Bamboo flute care
Soon the summer will be upon us and it is amidst these seasonal extremes that I am asked by students: should I do something special to ensure my bamboo flutes don't crack?
There are tonnes of theories out there, but experience has taught me a couple things over the years about bamboo in the North American climate, and I thought I'd write these thoughts out in response to these questions.
I've often been asked whether I would recommend oiling bamboo flutes. Honestly, I've only done it once years ago when it was recommended to me; but, the thing is... those flutes, both mine and those of the person who recommended I oil them, all eventually saw cracks. So, what is oiling doing for the flute and why or why not to do it?
Essentially, bamboo is a wood. And as a wood, it carries within the fibre cells a certain volume of water from its days swaying in the breezes. This water wants to come to equilibrium with the humidity of the air around the flute, and when the humidity around the flute is less than that in the wood - the flute begins to dry or lose its water to the environment. When the humidity is equal or greater than that within the wood, there is either no change or a dampening of the wood.
These changes can occur gradually, and when they do, there is seldom a serious reaction as the wood gradually expands (as it dries) or contracts (as it becomes wet). The theory behind oiling wood is that a surface barrier is created that is water resistant, helping to keep water that is within the flute from escaping or vice versa.
In reality, however, my experience is that such modest protections, while effective in relatively minor humidity shifts at reducing the exchange of humidity - are in fact practically irrelevant in the kind of humidity shifts that tend to generate sudden and dangerous expansions or contractions of the wood fibres.
What types of conditions cause such shifts? ... Cars, cars and more cars.
Nothing in my recollection has been as frequently and directly related to cracks in bamboo flutes than leaving the instrument in a car. The rate at which a closed, un-airconditioned car accumulates heat and sees internal shifts in humidity is pretty hard to replicate in the normal day to day of carrying, storing or playing a bamboo flute. This environment is a death zone for bamboo, no matter what climate you are in, summer or winter. It's not simply that cars heat up a lot, it is the sheer speed at which the change occurs that seems to rapidly alter the humidity of the environment causing woods to lose or gain water faster than they're fibres are equipped to withstand.
Other student's and customers of mine have asked about lacquer and its role in protecting against cracks.
My answer to this is much the same. Lacquer can be applied to both the inside and outside surfaces of a bamboo flute. In theory, protecting the flute from absorbing water that accumulates on its surface. However, lacquer is not water proof; it is more or less water resistant. While this helps to protect particularly the interior of the flute from condensation of the breath, which forms water droplets than can soak into bare wood, it is still important to wipe away what water enters the flute frequently. Lacquer's secondary function in protecting against modest shifts in humidity, is that the hard surface it creates can act like a second skin, holding the bamboo in place and re-enforcing its bonds. It is not infallible, however, and any bamboo flute can crack regardless of what surface coating you have.
Maki bindings, which are often made of Ratan or sakura bark, are a fairly effective means of preventing cracks from either spreading or forming. Bound along areas of the body of the flute where they are not in the way of the player's fingers, these bindings apply a consistent bonding force from all sides toward the centre of the flute, effectively using force to negate any expansion of the wood body. They are quite decorative as well, and while they can cost to have applied professionally, they are one sure way to help prolong the life of your bamboo flute. Maki bindings, however, are also an organic plant mater and subject to the same expansion and contraction as bamboo when humidity shifts. You may find that a flute that looked quite sharp in Japan, finds itself with loose tangles of bindings if let to dry. The best remedy for this is either to have a professional or to attempt to re-bind the flute to the tightness you require. Ratan tightened in Japan will loosen in North America and thus if you rebind the Ratan when it has come loose here in your local climate, it is much more likely to hold firm and perform its function. This process can involve detaching the lower end of the binding delicately, and unbinding the strip until a point that it can be pulled tightly and rebound. Shaving the loose end and using a firm wood or quick drying adhesive to neatly tuck the loose end away.