it takes a lot of skill. If you can get away
      with a weaker joint, ordinary soldering is very much easier, and you don't
      need such a hot flame. Just don't use lead solder where it will be in
      contact with the final liquid product.

      All the best,
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