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Re: Water vs vapour

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  • tw45ph
    ... 31mm OD and ... rubber bung ... the ... poured ... Hardly - ... was ... tube to one ... really ... scale ... steam ... barrier would ... temperatures ...
    Message 1 of 4 , Jun 1, 2004
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      --- In earlyflute@yahoogroups.com, Terry McGee <terry@m...> wrote:
      > OK, next exciting installment....
      >
      > I took a blackwood head blank - a cylinder 170mm long, 19mm ID,
      31mm OD and
      > polished its bore to a good shine. It weighed 102.5gm. Put a
      rubber bung
      > in one end, filled it with cold water and stood it on end for 3
      > hours. Poured out the water, removed the bung, dried and weighed
      the
      > blank. It appeared to lose weight - now 101 gms! The water that
      poured
      > out was a little brown - could there be a gram of dust in it?
      Hardly -
      > that's 1% of the weight of the piece! Most interestingly, the bore
      was
      > still shiny.
      >
      > Hooked it up to a source of steam (pressure cooker plus plastic
      tube to one
      > end). After:
      >
      > 1 min - polish fogged, 100gm
      > 5 min - quite fogged, 100gm
      > 10 min - no longer perfectly smooth to touch, 100.5gm
      > 20 min - grain lines becoming visible in bore 101.5gm
      > 30 min - grain lines more visible, bore less smooth to touch, 101gm.
      >
      > The weighing device is an electronic 2Kg kitchen scale and hasn't
      really
      > enough resolution for the task. But it tells us that no large-
      scale
      > absorption of water took place.
      >
      > I think the effect on the bore polish tells us more. 1 minute of
      steam
      > produced visible fogging while 3 hours under water didn't.
      >
      > So it would appear that any serious test of timber or vapour
      barrier would
      > need to involve vapour, not water. Probably not at steam
      temperatures
      > though as that might soften some barriers. Steaming might prove a
      > convenient way to raise the grain artificially before final
      polishing, but
      > care would need to be taken not to induce too much stress in the
      timber.
      >
      > The blank became uncomfortably hot to handle (on the outside) after
      about 5
      > minutes. The end grain at both ends of the piece showed sparkling
      dots
      > where resin had extruded from the resin ducts, and tiny fissures of
      end
      > checking (visible only under the microscope). No checking was
      noted on the
      > outside. It is possible therefore that weight gain due to moisture
      intake
      > was offset by weight loss due to moisture and resin loss from the
      ends.
      >
      > About 50mL of water condensed in the head (and was collected in a
      container
      > below) over the thirty minutes and was of a brownish colour.
      >
      > Terry
      >
      >
      > Terry McGee
      >
      > 61 Calder Crescent, Holder ACT 2611 Australia
      > Phone +61 (0)2 6288 8006, Fax +61 (0)2 6287 4263
      > mailto: terry@m...
      > http://www.mcgee-flutes.com
      >
      > - wooden flutes for Irish and classical music
      > - wooden flute research, restorations and repairs
      > - maintenance, National Carillon.
      >
      > ----------
      > Assisted by the Commonwealth Government through the Australia
      Council, its
      > arts funding and advisory body, and by the ACT Government through
      its
      > Cultural Council.



      It is known to take some considerable time for water to get into
      wood. The rough rule of thumb is that it takes a whole day at least
      for the moisture content of a piece of wood to catch up with an
      atmospheric humidity change.

      What then of frequently seen missives to the effect that it is
      dangerous to play an instrument for an hour while ten minutes is
      safe?

      You also need to assess whatever else may have penetrated the wood.

      Occassionally I boil a recorder to get rid of impregnated parafin
      wax, except that it is all but impossible to get rid of it all. The
      stuff is a nuisance when wanting to friction polish to renovate a
      rough item. When the wood warms up it is amazing to see how much of
      the wax will ooze out again. The sound of an instrument will also
      change as a result but that's another subject. More than half of the
      volume of an ordinary sample of maple is void space. It may not then
      be possible to impregnate more than 80 per cent of the void but
      whatever does get in is bound to make a difference.

      Boiling water is also handy as a first aid treatment for loose
      fitting cork joints. With only five seconds or so in the steam the
      cork swells up. Old cork will shrink again afterwards but it is
      possible to work some glue into the swollen cork to keep it puffed up.

      ------------
      The Old Grey Whistle Tester, London, UK
    • mailfrom.earlyflute.20.glauber@spamgourm
      ... I wonder if you should have sealed the ends with superglue or something similar. g
      Message 2 of 4 , Jun 1, 2004
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        --- In earlyflute@yahoogroups.com, Terry McGee <terry@m...> wrote:
        > OK, next exciting installment....
        > [...]
        > It is possible therefore that weight gain due to moisture intake
        > was offset by weight loss due to moisture and resin loss from the
        > ends.

        I wonder if you should have sealed the ends with superglue or
        something similar.

        g
      • Terry McGee
        ... Heh heh, then it s called a bomb! Terry Terry McGee 61 Calder Crescent, Holder ACT 2611 Australia Phone +61 (0)2 6288 8006, Fax +61 (0)2 6287 4263 mailto:
        Message 3 of 4 , Jun 1, 2004
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          At 01:09 AM 2/06/2004, you wrote:

          I wonder if you should have sealed the ends with superglue or
          something similar.

          Heh heh, then it's called a bomb!

          Terry

                            Terry McGee

                   61 Calder Crescent, Holder ACT 2611 Australia
                    Phone +61 (0)2 6288 8006, Fax +61 (0)2 6287 4263       
                   mailto: terry@...                   
                  http://www.mcgee-flutes.com

                    - wooden flutes for Irish and classical music
                   - wooden flute research, restorations and repairs
                    - maintenance, National Carillon.


          Assisted by the Commonwealth Government through the Australia Council, its arts funding and advisory body, and by the ACT Government through its Cultural Council.

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