Klarinet Archive - Posting 000370.txt from 1998/09
From: avrahm galper <agalper@-----.com>
Subj: [kl] FINDING LEAKS
Date: Sun, 13 Sep 1998 02:18:59 -0400
Leaks are sometimes hard to find.
There may be a slight nick in the rim of the tone hole, or there may be
a porous part in the wood under the pad.
When Frank Marcus, local bassoon expert, does his work, all these things
are taken care of. The wood under the pad is impregnated with wax or
something similar. The little nicks are either filled or a new seat is
made, so there is no leak from that.
The smoke test sometimes tells you where the leak is, not necessarily by
seeing the smoke coming up but after blowing the smoke into the joint,
one runs a cigarette paper under each pad and one can usually find a
tiny leak by seeing the nicotine on the paper. Could be the pad but most
of the time it's a small nick in the wood. You might have to look at the
pad to see if there are any breaks in the skin.
Regarding the air compression test. I had one of those. It was home
made. It was glass tube sitting in a little bottle of mercury. The tube
was slanted upwards. On the other end there was a rubber tube attached
to the glass. This rubber tube was attached to a rubber stopper that had
a hole in it.
You stuck the stopper with a tube into the bottom of the clarinet
joint. You then sucked through the joint and the mercury that's in the
inclined upward tube will rise. When you stop sucking, (not to bring the
mercury too far) the mercury in the tube will fall. If it falls quickly,
then there is a big leak. If very slowly, then its gotten better.
All these things were nuisances but they had to be done if you wanted a
leakless joint.
There are others who use a light. If the pad at a particular location is
too bright, there may uneven seating of the pad. I could never do this.
I have some seen others, usually craftsmen from Europe, who can blow
across the tone hole and the pad and tell if there is a leak there.
The feeler method is pretty good for telling unevenness of seating. One
should have little snippets of cigarette paper shaped like pennants. And
try the different directions of the tone hole.
--
Avrahm Galper
THE UPBEAT BAERMANN MELODIC SCALES AND ARPEGGIOS
http://www.sneezy.org/avrahm_galper/index.html
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