Homemade Bells

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My neighbor was telling me about these Tibetan Bells that he had seen at someone's house. Basically it was an old gas cylinder that was cut in half and hung so that it could be struck with a mallet and rung.

Step 1: Acquire an old gas cylinder

This sounded very cool and fun, and since I seem to have a bit of spare time these days, I thought I would give it a try. I called around and found a welding supplier that had plenty of condemed gas cylinders (bottles). We're talking about the big oxygen type tanks that welders use. Anyway, the condemned bottles are basically scrap metal and I was able to get some for free.
Gas Bottle

Step 2: Cut the bottom off of it

The guy at the welding supply place suggested an oxy-acetaline torch. They cut off the tops of the bottles to ensure that they can't be used. I picked up a few of these while I was there. It turns out that the torch does not offer a very straight cut.

On my way home, I stopped by my local neighborhood welding shop and tried to offer them a six pack of beer to cut the the bottoms with a torch. After the young guy looked at me like I had six heads and was a side dish he didn't order, he went in the back to get the old guy -- the dude who has been welding for a hundred years.

This guy says, "So your gonna make bells, huh?" Cool. He then says that "You never really know what was in these things, so it's not a good idea to use a torch if you like keeping your body in it's natural uncharred state". He then mentions that he has this really big bandsaw that would make short work out of my bells. This is cool I think. He then mentions that unfortunately they are really busy and they can't get to it before Wednesday (This was on a Friday). I mention the beer and told him that I would try it on my own over the weekend and bring them back if I didn't get anywhere.

He never really bit on the beer references so I guess I'll have to drink 'em on my own.

Note: Oxygen tanks are made from steel and are pretty hard

sawzall Having gotten somewhat smarter from my recent woodworking projects, I decide to start on the small one to see how it goes. I dig out the trusty sawzall (thanks dad) put on a metal blade, and spray a little WD-40 on for lube, and dig in. Well actually, I drilled a hole in it first but the blade was bigger than the hole, so I had to cut on the outside of the cylinder for a while with the sawzall until I got to the point that I could get the blade inside. Once I got the blade in it went fairly quickly and I was able to cut the bottom off in about 20 minutes.

Note: Don't try to cut a straight line around a cylinder by eye. Make a line to follow instead

Between my drill hole and my wild cutting, I had a pretty ragged edge. It turns out that the smoother the edge, the better. Needless to say it didn't sound bad but not great either.

Note: The science of the acoustics of bells is pretty serious stuff

It turns out that a search for "bells homemade acoustics" returns quite a few hits in the major search engines. After some searching over a couple of days, I finally found some decent links: I also found this cool program at the Church Bell site that will do a sound analysis of a bell and point out all the frequencies. To make a very long and very complicated explaination of a-bunch-of-stuff-I-don't-quite-understand-yet short and to the point, bells do not have one frequency (tone). They have a strike tone, a hum tone, and a bunch of other tones in between as well as overtones of the aforementioned tones. This makes it very difficult to measure the musical note of a bell since it has such a complex sound. Suffice it to say, I have analyzed my bells with the program but I don't know what to make of the results ;->.

Note: Being a geek who likes to collect electronic sound related stuff can come in handy

It turns out that I can plug my digital multimeter that can read frequency into my SPL meter (tells you how loud something is) and I can see the frequency that my bells are ringing at. I also can hook up my tone generator, and play tones until I get one that sounds like my bell. Then I can look at the tone generator and see what frequency the bell is although this is pretty subjective.

Note: Bells are very complex and do not have one tone

Since bells don't really have one tone, having this homebrew measuring equipment doesn't really get me very far. Did I mention that the idea is to make a large bell xylophone with 4 or 5 bells to hang at the end of the driveway for the neighborhood kids to play with? Gotta love interactive "art". So I need to figure out what length bell will give me what tone.

Note: Even Einstein had to start somewhere

Since the bell theory that I have been able to find focuses on conventional bells and mine aren't (not that I really understand it anyway ;->), and since I have yet to find anybody who has done this before, I'm on my own. Unfortunately, it takes about 45 minutes to cut a section off of a large cylinder, so exprimentation takes time and effort (and plenty of saw blades).

I've decided to record the tones from each bell as well as the general dimensions and post them here so that hopefully, other folks can take advantage of some my sweat and callouses.

Note: On the internet everyone can hear you scream

During my lovely traversal through the search engines, I ended up sending email to 3 or 4 folks involved with various websites that I came across asking for help, guidance, wisdom, or a point in the right direction.

The only person who was kind enough to take pity on me was the wonderful Bart Hopkin at Experimental Musical Instruments. Besides emailing me with a good primer and some good direction he also pointed me to oddmusic.com which also has an associated yahoo group. By the way, make sure to check out the photo gallery at oddmusic. There is some cool stuff in there!

The very nice folks on the oddmusic yahoo group pointed me to another good yahoo group: tuning - the Alternate Tunings Mailing List. These folks are way smart and really know about musical theory. They too took pity on me and have started to offer me some really helpful info as well.

Note: As easy as these are to make, very few folks seem to make them

Everybody that I mention this idea too seems to think it cool, and everybody who hears the bells ring is pretty impressed that something so mundane and ugly can sound... well, nice. Since cutting the bottoms off of these tanks until you get a sound that you like is not at all difficult, I'm really surprized that you don't see more (if any) of these things.

Page 2 - See and Hear the Bells and watch the Project progress

Page last updated 28-July-2001 Comments or questions or helpful hints to flint