Klarinet Archive - Posting 000268.txt from 1997/11

From: Dee Hays <deerich@-----.net>
Subj: Re: Vacuum
Date: Thu, 6 Nov 1997 19:22:18 -0500

For me, blowing into the joint has always been a successful way to test
for leaks. Here is the procedure that I use.

1. Take the upper joint by itself and close all the holes with the left
hand as if you were playing. Plug the bottom of the joint with either a
cork (if you have one) or by placing it on the meaty part of your palm.
Put your mouth around the cork on the upper end of the joint. Then blow
with the same force that you use when playing. If there are no leaks,
you will feel like you can't blow through it. With even a small leak,
you will be able to blow through it fairly easily. To pinpoint the
location of the leak, simply have a friend move their hand around the
joint while you blow. They will feel the air coming out. If you have
used a cork to plug the end instead of your hand, you can do this
yourself. Although it may be possible for someone with VERY strong
lungs to open a good key on the upper joint, I have not been able to do
so.

2. Use a similar procedure for the lower joint. This joint is a little
trickier. Most adults (at least) are able to generate enough air
pressure that they can blow open the Ab/G# pad. So you may need to use
a little less blowing force here. If and when it does open, you can
feel the change in pressure immediately. So blow with a little force
less than required to open this pad and check for any other leaks. If
that pad opens with even the slightest pressure, then it would need
replaced, reseated, regulated or possibly a new spring.

If you have not tried this procedure before, I suggest that you test it
out on a clarinet that you know to have no leaks. Then (if you can) try
it on a clarinet that does leak. The difference is air pressure is
quite noticeable.

Sometimes, but not always, you can hear a hissing sound from the leak.

Dee Hays
deerich@-----.net
Canton, SD