Re: Oiling winds

[Dana S Emery <emery@onyx.si.edu>]

Recorders and flutes (at least) are quite sensitive to the smoothness of
the bore. Turbulence introduced by the way a fingerhole merges with the
bore is one issue; most wooden instruments of quality feature "undercut"
holes which reduce that turbulence.  Another issue is the fuzzyness that
raised grain can introduce.  The warm breath of the player contains
moisture: as it cools off in the upper part of the instrument that moisture
transfers to the wood, wetting and raising the grain.  Eventually (typ an
hour of constant play) it alters the shape of a recorder windway enough to
affect the sound, at which point a player will usually rest the instrument
till it dries out.  Smaller instruments may even get enough moisture into
their upper parts that they go ovoid temporarily, causing them to alter
pitch (l/bore-area ratio determines pitch).

Pipes will be less affected by this as the players breath has some time to
cool off (especially in cooler weather), but some condensation in the bag
itself is inevitable, and I am aware that the leather of the bag gets
considerable attention in the way of oil in order to combat the effects of
that moisture.  Im not sure if pipers have problems similar to brass
players with accumulated moisture.

As we all know, moisture gradients induce stress in wood, and stress is bad
for stability, so oil which inhibits this wetting may be beneficial in the
long run.  However, it may also be harmful in the short run, the shed
moisture will itself affect the acoustics of the instrument (consider brass
intsruments and their spit-valves).  Players are encouraged to play "dry",
with varying degrees of success (I tend to be a wet player).

The process of boreing and reaming a woodwind leaves small disturbed wood
fibers all over the surface of the bore.  Some manufacturors attempt to
clean these up, but this is a delicate process, an excess of zeal can alter
the bore shape enough to render the instrument untunable over its desired
range.  The physical action of swabing the instrument removes some of the
fuzz over time, a polymerizing oil will prevent subsequent formation of
more fuzz from moisture being unable to "raise grain".

Note, there are parts of a recorder (the windway) which must remain
hygroscopic and are _never_ finished in any way, I suspect the head joint
and cork of a flute may be similar, but am not as familiar with that
instrument.

--
Dana S. Emery
Smithsonian Institution
Laboratory of Molecular Systematics
MRC-534, MSC A2000
Washington DC 20560

(301) 238-3444     (voice)
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