Posted by Rick Denney on June 03, 2002 at 11:32:46:
In Reply to: Re: Compressed Air? posted by Matt C. on June 02, 2002 at 23:27:20:
Indeed, compressed air when pushed through a small hole can move at high speeds and carry dangerous things with it.
I would not worry about blowing compressed air through a tuba, however, though I don't see the point. The smallest hole that the air will pass through is the nozzle of the blower, which is much, much smaller than any of the tubing in a tuba. As others have mentioned, the air will slow down in a hurry, with the result that it won't be effective. By the time it's coming out the bell, it's not likely to move fast enough to accomplished anything. If you blow from the bell end, you'll just blow the debris further into the horn.
I would worry about filling a tuba with compressed air. If you jam a rubber-tipped nozzle into the receiver, you might be tempted to plug the bell as a sort of impromptu science project. Don't. Tubas are not made to hold that sort of pressure. At the very least, you are likely to turn one of your tuning slides into a self-destructing projectile. You should never force more pressure through a tuba than what your lungs can produce, in my opinion.
In my youth, I conducted such a science project with a roller bearing from a car axle. I mounted the inner race in a vise, and used compressed air against the roller cage to see how fast I could get it to spin. The bruise on my face, about an inch below my lucky eye, took two weeks to disappear. I figure the bearing was spinning at about 20,000 rpms when the rollers blew apart the cage.
Rick "who had new respect for centrifugal force and 'science' projects after that" Denney