Ancient people from Native Americans to Asians and Africans made flutes from local materials. Bamboo, a strong woody plant that is almost hollow, makes the ideal base for a flute. The length of the bamboo determines the flute's key. A 17- to 18-inch flute, a good size for your first homemade instrument, will play in the key of G.
Choose bamboo that is 3/4-inch to 1-inch in diameter. Cut the bamboo between 17 and 18 inches long. Make the first cut just behind one of the bamboo nodes and the second cut just before one of the nodes. When you're done, the flute should be open at one end.
Heat one end of the larger metal rod in an open fire or by laying it across a stove burner. Protect your hand with a potholder or oven glove and, holding the rod by the unheated end, insert the hot end into the open end of the bamboo tube. Push down, using the rod to burn out the thin walls between nodes of bamboo. Do not burn through the final partition; leave this section intact.
Wrap the sandpaper around the dowel and insert into the bamboo. Sand the inner edges smooth.
Measure 1 inch from the closed end of your flute and mark. This is the location of your mouth hole. Heat the smaller metal rod and burn a hole in the flute at this point. Use a sharp knife to clean out the hole and make it oval.
Measure 6 inches from the mouth hole and mark. Mark five other holes, each 1 inch from the previous hole. These will be your fingering holes. Heat the smaller metal rod, burn a hole centred over each mark. Use a rasp or the sanding stick to smooth out these holes. Keep these holes round and straight.
Play your flute to see how it sounds. Notes can be raised (sharped) by enlarging the finger holes. One way to tune is to play the flute with all the holes uncovered. This should be the lowest note of the flute, the "do" on the "do, re, mi" scale. Cover one finger hole at a time and tune each hole to the "do, re, mi" scale.
Finish your flute inside and out with a light coat of almond or walnut oil. Seal the holes with masking tape and pour the oil into the flute. Let it set for a few minutes, then allow it to drain. Brush a coat of oil on the outside.
Use an electronic guitar tuner to help you tune your flute. A large nail can substitute for the metal rod for burning the finger and mouth holes.
Always protect your hands from burns when handling the hot metal rods. Avoid breathing in the smoke from the burning bamboo.