Step 1: Find Materials
2.75" inner diameter
3.25" outer diameter
Plastic disc for membrane:
approx 0.5mm? like milk jug plastic?
coils are almost 3/8" diameter
Glue able to bond plastic to cardboard
Step 2: Assemble
and corkscrew a few coils of the spring through. Glue it in place.
Then glue the plastic membrane to the cardboard tube.
Put a bead of hot glue on the end of the spring to avoid a sharp end shaking around.
Step 3: Shake then paint.
So this is how mine was made judging by how it looks. Hopefully you can duplicate it since the sound is amazing!
I intend to experiment with making a larger one in the near future. I've got a big heavy fiberglass cylinder as shown in the picture. :-D
If anyone knows about resonance frequencies and has some advice let me know since I believe that's how the dimensions are found.