Klarinet Archive - Posting 000092.txt from 2004/01

From: mginesi@-----.net
Subj: Re: [kl] Cracks, cracks
Date: Sat, 3 Jan 2004 21:36:47 -0500

i have always used very small diameter threaded rods for crack repair. with
the advent of 'super glues', this addition to the process helps recreate
a 'healed' portion of the wound...much like calcium deposits in the area of a
bone break...but a rod is essential for lasting repair.

remember grenadilla [and rosewood and ebony]cellular structure contain an oil
[part of its marelous properties] that helps to preserve and protect the
wood. it will also in due time diminish the holding power of superglue to the
interior crack walls. one may or may not experience a recracking in the same
area. it is possible for the clarinet to be abused, or quite simply handled
well and still crack in an area adjacent to the previous repair. [not
unusual] a threaded rods installed in proper fashion [ at an angle of approx
45 degrees to the bore line and in opposition to each other i.e. /]
will reduce the possibility of this occurance.

the nature of wood is that it will expand and contract - it will
breathe...be it in a clarinet an oboe or a violin...the inherent qualities of
each species of wood is special and can be utilized for instruments by virtue
of those qualities...
as for clarinets...we all know better than to take our instruments from hot
to cold/cold to hot withput preparations and care. one should never assebble
the clarinet with loose tenon rings as contraction has occured...the
instrument must be warmed to the ambient temperature for prudent assembly.

the cellular structure of the wood used for stringed instruments is quite
different from clarinet and oboes. different densities, etc ...the resonance
properties are different and not intended to be similar. the instruments
resonate in dissimilar fashion. the body of the violin, viola, cello, etc
will vibrate as strings are played. The top, especially will vibrate with a
characteristic patterns in specific areas of the face developing for each
individual tone played. these vibrations excite the air within the body and
help to project the sound.

in the clarinet. the vibration of the reed excites the air within the air
bore. the vibration of the body is secondary. many of you know the remainder
of the sound travel.

if the crack is large and has expanded the bore of the clarinet and it is not
reduced...intonation problems can develop. many minute cracks do not distort
the bore [initially] so this may not present itself. one of the reasons hans
moennig steamed the wood to close a crack was to restore the inner bore; the
diameter, the surface, etc. pinning then closes all gaps. [however the
adjacent areas may then still display inevitable weaknesses.]

one relatively successful method;
super glue to the interior of a crack...closure of a interior surface area
[via a light clamping], pinning with at least two pins; exterior application
of glue and fine grenadilla dust will make an effective repair and will be
viturally undetectable if done well.
this works for small cracks - not through a tone hole. [this is another
process as well]

knowing this group but for a short time... there will be many that not only
disagree but have totally opposite points of view in this matter...
this is good if something positive results for the clarinetist with the
cracked instrument!

michael
> Some interesting and good replies on this cracking subject. I still am curious
> about the gluing of cracked stringed instruments though. Are there less
> opposing forces at work? Is it a more stable crack on a violin? I highly doubt
> it. Why have glues been used exclusively for this purpose? I would think
> fixing a crack on a violin, when the crack is almost always through the body
> completely would be more sensitive to expansion/contraction. I never said
> gluing was the end all be all for clarinet crack repair. If the crack gets
> bigger or open, I will surely get it pinned.
>
> As to Tony's post, if the crack is on the surface and NOT into the bore... how
> is the bore affected by the crack? I do not know. A bore could easily warp
> without ever cracking as well. Until there are plenty of facts, not opinions
> abound about this topic, I don't appreciate being told I "do not know what I
> speak of". I am just comparing ideas and gathering facts for an interesting
> topic. Well, interesting to me anyway! :) BTW... I never said because the
> reapair "looks pretty' that it was a great repair job. That would be foolish.
> So don't put those words in my mouth either, please. It was a good job from
> what I can tell... and time tells all. I had a couple clarinets with pins that
> opened up and recracked elsewhere. Maybe I have the death touch for cracking.
> lol I do take all necessary precautions to avoid it in case anyone is
> wondering.
>
> I'd love to get some pro repair guys and gals in on this topic to see what they
> use for cracks. The most reliable sources would be ones who have worked on
> countless clarinets. They could speak of results. No opinions, just facts.
>
> Frank
>
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