Klarinet Archive - Posting 000638.txt from 2001/04

From: "CLARK FOBES " <reedman@-----.com>
Subj: [kl] Superglue and Beeswax
Date: Thu, 26 Apr 2001 10:33:06 -0400

Don,

You misunderstood me. In the case of Lori's clarinet she had not used any
superglue yet, but filled the new crack with beeswax. The wax will now
inhibit the superglue from
binding to the wood.

Beeswax is a good agent for filling fine cracks through tone holes because
it does move with the wood. It is a mistake to fill any crack with material
unless the crack has been allowed to close and has been stabilized (with
pins IMO). When cracks first appear they can be very fine or in some cases
very wide. Generally (not always), the large cracks will close if the
clarinet is not played for a few days. It is always a good idea to stop
playing a cracked clarinet as soon as it cracks and let it sit for a few
days. Putting any type of material in a wide open crack acts like a wedge
and prevents the crack from ever closing completely. Pins do not usually
draw a crack closed and that is not the intent. Once a crack has closed,
pins will prevent the crack from opening again under stress.

Cracks occur because of different expansion rates at the bore and the
surface of the clarinet. The most common cause of cracks is a blast of warm
air (breath) inot the bore when the instrument is extremely cold. The
outside cannot expand as fast as the inside and the instrument will crack at
it weakest point. This is usually between the top two trill keys.

In Lori's case , I suspect the dry climate may have something to do with her
wood failure. I suspect that the lack of ambient humidity in Santa Fe causes
wood instruments to dry out on the surface. The bore is constantly
humidified by the breath and most likely a similar pressure is exerted from
the inside out as in the case of the warm breath/cold clarinet scenario.
Usually these types of cracks are more severe and will not close unless the
the outside of the instrument can be rehydrated. I have had some success
with putting a cracked joint in a zip loc baggy with a violin dampit. This
should be done with a damp - not wet- dampit and given at least a week to
work.

The third type of common failure in wood clarinets is caused by too much
moisture. Very often new clarinets do not have properly fitted tenon joints.
New clarinets are also susceptible to swelling from moisture and the easist
way for moisture to enter the wood is through the end grain at the top of
the upper joint.. A tight barrel on a new clarinet that has been overplayed
can cause a crak in the upper joint. This crack usually occurs from the
register pip up to the top tenon.

Hope that helps. I guess I should write an article on my method of crack
repair.

Clark

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