To hear how it sounds, listen to the .mp3 audio file in the last step.
Step 1: The Parts of the Recorder
The spacing and size of the holes in the body are copied from a store-bought plastic recorder.
The mouthpiece is composed of concentric layers of different size pipe. The pipe diameters are: 1/2" CPVC (smallest diameter used for hot water), 1/2" PVC (the layer around it with a section removed to create an air channel), and 3/4" PVC (to cap the top of the air channel).
The air channel conducts the air you blow to a sounding hole. A wedge shape at the hole interrupts the air flow and creates vibration and sound.
The fingering holes in the body modify the pitch of the sound by creating different amounts of resistance to the air passing through the pipe. Opening all the holes lets air escape with less resistance by the easiest route, through the first holes. Closing all the holes creates a longer column of air inside the body, and more resistance, which results in lower notes.
Step 2: The Mouthpiece
My mouthpiece parts fit so tightly that no glue was needed.
I cut the 1/2" PVC channel and put it in place to mark the size of the rectangular sounding hole. Then I removed the 1/2" PVC, drilled the hole, and touched it up with an X-acto crafts knife. You need a narrow and sharp blade to get in the hole and carve out the wedge-shaped edge of the hole.
I put the wooden dowel plug right up to the start of the sounding hole. Setting it further back toward the mouth changes the pitch and allows some tuning. I used a metal drift pin and a hammer to set the plug inside the pipe.
Step 3: Finger Hole Size and Spacing
FINGER HOLE SPACING:
There are seven finger holes and one hole for the thumb on the opposite side of the body -- the same as on a recorder.
On a recorder, double holes at #6 and #7 help get half tones. I elongate my holes and just half-close them when needed.
Step 4: Shaping the Finger Holes
In the raw hole, there is a pocket of air inside the hole underneath the finger. I like to bring the finger down a little lower, thus reducing the pocket of air and turbulence inside the tootophone body. It probably results in a cleaner sound.
I made a special tool to get inside the drilled finger holes and scrape the burrs from inside of the tootophone body. (A tiny knife with a bent end, made of stainless steel welding rod.) That, too, reduces turbulence and makes the instrument easier to play.
Step 5: Trimming the Mouthpiece and Body
I cut the mouthpiece 2 1/4" from the sounding hole. I cut the body 1 3/4" from the #1 hole. No science involved there. I just eyeballed it.