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Notes on Maintenance


A delrin flute is not subject to cracking due to changes in humidity
and temperature and does not need as much care or attention as a
wooden flute does.

There is a small pot of grease included with each flute for greasing
the threaded tenons and the metal tuning slide.

Vaseline can also be used for the threads – though some brands of
vaseline can be a little too thin. The metal slide needs a thicker grease than
vaseline.The grease supplied in the pot is made from beeswax and
vaseline by simply melting the two together in a microwave oven and
adjusting the relative quantities until the required consistency
is obtained. A ratio of about 50/50 of vaseline to beeswax is a usually a
good mix to start from.

The joint tenons are threaded with waxed thread which is the
traditional manner of sealing joints on woodwind instruments and is
the easiest for the player to maintain. The thread used is the
commonly available thin polyester sewing thread.  For those with
experience of wooden flutes and recorders, joints on a delrin flute do
not swell and contract with changes of humidity and temperature.

However, it is generally better to prefer the polyester thread over a
cotton thread as the cotton can swell when wet if the joint is not
waxed or greased properly and the joint could  then become difficult
to separate – but even then there would be no risk of cracking the
delrin. The tenons should be greased regularly as this helps to keep
them from leaking air as well as allowing them to be joined and taken
apart easily. Of course they should be kept free of grit.

If a joint becomes too loose, it may be necessary to add some thread
by winding it on to the tenon. Conversely, if a joint becomes too
tight even after greasing, it will only be necessary to remove a
little of the thread. New thread should always be carefully greased.
The end of the thread has been left loose and you only need to run a
fingernail across the threads to find it.

Note that the metal tuning slide on my flutes must be kept greased as
is usually the case with the slides on 19th century flutes. If the
slide is not greased it will leak air and the performance of the flute
will suffer. This is different to the slide on the modern silver flute
which should never be greased.

You should only need to grease the slide if it starts to become either
too stiff or too loose. About once or twice a year should be enough.
To grease the slide, simply separate the head
from the barrel section and use a clean cloth to clean off the old
grease from both metal tubes. Then rub a little grease on the outside
of the inner tube and also on the inside of the outer tube. Test the
fit. If it is slightly loose, add more grease. If it feels a little
tight, take off some of the grease. The slide needs a thicker,
stiffer grease than vaseline. Finally, be sure to clean off the grease
which has squeezed out of the end of the two slide tubes inside the barrel.

Make sure that grease does not build up inside the bore of the slide
and also make sure no grit or dust gets in the tuning slide as it can
cause scratches and these will in turn cause air leaks.

The head and barrel should always be kept joined together as this
prevents grit from getting into the slide.

If your flute comes with a white delrin stopper in the headjoint, it
will have a rubber O-ring in a groove on the outside. If you remove
the stopper for some reason, you should wipe a touch of grease on the
outside of the O-ring and also a little in the bore where it sits
before replacing it. If you put too much grease on, the stopper will
slide too easily and you will need to take off some of the grease.
There is also a rubber O-ring on the endcap which needs greasing

If the delrin stopper needs to be moved, this should be done with a wooden
dowel with a large enough diameter so the stopper won't get marked - 14mm
to 18mm will do. Make a mark at 20mm from one end and use that to reposition
the stopper correctly in the head.

If the flute has a cork stopper, the outside should also be lightly
greased if it is removed.


The stopper should never move too easily as it is essential that it
remain in its correct position.

Note that it is extremely important to position the stopper or cork
reflector correctly in the bore when replacing it.

The flute will not work properly if this is not done right.

Here are the correct positions for the reflector (the stopper or cork)
in the head-joint on my flutes - this can vary for different makers:

Pratten and Rudall & Rose types – 20mm from the centre of the embouchure hole.

Boehm bore type – 17mm from the centre of the embouchure hole.

The cork in the headjoint of the aluminium flute with delrin head does
not have a hard facing and if it needs to be moved, this should be done
with a wooden dowel which has a large enough diameter - around 14mm to 16mm diameter
will do. Make a mark at 17mm from one end of the dowel and use this to
reposition the cork correctly. The standard metal cleaning rod used
for Boehm flutes is too thin and can easily damage the cork facing.

If you ever do use a cleaning stick designed for a Boehm flute on a
conical flute, you need to remember not to use the mark at 17mm to set the
stopper position.

Occasionally the surface of the delrin body will become a dry, greyish
colour. When this happens, just rub a little of the grease or vaseline
on the exterior and then wipe off all excess until “dry” and this will
restore the original dark appearance. The same can be done with the
bore using a cloth on the cleaning stick. It is important to make sure
afterwards that there are no accumulations of grease
in the embouchure hole or toneholes.

The embouchure hole and toneholes should be inspected regularly and
can be cleaned out with cotton buds.

As with any musical instrument, it is not a good idea to leave the
flute in a car on a hot day.