|
|
What the harpsichordist needs to know about quill plectra
These notes are intended to provide information about the basic facts of bird quill when used as a plectrum in harpsichords and
describe effective preventive maintainance for an even touch.
Correction strategies for "hardened" quills are also described.
There are several new findings which are published here. These
results are based on extensive testing, which has been reported at my website
here.
What happens to bird quill when used in a harpsichord?
Bird quill will not "work harden" with age (as does Delrin). The
touch may become slightly lighter after extensive use, e.g. after
6 months, as the tip becomes polished.
As is well known, the touch with untreated bird quill often
suddenly becomes harder (within 50-700 plucks). Measured with a
calbrated voicing weight on the key, the weight will be about 25
mm nearer the player. This is the result of the top surface
becoming rougher and creating more resistance to the string
sliding along it. The quill material itself has not become
"harder", or "stiffer", or dried out. However the pluck can be
said to be harder or stiffer since more force is required to
effect a pluck. Colloquially one may speak of the quill becoming
"harder", by which one means the touch becoming harder
A cause of accelerated wear: the string
New harpsichord strings will cause an accelerated abrasion of the
quill plectrum, i.e. hardening of the pluck occurs within 50-700
plucks. Played strings eventually become smoother and cause much
less wear. With a polished string, even after 2000 plucks no wear
may be found on an untreated quill. (e.g. Goldberg Variation 1
played with repeats 50 times, i.e. 100 minutes playing = 2000
plucks for g1)
A successful maintainance strategy to reduce wear
The top surface of a new quill absorbs virtually no oil, whereas
the underside readily absorbs it.
If bird quill is liberally oiled only on the underside with
Ballistol and left to soak in for 45 minutes it will be found
that the plectrum is considerably more resistant to wear. Even
on a new string, after oiling with Ballistol, no wear was
observed after 2000 plucks. For example, this strategy has
prevented any plectra giving a hard touch in a 3-register
harpsichord during the first 6 months.
Oiling only the underside also has the effect of significantly reducing wear of the quill.
If a bird quill is repeatedly oiled on the underside until
saturation results (i.e. oiled two times over a period of hours)
then the quill becomes slightly stiffer (the voicing weight on
the key moved 3-6 mm towards the player). This amount of oil in
the quill is not required for the benefits of oiling to become
apparent. The effects of excessive oiling will eventually be
dissipated by playing although this may require 1000 plucks.
Since oiling the underside is more considerably more effective
than oiling the top surface, only the underside need be oiled as
a maintainance procedure.
Oiling the top surface provides a small amount of lubrication
which partially removes the advantageous sense of plucking the
string, which one has with bird quill, but not with Delrin. This
is a further reason to avoid oiling the top surface.
Correcting a "hardened" quill
If an untreated bird quill which gives a hard pluck is liberally
oiled on the underside with Ballistol and left to soak in for 45
minutes, it will be found that the plectrum may have regained
fully its prior plucking strength.
When the pluck of a quill has become hard, rubbing the tip of the
quill (where it touches the string) with the edge of a finger
nail (as recommended by Tilman Skowroneck), or polishing it with
the stem of a bird quill ten times will often restore the
original plucking strength. However this effect will usually only
last a short time, perhaps 10-30 plucks, although it might hold
for considerably longer. Nevertheless, this may be a useful
correction method when immediate results are required, e.g.
before or during a concert. This polishing procedure requires a
special block to support the quill, a voicing block is almost as
good, although it lacks the upward slope; in an emergency use
your thumbnail.
Applying skin grease or oil only to the top surface of a bird
quill after the pluck has become hard, produces a slight
immediate lightening of the touch, but further playing is
required in order to reduce the excessive plucking strength. This
may not fully restore the prior plucking strength, even after 200
plucks. However, skin grease appears to be a little quicker than
oil in restoring a usable playing strength, in perhaps 100 plucks.
In some situations the harpsichordist may not have the time or
resources to do anything but rub the tip of the plectrum, apply
skin grease, and carry on playing.
Less successful maintainance strategies
Oiling the top surface of a quill is only moderately effective
in preventing the touch of a quill becoming too hard during the
initial period of use with a new string. The plectrum remained
playable, although some hardening was evident, e.g. a 5-10 mm
difference of the voicing weight position, equivalent to a
noticeable difference in voicing strength. However, the type of
oil determines the result and it must be applied often. Vogel's
Kielöl [quill oil] and Ballistol were found to be the most effective. Emu oil
and grease from one's skin were less effective. Olive oil was
ineffective in preventing the touch hardening.
Wear of the quill is more pronounced when only the top surface is oiled.
Quills which have been oiled only on the top surface show a
"stiffening effect": after leaving the instrument to rest for a
few hours the touch of quills can become slightly harder (typically + 8 mm). This
effect disappears after a "waking up" period of being played a
few times.
Suitable oils
Oil for bird quill should be non-drying, not be subject to
biological degradation, not become acidic, and preferably have
a long shelf life. Thus, olive oil is not recommended because it
may become sticky and hinder the return of the plectrum. Some
vegetable oils (almond oil, Vogel's Kielöl) are probably non-
drying, but subject to degradation bacterially or with time, as
is Emu oil (animal origin). Ballistol (a high grade paraffin oil)
qualifies on all counts and is cheaper than most alternatives.
Ballistol is readily available in shops selling sporting guns,
but can be obtained online from: http://www.conrad.de
Other undesirable effects in bird quill
A "creaking" noise of the string on the tip of the quill just
before plucking is due to major irregularities of the surface and
is usually unavoidable. Creaking is not necessarily accompanied
by an excessive plucking strength.
Quills from swan feathers showed no substantial variation in
touch with changes in humidity. A rise in temperature gave a
slight decrease of plucking strength in 1 in 20 of the quills
tested. Swan quills can be considered reliable, turkey quills
have a poorer reputation.
Recommended routine maintainance procedure
1. Three to four times in the first year (i.e. with new strings, two
times in the second year): Oil liberally only the underside of
the quill: a thick film should be visible. Ballistol is known to
work and is recommended as non-drying with a virtually indefinite
shelf life. A small piece of wire, e.g. straighten out a wire
paper clip, (circa 0.8 mm diameter), a toothpick, or a small
brush (no.2 watercolour) can be used to apply oil.
2. Place the jack on a horizontal surface with the quill facing
down to prevent oil runing into the tongue and leave for at least
45 minutes, after which time the quill will appear translucent.
Leaving the quill longer will not improve the result, but is
permissable. Oiling the quill a second time will increase the
plucking strength slightly and is unnecessary for the
effectiveness of this method.
3. Wipe off any excess oil with tissue paper or a cotton bud.
What to do if the quill touch hardens
1. Know that the surface of the quill has become slightly
rougher.
2. Oil the underside and (if possible) leave for 45 minutes.
3. If you cannot wait (or step 2 was ineffective), polish the tip
of the quill x10. If no improvement has taken place, regard the
new state of roughness as permanent and re-voice. If there is no
time to re-voice, apply skin grease, quickly play 20-50 times
then continue playing. When time permits try stage 2.
4. If several quills "harden" at about the same time it is probably an indication that
all quills require oiling.
Reference: Tilman Skowroneck. Harpsichord Voicing:
http://skowroneck.wordpress.com/2008/03/08/voicing-complete-pdf/
page updated 4 June 2012
[HOME] [TOP OF PAGE] [SITE MAP]
|