This thing is safe because it is made froma NEW, NEVER-BEEN-FILLED twenty-pound (that can hold 20 pounds of liquid propane) LP tank that our local HWI hardware store sells for about $30. Later note - Home Depot has them for some $26.
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Because of the possibility of an explosion and/or fire when tinkering with a previously-filled LP propane cylinder, DO NOT MAKE THIS INSTRUMENT FROM A PREVIOUSLY-FILLED PROPANE TANK! Use only a NEW, never-been-filled-before tank. So - down to business. The thing is constructed in a very similar manner as the helium-tank tambiro. The tongues are larger and the cylinder metal is a lot thicker which makes for more difficult saber-sawing. Otherwise it's much like making the helium-tank version.
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Immediately below is a template showing the placement, pitch and size of the six tongues (notes). When you print it out, make sure that the 1 inch scale on the drawing measures an inch on your print-out -- if not, adjust your printing process until it does. Now lay a piece carbon paper (or simply heavily blacken the back-side of each tongue on the paper using a #2 pencil) then tape on the template and transfer the template tongue layout & size to the actual tank.Click here to see this template - and also a small photo of the completed instrument
To lessen weight and to provide a bit of a "sound-hole", I removed the valve and associated piping - this was not easy as the valve assembly is screwed very tightly into the tank. A short length of threaded pipe screwed into the valve assembly and wailed on with a hammer did the trick. I've found that the thick metal of this heavy 20 lb tank makes it hard for a "regular" type saber-saw metal-cutting blade to negotiate the curved part of the tongues. I modified an off-the-shelf blade by clamping it tightly in a vise-grip and slowly grinding 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 makes a blade that easily follows the tongue's curves. I reverted to a regular, unmodified blade to cut the straight parts of the tongues. Note: even though the tank is new and has never been filled, you should do whatever is necessary to be abslolutely certain there is nothing whatsoever in the cylinder before poking any holes in it. Bear in mind that with the newer type tanks, when you simply turn the valve, nothing will come out -- this might lead you to wrongly believe that it is empty! Anyone at any propane filling business would be able to tell you in a minute whether the tank is indeed completely empty. I recommend this route. Drill three 1/16" (or so) holes about 3/8 inch from one of the tongue line's ends -- carefully tilt the drill to elongate the 3 holes into a slot into which a metal-cutting saber saw blade can pass. Carefully cut along the line to within 3/8 inch or so of the other end of the tongue's line. Repeat for the other 5 tongues. Try your best NOT to cut too much and have a note lower-pitched than desired, but if you do do this, it's not fatal. I've had fine luck raising a tongue's pitch by temporarily wedging the tongue open 3/16" or so then carefully (using a small grinding wheel clamped into an electric drill) grind off some of the length of the tongue until the pitch is raised the desired amount. This grinding process takes considerably longer than the initial saber-saw pitching mentioned in the above paragraph -- all the more reason to go slowly and get the pitch right the first time (with the saber-saw). One more (later) comment: occasionally the end of a tongue will "sink" below the overall level of the tank once cut. I fix this by prying up the tongue with small screw drivers, inserting a metal wedge (I use a mason's chisel) & hammering in the wedge until the tongue is about 3/8" above the surrounding tank surface. With the chisel removed, the tongue will spring-back some, but should remain at or slightly above the surrounding tank surface. You may have to do this a few times until you get it right. Tuning is easy, but somewhat critical (the pitch moves quite fast). Starting from the lowest pitched note (center column, bottom row), I just slooowly lengthened each tongue (in very small increments -- testing CONSTANTLY) until it matched the desired notes as compaired to a piano. The trick here is to CUT SLOWLY and check the resultant pitch VERY often. The notes sound best if you sharply slap the tongues as quickly as possible without much dilly-dallying. It takes a few minutes of experimentation to get this hitting bit right. Also, just where on the tongue you tap is important. Experiment. I should note that you don't seem to have to be as careful slapping this instrument's tongues as you do with the helium-tank version -- probably due to the thicker metal, however you should still try not to linger too long when whapping a tongue. These tanks are considerably heavier than the helium or freon cylinders, but are not that unwieldy when played, handle-end down (resting on the ground or a support), nestled between your legs, while sitting on a porch-step or other low seat. Concerning "key" -- I pitched mine in the key of G -- the lowest note (middle column, bottom row) sounds the G note in the octave below middle C on piano. Dennis Havlena - W8MI Mackinac Straits, northern Michigan 4/10/07
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