Klarinet Archive - Posting 000112.txt from 2004/01

From: "Steve Fowler" <steve@-----.com>
Subj: Re: [kl] Cracks, cracks
Date: Sun, 4 Jan 2004 12:14:25 -0500

Dear Frank.

Actually the glue used to repair a cracked violin is hide glue, the same
that is used in its construction. It is used in construction because it is
a very light and easily broken glue allowing for the instrument to be
taken apart by sliding a pallet knife through the seam. To repair a crack
in a violin top, either a filler piece of matching wood is glued into the
crack or the crack is closed using clamps. In both cases, small blocks of
wood are glued with the grain running opposite the top for added strength.
The top may then be adjusted by removal of material to account for the
extra weight of the blocks.

Does this sound like something that could be done to a clarinet, or even
should be?

You are talking about two completely different instruments. Two completely
different worlds and two completely different repairs. A crack in a brass
instrument is repaired by soldering a patch over the crack. Should we try
that?

For years, there have been two schools of thought on repairing clarinet
cracks. One that was supported by Selmer and others involved shrinking a
nickel or silver ring into a slot cut into the clarinet body by using a 1
ton or larger press and forcing the crack to close. The crack all but
disappeared. However, this left the bore with a reduction where the ring
squeezed the wood that many of us feel affects the sound and intonation.
It also left (IMHO) an unsightly, foreign metal ring on the surface of the
instrument advertising to the entire world that your instrument was
cracked and therefore inferior. No longer pure... not a virgin anymore...

The second accepted method is pinning. This process involves 1) cleaning
out all of the pitch in the crack by forcing MEK or other solvents into
the crack under high air pressure. 2) Allowing or forcing the crack to
close. 3) Inserting pins (usually red hot!) at angles to the crack and to
each other (/ ). 4) Filling the crack with a combination of wood dust and
CA glue. 5) Finishing the pin holes and crack to make the repair as
invisible as possible.

A third method coming into its own is a combination of the two. First the
crack is cleaned as above and allowed to close. The crack is glued and
filled as in pinning. Then a slight slot is cut into the outside of the
clarinet body and threads of carbon fiber are glued into the slot. The
rest of the slot is filled and cleaned up. Carbon fiber strands are many
times stronger than nickel or silver bands and yet do not squeeze the bore
the way flush banding does.

You see, the world of repair is in fact moving on into the 21st century
and CA glues are an important part of it. Many of us have been using CA
glues since their inception back in the late 70's or early 80's. I have
repaired many, many clarinets using nothing but CA and dust, but in all
cases where the crack has even gone 1/2 way to the bore, I pin.

I hope this helps you understand the subject a little better.

Steve

******** Fowler Music Service ********
- Custom Band Instrument Repair -
***** Plating in Silver and Gold *****
602 Kent Avenue
Pasadena, MD 21122
410.647.9537
www.fowlermusic.com

> 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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