Before Yim Saing and his son can make their flutes, they first have to find the right size bamboo tree. It must be small enough to provide the relatively slender barrel of the flute and should not taper much. Once the tree is located, they cut it down with a saw and then cut the usable parts of the tree into the proper length for carrying home.
With the lengths of bamboo at his home, Yim Saing and his son measure where to cut the bamboo for flutes with a segment of coconut leaf that is just the right length. They then make a mark on the wood. Next, the wood is sawed through at the mark to create a flute-length piece of hollow bamboo. The lengths of bamboo must be dried for several weeks and after that they are placed in the smoke above a low-temperature cooking fire to complete the drying and curing process.
Picking up one of the bamboo flute "blanks" they dried before we arrived, Yim Saing looks it over carefully to make sure it’s in good order.
Next, he takes a thin piece of coconut leaf that was used to cut the flutes to length and he folds it exactly in half.
Using a sharp knife, he scrapes a thin strip off the outside of the length of the flute. Next, he takes the folded leaf and lines it up on the flute, next to where he scraped.
With one end of the folded leaf at the end of the flute, the other end marks the middle of the flute, which is the place to drill the fifth hole. With a pencil he made himself from graphite he took from flashlight batteries, he marks the exact spot.
Next, he folds the leaf in half again, and then once again. Each fold in the leave is used to mark another hole until seven adjacent holes are marked. One fold is skipped, and the eighth and final hole is marked on this side of the flute. During this process, he often compares the flute he is making to his personal flute, to make sure everything is in order.
Next, the flute is rotated and another strip is scraped along this side.
Then, the three holes are marked on this side. One of these holes is next to the end where the flutist blow and is shaped to cause the "whistling" noise of the flute. The other two on this side are used just like the eight on the other – to change the tone of the flute when a finger is placed over the hole.
To drill the holes, Yim Saing builds a small fire and places the sharpened ends of six metal rods into the coals. The rods are all about one and one-half feet long but vary in diameter.
The smallest is about one-quarter inch – about half the thickness of a wooden pencil. The largest is exactly the size of the finished finger hole; the others span the gap. When the tip of the rod is red hot, Yim Saing pushes the rod against the bamboo where the holes is marked and twists the rod. The bamboo smokes and the rod slowly burns its way into the wood. After a minute, Yim Saing puts the smaller rod aside and takes the next largest one from the fire. He pushes this rod into the hole he just made with the smaller rod, enlarging the hole slightly as it burns. He uses six rods – each a little bigger than the last – before the hole is the right size. The same process is used on each of the ten finger holes on the flute.
The hole that the mouth blows through is made differently. With a small sharp knife, a square hole is cut down into the bamboo.
The size of the hole determines the base tone of the flute. Once the hole is slightly longer than wide, the end away from the mouthpiece is carved on a slant, to create the "whistling" as the players breath passes underneath this hole and through the bamboo tube.
Next, this end of the flute is partially plugged. A round piece of wood is carved to fit tightly into the flute opening.
It is sawed to length so when inserted it is flat with the end of the flute and extends into the barrel until it is just short of the hole. The round wood is flattened the length of the plug on one side, allowing the flutist to blow air past the plug and beneath the whistling hole. This plug may be glued or it may simply be tightly inserted.
When all the holes are finished, the flute is polished with a small piece of sandpaper and the smokey residue from the drying process is removed. The flute has a dark, burnished look.
Yim Saing is able to make five flutes in a day, if the wood is cut, dried, and ready to be worked. His son can make as many as ten.
Of those fifteen flutes, perhaps ten will be good enough for a serious musician to use. Others will be used by the many Cambodians who enjoy music in their daily lives.