Step 1: Choose You Bamboo
First thing you need to do is to choose the piece of bamboo you want to use. I sugest one that has a very straight and prefferably a very flat side to it around the node. The node is where two sections of bamboo meet at.
The piece I chose has been dried already. I do not suggest using a piece of green bamboo for this project. As it dries, it has a higher tendency to split or warp slightly which will change the tone and sound of the bamboo greatly.
Step 2: Cut Your Bamboo
When you cut this bamboo, you want to cut about an inch above the node you will be using, and several inches below it as well. This should give you a piece of bamboo that's just about the length of your hand (fits in pocket). If the bamboo still has branches and leaves they should be cut as close to the body as possible and sanded down flush, as in the picture.
Step 3: Clean Out the Bamboo.
Using another piece of bamboo as a sort of bottle brush, clean out the layer of white from the inside of bamboo. Be vigorous to get all of this lining out as it will help to prevent molding and will help air flow later on in the project. Be sure to do both ends of bamboo, and be carefull not to knock the node out or poke a hole in it by accident.
Step 4: Finding Your "bird"
The next part of the guide is a little tricky. You need to now find a piece of bamboo that has an inner diameter that is as close to the outer diamter of the top of your bamboo as possible. Check for inner diameter AFTER cleaning, as in the previous step.
The fit should be pretty tight. You will probably need to try several pieces before you find the right one.
This new piece of bamboo does not need to have any nodes intact. In fact, it's better if you use a lenght with no nodes in the way.
The bird that we are going to construct from this piece of bamboo will be what carries the air from the first "slow" chamber to the second chamber.
Step 5: Construct Your Bird.
I used a multi tool and a back saw for this step.
First, I cut the larger piece of bamboo into several pieces with a backsaw. These pieces are specific in length. I cut them so that each would extend about half an inch on either side of the node.
Next, I split all the pieces into various widths so that I had many to choose from and find the "right" piece.
Step 6: Smoother Is Better.
Next we sand the bamboo and the bird(s).
I generally use 2 different grits on bamboo. I start semi coarse (120) and finish with fine (300+).
You are trying to get the node as smooth as possible. You want to get rid of the ridge that goes around the bamboo, as this is where most air will be lost at when we apply the bird.
Don't worry, if you can't get it perfectly smooth, I'll show you a little way around that.
We will be choosing and smoothing our bird here as well. To make an easier fit I wrap the sand paper tightly around the flute where the bird will sit and use that as my sanding block for the bird. It'll get you close to where you need to be.
Remove sandpaper and check the bird and flute for a good fit. You may need to do this several times with several pieces that we cut earlier until you find the one with the closest fit.
Step 7: Carve the Bird.
We won't actually be carving a bird. We are going to be carving an air channel into the bottom of the bird. This air channel will allow air to pass from the slow chamber and into the sound chamber. Try not to go to wide with the channel, maybe a few millimeters wide at mose. Also, watch carefully that you do not carve to deep, you don't want to punch a hole through this piece, as it would be rendered useless.
I started by marking lightly with a pencil. This air channel should be long enough to go from one side of the node to the other with a little room to spare, to adjust later if we need to.
Step 8: Drilling
When drilling the holes, I start with the hole for the slow air chamber. I try to get it close to the node, but not so close as to poke through it. This hole should be at a 90 degree angle to the flute. Straight up and down. Then, I go to the other side of the bamboo about equal distance from the node and I drill another hole but this time at a 45 degree angle towards the front of the flute. When drilling in bamboo this size, I use a 3/32 drill bit and usually drill by hand. By that I mean I use my fingers to twist the drill bit, not a drill. I do this to maintain more control over hole size, placement, etc.
After drilling be sure to knock out any bamboo dust and pieces from holes and from flute body.
The next holes will be placed mathematically.
Step 9: Math
So, to try to get a good sound out of the flute, we need to apply a little math. For this instrument, we measure the length of the flute from the open end of the sound chamber (not the slow air chamber) to the Primary hole.
The first hole should be at 43% of the lengh of the flute
The second hole at 58%
and the third at 83%
The flute picture here has a length of 4 1/2 inches.
The first hole of 43% = 1.193 inches or 1 15/16
The second hole of 58% = 2.61 inches or 2 10/16
and the third hole of 83% = 3.73 inches or 3 12/16
All holes except Primary sound hole should be drilled at 90 degrees.
Be sure after drilling to knock out any bamboo dust and debris out as this can make you flute not play well.
Step 10: Now What?
So now we have the flute body, and the bird. Place your bird over the slow air hole and primary sound hole. The bird should be situated so that the air will blow from the slow air chamber and over to and across primary sound hole. The bird should not cover the primary sound hole, it should stop just before it. At this point you are simply checking to make sure you flute will produce sound.
Mentally mark where the bird has the best sound. Feel free to experiment with bird placement to get the best sound. You may even want to mark with a pencil where the bird will sit.
Step 11: Glue It.
Next we glue the bird in place. You'll notice in the picture there is a very thin piece of wood. this is simply a thin sliver of bamboo I cut from one of the birds that i didn't use for this flute. The thin bamboo is to help in the glueing process. I draw a bead of super glue around where I carved the bird and a tiny bit on the body of the flute. I place the bird onto the flute and move it to where I marked it for the best sound in the previous step. I do a quick check and blow through it once to make sure it doesn't need to be adjusted before the glue sets.
Once in its proper place, I lightly clamped it with a small set of locking pliers. Next, I use the super glue and timy bamboo piece to draw a bead around the "seam". I do this to make sure no air will escape from the sides or back of bird. Be sure to NOT get this into the air chamber you carved intou the bird or into the primary sound hole. If this does happen, then there will not be much you can do other than start over.
I let mine dry for several days before playing to let the air cure and really set up the glue.
Step 12: Enjoy!!!
After the glue dries, you're ready to play and enjoy the fruits of your labors. And because of the size you can always have one with you in your shirt pocket or in your blue jeans, and you can take your music with you anywhere.