Been rapping and tapping on everything of late.
My most recent success is a miniature version of
the tambiro but instead of an empty helium tank, 
I used a small, camping-type propane tank 
(the "squat" type measuring about 3-3/4" diameter 
by about 7" tall). Using this small cylinder is my 
idea -- inspired by the helium-tank (freon-tank) 
tambiro mentioned elsewhere on the internet.

The results have been quite successful. It sounds 
VERY nice & is much fun to play. The main difference
between it and the larger helium-tank version
(aside from being pitched a lot higher) is that
it's not played by tapping, but rather by plucking 
with the fingers kalimba-style.

I have some misgivings putting this thing on my
webpage because of the highly flamable nature 
of propane. I hereby disavow any responsibility
for any harm that may befall anyone tinkering
with propane tanks. I will only tell you what I did 
to make this thing. I do not suggest that anyone
else make one.

Here's what I did to ensure that there were no

- I first looked for a tank (stored with my camping gear)
  that was nearly empty (the liquid propane can be felt 
  and heard rolling around inside the tank when shook).

- Then I screwed on a propane torch head, took the thing 
  out in the woods, far from my house & turned the torch
  valve on full (unlit of course) - it was easy to hear the 
  gas wooshing out. Even tho the tank was almost discharged, 
  it took a while before it was completely empty (it stopped 
  hissing). Connecting the tank to a Coleman stove (etc) would 
  have worked as well. Repeating: I did this OUTSIDE - well away 
  from my (or anyone else's) house.

- Once absolutely sure there was NO HINT of gas hissing out 
  and that nothing was heard sloshing about inside, I unscrewed 
  the torch head & using a foot-long "J" bent-up from a 
  clothes-hanger, depressed the "valve-stem" -- a few seconds of 
  hissing was noticed, then silence. Now I knew the tank was really 
  empty. Then I took a HAND drill (not wanting to get a sparky electric 
  drill anywhere near potential propane vapors), with a 1/16" bit 
  & carefully drilled  a hole in the top of the tank near the screw 
  threads. No problem at all. I then redrilled the hole to 1/8" diameter.

- Next I mixed up a heavy solution of hot dish-detergent & water in 
  a utility pail, submerged the tank in this til it was nearly full 
  (because the drill-hole is so small, this took some time), madly 
  agitated the thing for a few minutes, let it drain & dry overnight. 
  This also served to considerably lessen the LP smell.

- Finally, I felt better about tackling a tank that previously
  held liquid propane! Way over-cautious I know, but ....

Concerning tongue size, shape and placement -- I just shrunk down the 
template shown in my "Helium-Tank Tambiro" article and applied these 
dimensions to the mini-tambiro. Truthfully, not much is critical - 
except the LENGTH of the tongues. In other words, just about any tongue 
size, shape and position similar to what's shown in the photo, can be 
easily brought into tune simply by CAREFUL and SLOW lengthening the 
two saw-cuts ends. As with the helium-tank tambiro, the pitch moves VERY 
fast with even a very small tongue lengthening. After having made several 
varieties of this instrument, I now try to make the high A tongue a bit 
narrower -- This seems to help the tone.

A note here concerning how I narrowed the width of the sabre-saw blade 
used to cut the tongues in this instrument -- The blade as-is was too wide 
to make the necessary tight turns when cutting the tongue. Seems to me I 
saw narrower blades sold somewhere, but can't find them around here. What I 
did was to clamp the blade tightly in a vise-grip and (using my hand-crank 
grinding-wheel which I find is much more controllable than a motorized grinding 
wheel) slowly ground off about half the width of the back side of the blade, 
taking care that the mounting end remained untouched. Obviously, the narrower 
blade could break more easily but with much care and EYE GOGGLES (for both the 
grinding and the subsequent tongue-cutting), this method worked fine for me. 
My instruments are normally made of wood and (despite once working as a 
tool and die maker) metal instruments are a bit foreign to me, so I take 
extra precaution and time when working anything metal.

I notice two different types of squat camping-stove type propane tanks. 
One has an easily removable plastic bottom-cap that enables the tank to stand 
upright, The other has a not-so-easily-removable metal cap tack-welded to the 
tank bottom. This second version is what I used. I had to work at it to get the 
metal bottom-cap off -- not to mention having to be constantly aware of the 
jagged edges produced in the removal process. 

A note about playing -- the tone and sustain while holding the instrument 
flat in the palm of my left hand is radically different than the tone/sustain 
if the thing is left unsupported along the bottom side (held against my chest 
& just the top, threaded part grabbed with my left hand). I like the tone with
the first method a lot better. The 2nd method is louder, but contains some 
undesirable overtones and ringing that is not at all present when held in my 
left palm. Varying how the tank was held in my left hand resulted in a wide 
variety of tones/sustain.

This mini-tambiro is pitched in the key of C. It's notes are:
- low C (do) (middle-column, bottom row)
- D (re) (middle column, top row)
- F (fa) (left column, top row)
- G (so) (right column, bottom row)
- B-flat (Ti-flat) (right-column, top row)
- high C (do) (left column, bottom row)
This is the same scale (but in a different key) as my "full-sized" helium-tank 
tambiro described on my web-site. While I noted this scale on several of the 
instruments I found on the internet, I also found tambiros using other scales. 
On another one I built I pitched the thing a couple of notes lower, with good 
Dennis Havlena - W8MI 
Mackinac Straits, northern Michigan

Click here to access my webpage