This tutorial covers how to construct a hank drum, an instrument invented by Dennis Havlena that imitates the extremely expensive and difficult to obtain Hang Drum. This instrument can be built for $27 if one has all the necessary tools. A bargain considering one of these propane tank drums recently sold on ebay for over $10,000. The original instructions for this project can be found on Dennis Havlena's site at http://www.ehhs.cmich.edu/~dhavlena/for-webpage-lp-hang.htm
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Step 1: Preparing for Construction
The construction process is quite simple and only requires a few supplies.
You'll need an empty propane tank. Try and find a new one that has never been filled to avoid horrific injury. I found my at Wal-Mart in the camping section for $27.
A drill or dremel, a saber, jig, or similar electric saw, hack-saw blade, wrench, file, and electric tuner. If you do not have a tuner, you can use one of several tuner programs that install onto your computer and use a microphone. Try checking http://www.mymusictools.com/download/tuner-software/ for one of these programs.
Step 2: Removing the Valve
First, remove the valve on the top of the propane tank. This mechanism is liquid-welded on and very difficult to remove. The best method is to use a wrench and then an extender such as a pipe to provide additional leverage.
Step 3: Remove Welded Ring
Next, remove the welded metal ring attached to the tank bottom. Try to avoid damaging the tank as this is where your notes will be cut. Chiseling or manually stressing the joints should allow you to "de-ring" the tank very quickly. File down any remaining nubs.
Step 4: Preparing for the Cut
Print off and apply the tongue template to the top (what used to the bottom) of your tank. Mark where the tongues will be. If you will be changing the tuning of the drum as I did, go ahead and mark the tongues and adjust accordingly later. The template can be found at http://www.ehhs.cmich.edu/~dhavlena/lp-hang-template.jpg
To prepare for the cut, drill small connecting holes or dremel out a slit long enough and wide enough to insert your saw blade. Proceed to cut along the guide you traced earlier stopping about 1/4" from the end. Do this for every tongue.
Step 5: Removing Magnetic Filings
You have probably noticed the buildup of magnetic filings in the drum. Once all slits have been cut, try running a high pressure stream of water, as from a garden hose, through the tank to clean out the shards so they do not cause a rattle.
Step 6: Tuning
Now for tuning. Be very careful not to tune too far as it is a pain to raise the pitch of a note. To tune start by taping down all the notes not being tuned to eliminate overtones and harmonics. Then, starting with the lowest note, proceed to slowly hack-saw (using only the blade) the tongue longer constantly tapping and measuring with the tuner to see when the note is in tune. Do this for all the tongues and do not get impatient. If you do mess up and cut too far, you must slowly trim down the top of the tongue to make it lighter and thus raise the pitch. Pleas note though that this is an extremely lengthy process.
Step 7: Playing the Instrument and Summary
When playing the instrument, it is recommended that you wrap a bungee cord around the tank to help eliminate some ring and provide a better tone. Also, do not play the drum on a hard surface as it loses a large amount of it's sound. The drum will play better held in your lap on standing on carpet or grass.
I built mallets for my drum and I believe they provide a better tone. The mallets are simply two Spiderman superballs stuck on the ends of dowels. If you play with your hands, lightly tap the tongue about 2/3's of the way up to get the best tone.
My instrument was constructed for the state of Georgia's Science Olympiad where it won first place. It was used as the bass instrument and was therefore tuned much lower than what is optimal. I recommend you use the pentatonic scale Dennis Havlena uses for his.
All credit for this project goes to Dennis Hevlena, the inventor and original documenter. His site and instructions can be found at: http://www.ehhs.cmich.edu/~dhavlena/for-webpage-lp-hang.htm
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