I've been in love with the Hang Drum, but alas, I haven't been able to find an affordable one to purchase yet (but you can read more about that adventure on my other posts).
Here's the story about my creation process in building my own Hank Drum.
Step 1: Purchase a brand new 20 lb propane tank. NOTE: like Dennis recommends, ONLY USE A NEW NEVER BEEN FILLED TANK.
Step 2: Remove the value. I released the air pressure inside the tank with a screw driver by turning the screw on the side of the valve. Then I used a large adjustable wrench and some leverage to move it. This will take some strength and possibly addition help to hold the drum and turn the wrench. In the picture, you'll see how I secure the drum with a crowbar.
Step 3: Remove the bracket from the bottom of the tank. This will become the playing surface of the drum. I used a 10" adjustable (monkey) wrench, tightened to the dimension of the metal on the bracket. I then worked it back and forth over each weld until the bracket broke free. After breaking off the welds, be sure to file down the weld mounts until they are flush with the surface of the 'drum head'.
Step 4: Printout the pattern from Dennis's website and enlarge the pattern on your scanner or a copy machine until it is the correct dimension. Position this pattern overtop of the "drum head".
Step 5: Trace the pattern onto the surface of the drum. I used a sharpie pen to copy it. This turned out to be a pretty good idea, as the saw scratched up the surface pretty good and I was using oil to help the cut. If I had used a pencil or a water soluable pen, the lines would have been messed up.
Step 6: Cut the tongues out with a jigsaw and metal cutting blade. Follow Dennis' advice on grinding down the blade to cut the tight radius. I went through two blades to cut all of the tongues out. Here's where I made one variation from Dennis's recommendation. Instead of drilling three small holes (my cordless drill battery is pretty shot anyway), I used a dremel tool with a cut-off wheel to start the cut, right on the line of the tongue. (I apologize that the image is sorta blurry). From here it was easy to cut out the rest of the tongue. NOTE: As Dennis recommends, make sure that you stop short on each tongue. This leaves you room to tune each tongue later.
Step 7: Tuning the drum. This is the step where you have to be the most careful. You'll need a digital tuner to complete this step. I started with the biggest tongues first. I used a hacksaw blade with half of it covered in electrical tape, to extend the cuts of each tongue until it was in tune. Note: as shown in the picture, I used eletrical tape to deaden the other tongue while I tuned a specific tongue. I also followed Dennis's advice and left the larger tonque's "open" when tuning the highest two tongue. I am still not completely happy with the tuning or performance of the highest two notes, they "sound" but they don't ring very long.
Step 8: Add a couple of rubber tie down's to the middle of the drum. This helps to dampen the ringing.
Step 9: Play your drum!
First of all, props to Dennis Havlena for his incredible ideas! Keep 'em coming...
Second, I took a dowel, inserted it though the value hole, placed the end on the backside of a tongue and then hit it several times with a hammer. This pushed the individual tongue "up" above the surface of the tank bottom. I think that this make it more playable.
Third, I've also been playing around with the strategic placement of modeling clay on the tank bottom to help eliminate some of the overtones, attempting to get a purer sound.
Fourth: Check the "How To" link section on the sidebar of the blog for additional blog entries on Hank Drum construction.
I'll post a YouTube video once I get a moment to record something.
Join the Hank Drum Collective: http://hankdrum.collectivex.com