 The Clarinet BBoard
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Author: Carol
Date: 2002-07-23 03:33
I recently obtained a wood clarinet with a small crack beginning to appear on the bell. The crack begins in the upper part of the bell, just inside the tenon socket, and runs for about 1.5 inches vertical, down the inside and outside of the bell. It is a small hairline crack, somewhat hard to see, but not causing any problems.
My questions is, do I just leave it alone and see if it gets bigger, or should I have it repaired? The bell seems to fit fine inside the tenon, not too tight and not too loose.
Thanks for your help.
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Author: ron b
Date: 2002-07-23 05:17
Hi, Carol
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*** This coupon good for one old goat's opinion :] ***
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A hairline in the bell, if it doesn't go all the way through, isn't critical. If it were my instrument and, as you explain, it's causing no problem I'd leave it alone. Or, if you're anxious about it you could have it pinned and relieve your concern. That's pretty much what you were thinking anyway, no? Looks like the tenon fit is okay; nothing there to be alarmed about.
I think I hear a few more cyber-coupons rustling out there.
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Author: Terry Horlick
Date: 2002-07-23 07:10
Carol,
FWIW I play on a 1925 Bb Buffet Full Boehm. I found the horn at a swap meet and had it fully restored by an excellent technician. The barrel had been amateurishly turned too short to use so I got a nice Chaddish barrel. The horn has a short and highly flared bell, shorter than a stock bell. The bell also has a crack through it at the socket and running a little way down (about 1.25").
The tech said it is not repairable... you evidently cannot pin a bell. The bell would require replacement with a custom hand turned piece of grenadilla! We tried some off the shelf bells and not only did they affect the lowest notes intonation, it seemed to change the sound a bit.
I have done woodworking and do not relish having to turn a bell on my lathe or pay to have one turned. So we opted for curtain #2. The tech flowed a little cyanoacrylate cement ("Super Glue") into the crack and then sanded the cork on the lower tennon so the fit is as loose as we dared make it. The ring helps to re-inforce the bell, the bell never gets wet, and I handle it carefully.
Now after a full year of use there is no change in the crack. I recommend sanding down your bottom <B><font color="red">cork only</font></B> for a looser fit. Be careful not to sand on the wood of the clarinet. Alternatively you can ask for your technician to loosen the fit of the lower cork. I recommend this approach as it does not further weaken the bell by cutting it's socket looser and if you get a new bell it is easy to replace that bottom cork to get back to where you started.
Be sure to swab out that bell each time you play!
The above is the experience and advice of a dentist and 37 year clarinet player, not a professional player, nor repair tech. I do have an engineering degree and some engineering experience, however. So take it FWIW, TH
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Author: Fred
Date: 2002-07-23 11:20
I have had a cracked bell repaired most satisfactorily. It was not pinned; rather, an adhesive material mixed with grenadilla(sp?) dust was used. Results? I'd probably have to show you where it was repaired, and then you'd have to take my word for it.
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Author: David Dow
Date: 2002-07-23 12:28
DEar Carol: Although this may not cause problems at the moment, you should probably have it pinned. Cracks tend to be more preveland in the winter months yet with humidty and climate change can tend to grow. Sincerely David Dow
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Author: Vytas
Date: 2002-07-23 14:31
You CAN NOT pin the bell or barrel when the crack is inside the tenon socket. Period! There are a lot of ways to repair the crack without pinning......V
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Author: Bob
Date: 2002-07-23 14:56
Carol: although you didn't say so, I am assuming the horn you secured is used. If it is an older horn the crack might have existed for a long time as it is now. Just remember...they never pinned the Liberty Bell!! and: "If it ain't broke, don't fix it".
I,myself, would wait and see what happens before I even thought of making any repair attempt.
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Author: ken
Date: 2002-07-23 15:49
If you feel you must keep the bell for whatever reason and continue playing on it I'd deal with it now and pay the $30-40 to get it "filled" by a reputable repairman...the crack's already deep enough that it's gone through. Over time, the more you play the more you increase the probability the crack will widen and extend even farther to the point it's useless...rings loose and falling off, etc. Another thing, I wouldn't recommend getting cute and sand down the cork on the lower joint...the last thing you want is slick, worn cork. With the wood constantly expanding and contracting with environment/playing conditions the bell could cease holding at all and/or eventually start falling off in the middle of play. Then you'll just add to your expense having to get the cork replaced plus repairing the crack, money you could've used to get a new one in the first place.
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Author: Ken Shaw
Date: 2002-07-23 18:43
The Liberty Bell was repaired and recast several times and cracked each time. Apparently the problem was the wrong mix of metals. See http://www.ushistory.org/libertybell/.
When Peter Spriggs restored the 1908 Buffet set I got on eBay, he found a 3" crack in the bell of the A, extending to the top of the socket. He told me the same thing -- that a bell can't be pinned, because it's not thick enough. He used super-glue, and I've had no trouble, but I'm careful to keep the moisture level up and the tenon ring snug.
Best regards.
Ken Shaw
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Author: Gordon (NZ)
Date: 2002-07-23 23:43
The advantage in doing it sooner rather than later is that the current best approach (superglue, maybe with timber dust as filler) will not work so well after you have gradually filled the crack with grease and grime.
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Author: diz
Date: 2002-07-24 00:24
Pardon my abundant ignorance - but would it be simpler to buy a new bell?
Don't BITE - this is an honest question from an honestly perplexed chappy.
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Author: Gordon (NZ)
Date: 2002-07-24 04:37
They're not cheap, they differ widely in makes and models, especially the fit of the tenon, and a reliable and close-to-invisible repair job is probably quicker to do than the task (likely unsuccessful of tracking down a replacement that fits (mechanically and acoustically) and visually matches.
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Author: JMcAulay
Date: 2002-07-24 05:28
Q:
Why in the Sam Hill doesn't someone just give that bell a good soaking with one of The Doctor's fine oils to simply expand the wood until the crack is *really* invisible? And then oil it a bit now and then to keep it from drying?
And while I'm fairly certain no one gives a hoot, I do not believe I would *ever* pin a bell.
Regards,
John
Eagerly awaiting GBK's comment that if the Liberty Bell yoke had been grenadilla instead of slippery elm, they'd never have had a problem with a cracked bell. :þ
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Author: GBK
Date: 2002-07-24 06:50
Everyone knows that to correctly break in a new Liberty Bell - PLAY ONLY 15 MINUTES PER DAY FOR THE FIRST WEEK.
...GBK
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Author: Gordon (NZ)
Date: 2002-07-24 13:16
Unless I'm mistaken.....
When a tubular item expands evenly, a crack on the outside does not shrink to invisibility; it gets slightly wider.
To make the crack shrink to invisibility one would have to expand the outside of the tube without expanding the inside.
This could be done by introducing moisture to the outside but not the inside - rather difficult - or by shrinking the inside but not the outside.
The crack has probably resulted from the stresses that existed in the particular piece of timber - stresses that were always there. When the timber cracks the stresses are relieved (somewhat). To close the crack one would have to re-introduce the stresses.
As far as I know techicians agree about not pinning a bell, mainly because the walls are too thin.
A groove could be turned and then filled with carbon fibre fillament with epoxy or CA glue, to restore strength to a tenon socket.
There is a method of repairing castings, such as bells, with a process called 'stitching', which is effectively the same as pinning a clarinet split, but using welded or brazed 'beads' across then split instead of pins. Perhaps it is acoustically unsuitable for bells.
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Author: Bob
Date: 2002-07-24 15:07
Internal stresses in materials can reach very high levels. I was once in a shop that was working on parts for Caterpillar tractors. All of a sudden there was a loud explosion and a part that was simply resting on a bench exploded and sent shrapnell that embedded into the concrete walls. Gordon raises a good point that closing an existing crack(by pinning!) can simply reintroduce stresses elsewhere in the bell wall. His "groove/filament" solution makes sense to me. Cracks in some wood products have been known to exist for years without impairing the functionality of the parts involved
while others grow and the part fails. Go figure.
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Author: David Spiegelthal
Date: 2002-07-24 17:46
I hate it when those clarinet bells explode and send grenadilla shrapnel flying through my basement..............
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Author: Carol
Date: 2002-07-25 04:38
I placed some bore oil over the crack and let it sit overnight. It seemed to make a difference. The crack did start to close in, but not completely. The crack can still be seen, but it is much tighter and now looks more like a scratch. Fortunately the bell has not exploded...yet!
I really appreciate all the responses.
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Author: Terry Horlick
Date: 2002-07-25 05:29
Bob wrote: "Just remember...they never pinned the Liberty Bell!!"
With all due respect, Bob, pinning (well actually I guess it was riveting, but they called the repair pinning) was one of the first things they tried to try and stop this bell from getting worse. Here, I will post a photo for you...
<center><Img src="http://pages.sbcglobal.net/thorlick/images/lb.jpg">
I have recently started doing some sand casting of aluminum, brass and bronze. It is really a feat to cast a bell, especially more than 200 years ago. You try to heat a pot of ore weighing over a ton to around 2,400 degrees F and then pouring into a mould in sand made by hand by digging a hole into the ground and filling it with sand! It is really amazing that there are bells which haven't broken.
All this said, what in the world does the Liberty Bell or any other Bronze bell have to do with our lovely wooden clarinets? I'm confused about that!
Terry Horlick
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Author: Gordon (NZ)
Date: 2002-07-25 06:28
Oiling a crack to imagine it might close and even remain closed.... This pretty well blows any chance reliability from a repair that depends on an adhesive sticking.
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Author: Bob
Date: 2002-07-25 15:06
Terry..I bow to your research and your metallurgical expertise... in all seriousness. But I don't understand why you would be confused about my serendipitous associations.
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Author: JMcAulay
Date: 2002-07-27 03:37
Actually, Gordon, i never oiled a crack to *imagine* anything. However, several years ago I soaked a cracked bell (in Olive oil, before The Doctor made me wiser) and the crack viortually disappeared. And the bottom notes worked. Which is to me the primary consideration. If the instrument works, it's fixed Will it work until the year 2,312? Your guess may be better than mine. What the heck. By then, it may be blown out. Heheheheh
Regards,
John
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