ow that you've made your harvest it's time to store and prepare the bamboo for future use. If you have no plans of using the bamboo in the near future it can be simply put away and left to dry out naturally.
It's better to store it vertically rather than lay it horizontally. It dries out more evenly and quickly this way. I just stand it up against a wall in my garage on the concrete floor. If you don't have a concrete floor then it's important to not have the ends of the bamboo in contact with the earth.
The room where the bamboo is stored needs to be quite dry with plenty of air circulation. When the bamboo is first cut it contains a lot of moisture and if the storage area is damp there is a strong possibly that it will get mouldy which not only discolours the bamboo but also affects its strength.
That's all you need to do. This way the bamboo will last for many years and at any time you can chose a piece and start to make a flute.
Rather than just store the bamboo in one piece as described above I usually cut it to approximate lengths straight after harvesting. I decide on the types of flutes I wish to make from a particular piece and then cut it accordingly a node or two longer than the final flute will be.
In this way the bamboo will dry out far more quickly than if it is left in one piece. I still stand it vertically to dry. However because the pieces are smaller it is easy make simple drying stands. As with storing the bamboo in one piece this way the bamboo will also last for many years.
Preparing the Bamboo
Preparing the bamboo for flute making is quite an involved process. There are a few stages which I'll describe as follows.
Cutting the bamboo to approximate lengths
Rather than just store the bamboo in whole pieces as described in the previous section I usually cut it to approximate lengths straight after harvesting. That way the bamboo dries out much faster and I get a better idea of the quality since I can see the wall thickness at a few places
Once cut like this I sort it out depending on the type of flutes I wish to make. As mentioned before you can make 2 to 3 flutes out of a single culm. From experience I know how long a particular flute needs to be for a certain key. A deeper sounding flute is longer than a higher pitched one. When I cut the bamboo to approximate lengths I cut it a node or two longer than the finished product will be. This allows for some flexibility in the final length and key of the flute.
For example say I cut a piece of bamboo and anticipate it will make a really good flute in the key of C. I cut it then to length that will allow me to make a flute in lower keys of B or A. When I get around to using the piece I can then always cut it shorter if I find the bamboo is not suitable for a lower pitched flute.
Once the bamboo is cut to approximate lengths I then sort it out according the to the key and quality of flute I intend to make. A piece of bamboo varies in consistency from the bottom to the top. The root section is much denser and has a greater wall thickness than the top. I basically make three qualities of flutes, high, medium and low.
Generally speaking the root section will make a high quality flute. The mid section will make a medium quality and the top section will make a low quality flute. So I sort it out this way. I put all the root sections together. All the mid sections together and so on for the top sections.
Curing the bamboo
After having sorted the bamboo it then needs to be "cured". Curing the bamboo is just drying it out for use as you cannot use it while it contains moisture. For the sake of this discussion I'll describe how I cure the top and middle sections of the bamboo as the process for these is the same. I use a slightly different process to cure the root section. This will be detailed in a later section on how to make high quality flutes using the root section.
Again if you're not in a hurry to make flutes you can just store the bamboo after it has been cut into sections, stand it vertically and let it dry out naturally. This works fine provided you've harvested good quality bamboo. Good quality bamboo is taken to mean as being very dense with thick walls. The running species of bamboo I've described is usually of very high quality depending on how it is grown and the climatic conditions. If left to dry naturally there will be minimal shrinkage.
You should note that If the bamboo is left to dry out like this it will take around at least 6 months or so before it is usable. And even after this time it will need to be followed up with some sort of final heat treatment because it will still contain a considerable amount of moisture.
There is another way of curing the bamboo however. This is the what I call the "burn cure method". With this method you can use the bamboo within a few of days of harvesting. Also after burn curing the bamboo is much stronger than the natural drying method. Burn curing makes the bamboo virtually indestructible by actually changing it's molecular structure as well as giving it an incredibly durable and fantastic looking finish. A flute made from a burn cured piece of bamboo will last forever in any climate if looked after.
I have flutes that are 15 year old and have been exposed to climates varying from extreme tropical to snow and ice. They are intact showing absolutely no signs of cracking and look as new as the day they were made. Needless to say I highly recommend this method of curing.
The burn cure method
This consists of heating the green bamboo to the right amount with a gas blowtorch. You can buy these in any hardware store. Just get yourself a gas bottle and blowtorch and you're away. The blowtorches usually come with different nozzles varying from course to fine.
I'll describe the burn cure method here but be aware that it might take you a little time to get confident with this technique so I advise starting off with pieces of scrap bamboo till you get the feel.
The best way to burn cure the bamboo is take a piece which you've cut to approximate length, hold it on one end as shown in the diagram and start to burn from the other.
If you've recently cut the bamboo it will be quite green to look at. Light the torch and start to burn the piece at one end moving the flame around and back and forth so as not to over burn the piece. It is best to start with a fairly gentle flame until you get the hang of it. When you're proficient with the method you can increase the intensity of the flame.
When you start to burn you'll notice that the bamboo will lose its green colour and turn orange brown in colour. The surface will also start to bubble. This bubbling is the resin inside the bamboo coming to the surface. If you touch this resin it is very sticky almost like a heavy duty varnish. In fact it is like a varnish and when dry almost totally waterproof.
During this burning process always keep moving the flame and rotate the bamboo so as to burn it all around the outside. Burn only a couple of sections at a time. That is do not burn the whole piece in one go. Only burn a couple of sections between nodes at a time. This is because the resin that extrudes from the bamboo dries fairly quickly.
What you want to do is burn a few sections then with a clean cloth wipe the burnt sections. This has the effect of spreading the resin evenly over the surface. After you spread the resin over the bamboo it will then dry to a high gloss like finish and the bamboo will be a yellow like colour.
So burn a few sections, spread the resin then burn a few more and again spread the resin over those sections and so on until the whole piece has been treated this way.
If you burn the whole piece in one go and then try to spread the resin with the cloth you'll find the resin has already started to cool and dry and be very difficult to spread. So you need to spread it while it's very hot. This way it's very liquid and easy to spread.
You'll also notice that during the burning process an enormous amount of moisture is released from the ends of the bamboo. It's literally pours out the ends. Be very careful while you're burning not to touch the ends as it is super hot and will likely scald you.
With little bit of practice you'll get quite good at burning. It should only take you a about 5 or so minutes to burn one piece. After you master the basic technique you can then start to experiment with being creative in the burning process. You'll find that beautiful patterns of all sorts can be burnt in the bamboo if you slightly over burn some sections.
Burning the bamboo then in this way actually serves a few purposes. These are:
After the piece has been burnt like this put it aside to cool down. Stand it vertically so as not to damage the beautiful finished surface.
After about 15 minutes or so the piece will be cool enough to handle. The resin on the surface will have also dried. At this stage of the process I pierce the inner nodal membranes inside the bore with a sharp rod. You can use almost anything for this. The idea here is not to completely remove the entire membrane from the inside of the node. Just put a whole through big enough so that air can freely circulate throughout the inside of the whole piece.
Leave it like this for a couple of days to a week in a warm dry place and presto. The bamboo is ready for flute making.
s with all art forms there are an endless number of ways to do things. The best is to find what suits you. I have found that when preparing and curing the bamboo it's more efficient to work in a batch type process. That is do many of the same operations at the same time rather than complete each piece individually.
For example say you have 20 pieces of bamboo that you've just harvested. The preparing and curing process would be as follows.
So from time of harvest to when the bamboo is ready for flute making can be as short as 3 or 4 days. Certainly quicker than waiting a year or so for it to dry naturally!
Even if you left it to dry naturally you'd find the end product would not be as strong as if it is burned. After the bamboo has been left to dry naturally it can still be burned. However most of the resin dissipates while drying. So if you want to burn the bamboo after it has been drying naturally for a while you have to be much gentler with the burning process otherwise you can easily char the surface.
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