Bamboo Slide Whistle

This project shows you how to create a bamboo slide whistle with very few materials or tools. It's a fun way to demonstrate and explore how pitch height corresponds to material length.

Tools:

• Hand drill and 3/16" bit
• Small hacksaw
• Hot glue gun
• Sandpaper
• Metal file

Materials:

• Bamboo with one closed end at the node
• 3/16" dowel
• Round dowel that is slightly larger than the bamboo's bore (mine was 3/4"). A wine cork might work as well.

In all steps below, I recommend using a bench vise to help secure your work--but be careful not to clamp your bamboo too tightly as it might crack!

1. Find a piece of cured bamboo with multiple nodes.
2. Make straight cuts with a hacksaw just below two nodes of the bamboo so you end up with a piece that is open on one side and closed on the other.
3. I recommend using a piece of masking tape at the cut lines to prevent the bamboo from splitting or cracking.
4. Next, use some sandpaper to clean any rough spots. You may also need to clean out the paper-like material from the interior, using a screwdriver or rounded file.
5. Test that the bamboo is airtight by blowing into it. If air escapes anywhere, it may be cracked, so find another piece to use.

In this step, we will make a rod that slides through the closed end of the bamboo and has small blocks of wood on either side.

1. Start by drilling a 3/16" hole in the closed end of the bamboo. Expand the hole slightly by rotating the drill handle while the bit is spinning. The goal is a hole slightly larger than the dowel so it slides easily.
2. Next, use the larger dowel to create a block that fits inside the bamboo and slides easily. Reduce its outer circumference with a piece of sandpaper, rubbing symmetrically on all sizes. When it fits inside without getting stuck, cut the block to 1/2" to 3/4" in length. Then, drill a 3/16" hole in the center, using a piece of tape on the drill bit to help find the desired depth.
3. Cut the 3/16" dowel to approximately the length of your piece of bamboo.
4. Stick the 3/16" dowel through the bamboo and use hot glue to fix the block on the slide's end inside the bamboo.
5. Make another small block from the larger dowel to fit on the end of the slide and use hot glue to lock it in place.

The ramp is the sharp part where blown air is split between the inner and outer parts of the instrument and the sound originates. The ramp should be smooth, without splinters or burrs, as imperfections negatively affect the sound quality.

1. Cut a vertical notch near the open end of the tube with a hand saw (or coping saw) about 3/4" from the opening. Cut about 1/3 of the way through the outside diameter.
2. Make a 45° angled cut about 3/4" from the first vertical cut on the opposite side from the opening to approximately the same depth. Don't cut all the way to the vertical cut, leaving a notch on either side.
3. The notch can come to a point, but it's best when the bottom of the notch has a flat section about 3/16” – 1/4” long.
4. Use a screwdriver to carefully pop out the wedge-shaped chip.
5. Use the screwdriver or a rounded file to gently clear splinters or burrs from the ramp's sharp edge inside the instrument.

Next, we need to make a windway that channels blown air toward the ramp inside the whistle.

1. Find a dowel large enough to fill the entire bore (inner diameter) of the bamboo. I used a 3/4" round dowel for mine. (A wine cork might work for this.)
2. Reduce the size just slightly with sandpaper so the pressure of placing the dowel doesn't crack the bamboo.
3. Use a flat metal file on one side of the dowel. This flattened portion should be slightly larger than the distance from the ramp to the end of the whistle, about 1".
4. Gently push the dowel into the bamboo, with the flat side at the top. Experiment by blowing into the end to see if you get a sound with the dowel in place. The dowel should go in to roughly the same edge as the first vertical cut of the sound hole.
5. Once you get a sound, mark a line on the dowel and cut the excess material.
6. Next, use hot glue to keep the block in place.
7. Lastly, you can create a mouthpiece shape by cutting through the end of the whistle at a 45° angle.
8. Use a rounded file and sandpaper to get rid of any rough spots.
9. Lastly, sand the entire instrument to remove discoloration in the bamboo and make it smooth.

Blow through the whistle and move the slide to create fun sounds!!