Whistle-building is a fun craft that can lead to a fulfilling hobby of building instruments to play a variety of tunes. A homemade whistle can be constructed from simple PVC piping, as long as it is stiff and thin enough. You can make your whistle to play in any key you desire by varying the size and distance from the end-cap of the finger holes. The mouthpiece is the most important part of the whistle; it may take a few tries before you find the shape that suits you best.
Measure and cut a 30.5-centimetre section of PVC pipe, then cut a separate 3-centimeter section of pipe and a 3-centimeter section of a wooden dowel. The dowel's diameter must match the inner diameter of the PVC pipe. Keep all cuts as straight as possible. The small piece of PVC will be the windway top, where the air passes.
Cut one corner of the wooden dowel at approximately 45 degrees, beginning about halfway along its length, to make a fipple, the wedgelike plug near the mouthpiece that diverts breath to produce the tones. Sand the longer portion of the resulting parallelogram very slightly so that a small amount of air can pass through it.
Place the body of the whistle in a vice and trace a line lengthwise on top of the PVC with a pencil and a ruler.
Measure and mark a line 3 centimetres from one end of the pipe. Draw a line 5 millimetres from each side of the centre line running from the 3-centimeter mark to the end of the pipe.
Cut out a slot along the two 5-millimeter lines all the way to the 3-centimeter line. Peel the material up and cut it with a utility knife. Then cut the bottom corner off at a 45-degree angle so that its shape matches the mouthpiece. Keep all cuts as straight as possible.
Cut the shorter section of the windway top so it can be stretched around the whistle body. Slide the wooden fipple into the whistle body so that its end makes about a 5-millimeter opening with the slot of the whistle body. Stretch the windway top to slide it over the whistle body and fipple.
Mark the locations along the centre line where you want your holes to be. The locations and diameters of the holes will depend on what key you want your whistle to play. See ggwhistles.com for a measurement guide for the key of your choice.
Bore the holes through the whistle body using a pair of sharp-pointed scissors. Use small twisting movements to begin making each hole, slowly increasing the diameter. Stop to measure the diameter frequently.
Sand the bottom of the mouthpiece with fine-grit sandpaper and lightly sand each hole and cut. Make sure to brush off any residual PVC or wood dust before playing your new instrument.