How to Build a Hank Drum

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Introduction: How to Build a Hank Drum

About: I am a filmmaker, student, and tinkerer. I love designig and building devices instead of purchasing them. Instructables is a great way to do that and share with others how to do the same...

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

This tutorial can be watched or read depending on your preference:


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

2 People Made This Project!

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120 Discussions

Awesome drum-we made 1 for a band (we also use jwilson27s altoids tin guitars and a bass. It works good. Also, could you use different size tanks for different sounds? We made ours with one whole octave in the key of low C

3 replies

I think the innitial depth of the drum determines the octave? thoughts?

Nah, the size of the tab determines the hertz of the note. Longer, wider tabs will be lower. Shorter, thinner tabs will be higher.
You just tune them to the octave you want. The size of the drum itself will change overtones of the tank, and will create different rings depending on how long the sound has to bounce around inside.

Source: I've made over 50 of these. Great fun.

Hi :] have you experimented with tongue shapes? Fore example narrowing to the point vs widening to the point. I assume wider tip will give it more sound, because there is more vibration?

And maybe any idea how to create my own tongue layouts, how to calculate approximate sizes of the tongues for desired notes?

Hi, Hermes,

My drum is great but one note just doesn't "ring" right... kind
of dead, though in tune. Do you have any ideas to get that note to
"ring" like the rest? I'm afraid if I file or cut anything I'll change the pitch, which is right on now, but dull sounding.

Many thanks!

Hey Guys

I live in Denmark where the standard propane tanks are either smaller or larger, and have a slightly different shape. Do you have any tips on how to adjust the shape and size of the steel-tongues to different sizes and shapes of propane tanks?

The best regards

1 reply

Hi Frederik, the pitch of each note (in hertz), f = sqrt(stiffness/mass). The stiffness comes mainly from the thickness of each tongue (stiffness = t^3 and is therefore more critical than the mass), so if your drum has thicker wall section the pitch will go up and you will need longer and less wide tongues, to get the same pitch. You can make it artificially less stiff by filing it down and the tongue connection point (which is where it moves, so is the most critical place to influence the stiffness). Hope this helps. N

For those lacking a good ear or a dedicated tuner, decent instrument tuner Apps are available for iOS and possibly others (I don't have an Android device).

I really liked the one called spin tuner, but it doesn't seem to show in the App store any more.

Thank you Dennis! I made my first drum according to his template. My neighbor's grandson like playing it so much that I gave it the paint job you see pictured and had her give it to him for his birthday. (And it's a tribute, not a model.)
I've made a second one with a different pentatonic tuning. Both are from recycled tanks.
Anyone have tips on removing the methyl mercaptan smell? I soaked mine in a bleach/water solution which did the trick, but causes instant rust all over. Makes me worry what it's doing to the inside of the tank.

r2 hank drum.jpg
6 replies

Hello, when you take the valve out, before you cut, you can fill the tank with water and dawn soap, or something equivilant. let it sit for couple hours and deodorize ;) I have a question for you.. I am having trouble figuring out the sequence in which to cut the notes. Do you cut and tune one at a time? I am not familiar with musical notation, but have been playing piano by ear for many years and can hear where i need to be. Any suggestions? thank you :)

When I make them I cut out pilot holes, then I cut all of my arcs.
Once all of the arcs are cut, then I start tuning them from lowest to highest.

Sometimes I'll just get them close to being perfect, then go back around again to fine tune them. For example, I would tune my low and high A's to 448Hz and 229Hz the first go around, then fine tune them down to 442Hz and 222Hz after everything else is tuned.

I always leave them a little sharp because paint will flatten the note. Time also flattens the note. Every drum will fall flat after some time, so tuning them sharp makes them sound crisper for longer.

Hope this helps!

I tune my guitar with 440 Hz set for the tuner for every note. Why can't this work for my drum. My tuner does't go lower than 410.

You might try fresh lemon,lime,or even grapefruit juice.Use as much as you can and use a brush where you can after it has sat on a while.

Hey do you happen to have a copy of the tongue template before the website for it went 404 on me? Thought I'll ask someone who posted a long time ago. Thank you, and sorry for the late posting :D

Can anyone can suggest a way that I can be certain a standard propane tank isn't pressurized? I've got one that I'm 99% sure is empty. I can open the twist valve, and no sound or hiss, but i believe there's a 'safety' valve that only allows a release when it's attached to a hose/stove/whatever - which I don't have. Can I take it into a home depot and just attach a hose and then try opening the valve? Is there a special tip on certain hoses that engages the safety valve? I found a screw on the side of the head that I'm told is the 'bleeder valve' and I've removed that completely - no hiss at all - wouldn't that be a pretty solid guarantee? If I remove the head slowly (outdoors) would that let me know, or would it just fire off like a rocket the minute I break the seal?

i went to our buddy craigslist. found a guy who brought me tanks somebody gave him, sold them to me for 10$ each. but i'm still looking for freebies. you might post a "wanted" ad on craigslist, and check your local "free-cycle" boards. if there is gas in them, Bar B Que like crazy :-)

LPG tanks have a short lifespan because the gas causes the metal to become brittle. you can find them at any garbage dump or recycling yard. they are usually very cheap, because you can no longer use them for gas.

the steel is really tough. i'll bet you'd go through quite a few blades cutting this.

Depends on the blades, and how patient you are.
I use anywhere between 1 bimetal jig saw blade, to 4 in any given drum.