Maintaining Your Instrument
Please note that you should contact the manufacturer of your instrument for specific
care instructions. Should you choose to implement any care procedure found on this
page, you do so completely at your own risk. Some of the procedures on this page are
experimental or theoretical.
It is generally recommended that you oil a wooden flute as part of its normal
maintenance. Selecting the type of oil to use has been a hot topic for conversation,
with various instrument makers and players adopting positions for or against various oils.
Kevin Krell submitted a link to an article by Raymond and Lee Dessy about the
chemistry behind oiling
woodwind instruments (from a site which focuses on recorders maintained by
Nicholas S. Lander).
Also, here is an excellent overview of
available oils that was contributed to the woodenflute email list by M. Dominic Ryan <email@example.com>:
Some time ago I inquired amongst several people as to the best oil for my flute.
The one loud concensus is *not* to use boiled linseed oil. Beyond that there
were various suggestions to use almond oil, raw linseed oil, and olive oil.
I happen to be a chemist and an occasional woodworker, though definitly not a hallowed
flute-make. Nonetheless, from a finishing point of view I am now less enthusiastic about
olive oil. What follows is an explantion of what I have learned so far. Warning, some
chemistry is included, so if you already rolling your eyes, delete now. It is also a bit
long. Nor am I the first person to post on this, so while I no longer have the names of
those that preceded my post, my thanks to them for piquing my interest and providing some
of the background below as well..
All the oils are essentially triglycerides, that is a fatty acid ester of glycerol. (If
that doesn't mean anything to you hold on...) But there is quite a variation in what else
is in there and in just what specific fatty acid is present. There are different ones and
they have different properties. If the molecular structure is right the fatty acid will
polymerize by forming chemical bonds between individual molecules of fatty
acid (crosslinking them together). This results in a hard polymer. The same chemical
element that can cross link can also be oxidized by atomspheric oxygen. Vegetable oils,
such as olive oil, corn oil, peanut oil (despite the nut name it appears to behave like a
vegetable oil), all have a much greater susceptibility to oxidation. They also are
essentially completely non-hardening, or only so slowly that one can find roman era
hardened oil, but not within a couple of years.
All the oils will soak into the wood and provide protection against water by coating
the fibers with a protective layer that slows down, but does not completely prevent, water
from crossing into the cells of the plant materiel. The cells swell up, and the wood
Once the oil has polymerized the rate of water crossing is significantly reduced and
the oil is more permanently retained. Without crosslinking the oil is greatly more subject
to mechanical removal. This includes rubbing, but *also* just the passing of moisture
across the surface. Some oil is entrained, slowly, from truly non-hardening oil.
Mineral oils are quite different again. There is essentially no mechanism for air
oxidation of mineral oil (at room temperature, 500 degrees is another matter). Nor is
there a possibility to crosslink. They have a very different chemical structure and are
called hydrocarbons. Hydrocarbons derive differences in physical properties by having a
different length of molecular chain. Volatile ones are short chains, i.e. gasoline to
kerosene, and non-volatile ones are long, i.e. mineral oil to engine oil to tar.
The vegetable/nut oils have different properties not so much because of different
*lengths* of molecular structure, but because of different chemical bonding patterns of
molecules that are very nearly the same length. The lack of a route to oxidation makes
mineral oils very stable, but non-digestible by humans, and even toxic.
Thus it seems that olive oil will protect from moisture to an extent, but it will
require quite frequent reapplication. I may also possibly suffer from oxidation to produce
rancid oil components but that has not apparently been a problem people have talked about.
I suspect that it is because the "rancid" component of oxidised vegetable oils
is somewhat more volatile and never noticed since there is only a small amount of oil in
the wood anyway. But, it is perhaps an additional route to loss of oil over time.
The nut-oils, which includes seed oils, are naturally prone to polymerization over
time. This is why they protect more. The hardening seems to take months to finish. This
gives a chance to have a very thin and well distrubuted coating. However, in the furniture
industry there is no time to do this and chemical polymerization agents are added to speed
up the polymerizing process. These are usually toxic. Some of that happens naturally upon
boiling the oil. The end result is that the oil will harden *MUCH* faster. In the case of
linseed oil, boiled linseed oil hardens faster, but incompletely except over a very long
time as well. It tends to get gummy because of the nature of the crosslinked structure.
So, "dryers" are added to crosslink more completely the oils. I suspect
that if it were not for wanting to put your lips on the finish for long periods at shot a
hardened wood finish might be ok. But there would be the additional difficulty of getting
at the inner surfaces to rub them down as part of the finishing process for that sort of
Even a well hardened oil will not provide a complete barrier. To do that would require
one of a few possible finishes that completely envelop the wood. Poylurethane will do that
and so will acrylic, but polyurethane can be applied in quite thin layers which is what is
needed for good curing and hardening. Any flute makers willing to take a flyer on a
polyurethane coating? If done well it might even be stable in Winnepeg at 7% humidity. I
think you would have to immerse the flute and then perhaps gently spin it on a string to
force off the excess. I would estimate that about 5 layers might provide a good water
proofing. I would also use extra hardening agent in the urethane. One could use the newer
non-solvent urethane finishes.
Lastly, I would really love to be corrected on any of this I may have misunderstood if
it contradicts what your experiences are. I am trying to put this into a chemical context.
References to additional information would be ideal.
Here is an extract from a response to Dominic's email sent by Terry McGee:
I tried polyurethane a long time ago (plain old commercial goop) and found it
ineffectual. I got better results from Watco Danish Oil (2 coats) but not good enough. The
commercial bore oil is much better than either of these or vegetable oil.
It is generally agreed that changes in humidity and/or temperature are potential causes
for cracks in wooden flutes. Rod Cameron <firstname.lastname@example.org>
contributed the following email message to the earlyflute email list:
I would think that one of the worst things you could do to a wooden flute is put a
humidifier inside the bore. Flutes crack generally as a result of moisture being
introduced too quickly into the bore of the flute by the player's breath while the outside
of the instrument remains relatively dry, or very dry in the case of low humidity winters.
The cracking is the result of the inside wanting to expand because it is moist, and the
outside wanting to stay the same. This produces what is called a 'hoop stress'. Ideally
what we want is a condition whereby the moisture can rapidly and evenly permeate
throughout the cross-section of the wooden tube so that the whole body expands at the same
rate and hence no hoop stress is set up. Once the flute is 'waterlogged', so to speak, it
should be better able to handle long playing sessions. This is why makers recommend a
careful playing in period of say...10 minutes a day morning and afternoon, increasing by
five minutes each day. This allows more time for the injections of moisture from the
player's breath in the bore to permeate out throughout the cross-section to an even
result. In dry weather conditions, a flute left around the room while it is not played
will rapidly lose ground in this process.
I recommend humidifiers on the outside of the flute, not the inside. I do not see any
need to buy special cello humidifiers, etc., when all you are getting is something that
holds a little moisture. For dry conditions, put your flute back into its soft case and
put the soft case into a plastic bag within which is a small, damp cloth. This ensures
that the flute lives its life in a controlled reasonably humid environment. The precious
moisture added in small doses by sticking to the 'play in' schedule does not then
evaporate but instead permeates evenly until a state of 'waterlogged' flute results. By
all means swab the flute out after playing, otherwise the wood will think it is still
being played in a long session as it sits in its case trying to absorb the droplets
clinging to the bore. I know that it seems undignified to think about the wood flute as
needing to be waterlogged, but that is the case with a fully played-in flute....what do
you think is happening to all of that moisture from your breath? You will know that you
are overdoing the damp cloth routine if you end up with a mold in the bore, so a little
goes a long way. Those wanting to know more may put a small humidity meter in the plastic
bag. Those who are even more curious will weigh their flute when it is new and dry and
graph the increase in weight until it is 'played in'...noting that weight. In my
experience, quite a few professional players crack their flutes by picking up a flute that
has been idle for some time and then going to a long rehearsal session on the assumption
that the flute is not new, has been played lots in the past, and so must be in a constant
played-in condition. Wrong. Flutes loose their moisture quite fast...again a daily
weighing will reveal this. If you absolutely have to play a long session on a dry flute no
matter what the risk, it might be worth sponging it down on the outside regularly as you
play....not the best treatment for the wood surface, but it allows moisture to enter from
the outside as it enters on the inside from playing, and to a degree this lowers the hoop
stress. If you already know the weight of your flute when it is in a thoroughly played-in
state, then simply putting it on the weigh scale will tell you how dry it has become, and
hence whether you need to again go slowly.
Almost everyone who cracks a flute wants to put the blame on a faulty piece of wood.
However flutes can be subjected, wittingly and unwittingly, to fast changes of humidity
and temperature with serious results.
In the particular case of later flutes with metal lined headjoints, this is almost an
accident waiting to happen as the metal bore will not yield inwards if and when the wooden
body wants to shrink around it due to experiencing dryness. I would be inclined to roll
the metal lined headjoint in a very slightly dampened cloth during dangerously dry winter
months. Remember also that in olden times flutes did not travel faster than a walking
horse, and now many expect to play today in London and tomorrow in dry Madrid, even after
the punishing low pressure journey on an aircraft.
Please do not regard the above paragraphs as gospel, and do not come back at me saying
you followed my instructions and your flute cracked. I put these points forward only as
talking points, and toss them out as lures over the still, early morning waters of the
chat line, inviting you to rise to the fly and correct me where my thinking is faulty. I
would be cautious about following any one person's advice, including my own, without first
finding out if others with experience agree.