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
Poke a small hole in the center of the plastic membrane (hot needle?)
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.
Try it out by shaking. If it works, paint it and make it look awesome.
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.