 The Clarinet BBoard
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Author: Blake
Date: 2001-12-03 21:00
Ive gone through the archives and didnt see anyone pose this question.... My 73' R-13 pinned in 74 with a crack between the top 2 trill keys just reopened up and split all the way to the top of the tenon and through to the bore. Is a crack like this "pinnable" realisitically or should I be considering banding instead.....or..buying a new horn. Thanks for the suggestions.
Blake
Arlington, VA
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Author: ron b
Date: 2001-12-03 21:36
Either method is acceptable, Blake. The location of the crack will likely determine whether shrink banding is practical or not. You should never, if at all avoidable, put a band into a tone hole. Nowadays, pinning is the most common as it doesn't 'show' as much (practically invisible, done correctly) and is as strong a repair as banding. It's amazing what can be done with modern adhesives and repair techniques. Your local repair tech, who will examine the instrument first hand, may offer you a choice and discuss the pros and cons for your particular situation. Since the crack goes through tone holes it's a bit more of a job, but not impossible, to make them air tight again. Only you can decide whether it's worth the cost.
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Author: Dee
Date: 2001-12-03 21:41
Given the cost of a replacement, it's probably cost effective to repair it. My daughter's oboe developed a crack that went almost the full length of the upper joint and it was successfully repaired.
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Author: john gibson
Date: 2001-12-03 22:41
Can someone explain to me just what "pinning" is? I do woodworking and have looked (at pictures) of "pins", but don't understand the process. Is it like nailing?
OR do you just "pin" the crack until the glue sets? I'm relly curious. Thanks.
John
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Author: Gordon (NZ)
Date: 2001-12-04 10:37
Blake:
When pinning, holes are drilled through the timber across the instrumen and threaded pins are then screwed through the holes, forcing their own thread in the timber to grip it and stabilize the width of the split so that filling the crack will become reliable and leak-proof. The pins are intentionally broken off just below the surface of the timber so that the holes can be filled to restore close to original appearance.
Filling a split is a separate operation carried out after the pin(s) has stabilized the timber.
Once pins are installed, even badly, they cannot be removed.
This is a very hard timber. Choosing a suitable drill size for a given pin size is quite critical and notn an exact science....
If the holes are slightly small in diameter the pins will jam while being screwed in and the pin is likely to break before it well past the crack, hence giving insufficient grip.
If the holes are slightly too large in diameter the pins do not grip adequately.
I suspect the problem with your instrument was either one of these, or as suggested in the URL above, the holes were blind and and the pins were never inserted far enough.
If there is room for more pins inserted with expertise I think your problems should be over.
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Author: Ken Shaw
Date: 2001-12-04 14:25
I've been told by too many repairers to ignore that banding should be done only as a last resort and that a band inevitably constricts the bore and thus the tone.
I have a Buffet Bb from the 1930s that has a band just above the throat A key and another one at the shoulder of the upper tenon. The sound is nice, but not very big. It responds well and is an ideal band instrument, where you don't want to stick out.
It's possible to fix even severe damage with pins. My Selmer Eb contra-alto had the bottom of the upper joint practically crushed. Steve Fox put in about 30 pins, and you can't even tell it was damaged. I strongly recommend his work, but he usually has a backlog of several months. See the sponsor's pages for his website.
Best regards.
Ken Shaw
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Author: JMcAulay
Date: 2001-12-04 15:50
Repairing a crack without pinning it is rather scary to me, unles it is a *very* minor crack. Cracking is the result of stress relief in the wood, and if you just glue it back togehter, any remaining stress may well relieve itself with another nearby crack (it won't re-crack exactly where it was glued -- modern adhesives are far stronger than the wood -- bit it certainly might crack nearby). Gordon (NZ) offers excellent information, some of which deserves emphasis and expansion. Pinning stabilizes the wood. It is an attempt to make the structure more rigid so that any residual stress in the area of the crack will not undergo further relief, thus minimizing the likelihood of further cracking. So once the wood is pinned, it is quite rigid. The filler material does not then "glue the wood together," but rather it fills the crack. The need to have pinning or, truly, *any* crack repair of consequence done by an experienced technician is emphasized by Gordon's comment: "Once pins are installed, even badly, they cannot be removed." And determining whether pins may be needed is, in itself, not a simple call. Furthermore, if pins are called for, exactly where to put them is not a decision to be made lightly. Those who have seen my posts know that I will try to fix almost anything, but crack repair -- other than something truly superficial -- is not among my repertoire. That kind of thing goes to a trusted Professional.
Ken Shaw's comment: "I've been told by too many repairers to ignore that banding should be done only as a last resort and that a band inevitably constricts the bore and thus the tone" somewhat mystifies me. It isn't that I doubt your statement, Ken, it's just that I've never held such conversations and find it difficult to understand how this could be so. I would welcome further information in this area.
Blake, I personally think you need a superior technician right now more than you need a new instrument.
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Author: David Spiegelthal
Date: 2001-12-04 20:44
Pinning only stabilizes the crack in which it is embedded --- it does nothing for the rest of the clarinet, thus there is never any guarantee that a crack won't develop elsewhere. Stress flows just like air around an object --- if it can't proceed along one path because there is an obstacle (e.g. a pin), it will flow around it. If the material nearby is strong enough nothing will happen, otherwise, another crack will form. Basic materials science.
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Author: Blake
Date: 2001-12-04 21:49
Well the word back from the shop is a recomendation that two carbon fiber bands be put on vs. 4 or 5 pins. He also didnt think the original pinning was a pinning but a filling - hard to say since I was in 8th grade 30 years ago when it was done.... I think i'm going to go with the pinning rather than two trenches around the outside wrapped in a band.. It just seems intuitive to me that banding would potentially restrict the vibration and therefore the sound and tone quality although many on the list have said over the years in the archives that the banding hasnt made a difference. I think I'm still in **shock** over the crack. Thanks to all the folks who have posted their words of wisdom. I'm reading them all carefully.
Blake Arlington, VA
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Author: Ken Shaw
Date: 2001-12-04 22:49
The advice against banding was given by Kalmen Opperman and Jimmy Yan.
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Author: Gordon (NZ)
Date: 2001-12-05 12:23
David, I agree, but hopefully the process of splitting relieves a great deal of that stress.
I sometimes put a damp rag in the bore fore a while to open the split to a presumably stress-relieved width/length before pinning, but I am conscious that if it is opened too wide, and after the pinning is done the bore dries through a period of no use and shrinks inside, then tension stresses may develop INSIDE the bore and possibly cause an internal split. Hmmm. So many factors to apply fuzzy logic to. For me pinning is about the most stressful aspect of instrument repair. There is so much adverse stuff that theoretically COULD happen.
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Author: David Spiegelthal
Date: 2001-12-05 13:49
Gordon, you make some good points there. Things are always a bit fuzzy when dealing with organic materials (wood, cane, etc.) because there's a certain amount of randomness in their structures. Not real homogeneous (and/or isotropic) like metals or plastics.
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Author: Bob
Date: 2001-12-05 21:33
Hmm.....isotropic metals and plastics!!! If you have developed a method for producing them you could become a very rich person. In my 40 plus year professional life as a metallurgist and materials engineer I saw many stress cracks in both metals and plastics. Nevertheless, I am more interested in why this instrument cracked in the first place. As I seem to recall it is quite old. If it's an old instrument one would have thought any stresses would have been relieved or turned into cracks long ago. Sentimental attachment is a good enough reason to go the repair route and my impression is that Gordon sounds like he knows what he's doing.
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Author: Blake
Date: 2001-12-06 11:23
Hind sight is always 20/20 I will probably never know why it cracked further after 30 years other than this fall i was mostly playing Eb Sop on the DeMeij "Lord of the Rings" and not playing the Bb except for a few pieces, and we've had a very dry fall in DC coupled with my playing only the Bb the past couple weeks for our xmas concert.. might have been the dryness and sudden increased playing. Dale's Music in Silver Spring is pinning it for me. I decided to go with that rather than the 2 carbon fiber bands. The price wasnt that much different. In the meantime, i'm making due with my marching B-12 and using my Fobes mouthpiece on it. I can actually make some pretty good sounds on it.. well good enough for xmas music LOL Thanks for all the advice. Blake
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