Author Topic: Yikes, a crack!  (Read 2975 times)

Offline BLMonopole

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Yikes, a crack!
« on: January 13, 2013, 03:29:48 AM »
While I typically wouldn\'t stress out about a crack (as I play a couple clarinets that have repaired cracks that perform wonderfully), my prized and beloved Monopole Conservatoire has developed a hairline crack on the top of the bottom joint, starting in the socket and traveling through the first tone hole.  I can\'t think of a worse location!

The instrument still plays well, and the tenon ring will likely keep it from getting worse (at least for a while).  I dread the idea of a socket replacement or a metal socket liner at some point in the future.  

Any other ideas?  I know that it\'s not the end of the world, but for some reason I\'m pretty bummed out about it...

Offline DaveLeBlanc

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RE: Yikes, a crack!
« Reply #1 on: January 13, 2013, 05:43:10 PM »
ive heard that super glue fills in cracks nicely,...
David Watson of the original The Clarinet Pages

Offline gkern

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RE: Yikes, a crack!
« Reply #2 on: January 13, 2013, 06:31:05 PM »
This is getting as bad as the flu epidemic!  I have a post about the same thing that happened in the top joint of my PM Brilliante.  My tech guy is rebuilding the tone hole and putting in 5 pins.  $$$ no object for this horn, good thing!
Playing a clarinet badly is better than not playing a clarinet at all.

Offline Silversorcerer

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Re: Yikes, a crack!
« Reply #3 on: September 15, 2015, 09:36:28 PM »
I know this is an older thread, but I stumbled on it reviewing threads here, noticed the location of the cracks reported and realize this is one of the most common cracks to plague older clarinets.

I have had some success closing both of these types of cracks with collagen glue, which is a rather non-invasive process compared to pinning, filling, or boring out the tone hole for a sleeve insert. Collagen glue is also completely reversible and renewable. If it doesn't work, one can try again or try a more extreme remedy.

The crack in the LJ tenon to the B tone hole, one of the most common cracks I see in older clarinets, is probably not the worst to deal with because it usually is caused by a tenon cork that is too tight or gives uneven pressure within the socket. First the ounce of prevention so this doesn't happen to your other wooden clarinets:

Tenon corks have to be perfectly cylindrical and there should not be any bulging areas from the top of the tenon cork to the bottom. They should not look like footballs. So this is the first prevention is to make sure the tenon cork for that joint is a perfect fit, not a tight fit in just one area of the socket. This means taking some extra care in getting the fit right and if possible mounting the UJ into a spinning (slowly) lathe to reduce the cork diameter once a tenon cork is fitted. Using a lathe or other means of rotation will guarantee the most cylindrical shape for the tenon cork.

The next thing to be sure of and to check often is the tightness of the socket ring. The metal socket ring should never be loose on the LJ socket. It is there to prevent this type of crack. If the LJ loses moisture and shrinks, space can develop in between the ring and the socket and that space allows the tenon cork pressure to crack the socket. It will do it where the tone hole is because that is very close to the bottom of the socket and it is where the wood is weakest. If that socket ring becomes loose, you are well on your way to a crack because two things have happened. There is room for the wood to be expanded and crack, and the socket has shrunk in diameter which inevitably means a tighter fit and more pressure on the wood. If the ring becomes loose enough to turn on the socket, shim it with thin paper or tape until it is tight. I do not recommend using a permanent adhesive to secure it. Metal and wood expand and contract at different rates and for different reasons, therefore they should remain separate parts.

I keep saying it over and over again;- regularly apply bore oil to the bore of your clarinet. A little goes a long way, but not for a long time. It has to be a regular regimen. Older clarinets often have not been oiled regularly and thus need oiling more frequently when we begin playing them more regularly. The oil in the wood regulates the moisture in the wood and helps maintain dimensional stability and therefore resistance to cracking forces.

Closing the crack vs. filling the crack?

The crack was not always there. There was a condition of the wood when the crack had no space in it. This is the condition that should be restored. Filling the crack is inviting it to open back up eventually and it does not address the primary reason the crack appeared. First address the tenon cork condition and the ring tightness if these are problems. Before oiling the socket, you want to close the crack. it is a fact that wood swells when it absorbs moisture. This is how the crack can be closed permanently with only water soluble collagen glue. Hot collagen glue is brushed into the crack (I use a 000 sable) and the socket is clamped with a cork lined luthier clamp with light pressure. The combination of the water swelling the wood and the clamp holding the crack shut will close the crack. The process can take several applications because the water will migrate slowly into the wood on either side of the crack. It will carry the glue with it as it migrates and soaks in. I generally work on cracks like this for up to 2 weeks. It is best to do it in the summer when it is both hot and humid. That environment can be artificially created in a small room if need be.

The collagen glue will shrink as it dries and begin to pull the wood together. It might take a few days if this was an open crack and it is necessary to make sure that the glue is worked into the entire crack. The line of the crack should be wet at least once a day during the process. The inside of the tone hole where the crack extends should also be painted with the very dilute collagen solution. The point is to make sure that all of the crack absorbs the water and the glue and is allowed to soak it up for several hours between applications. When you can see that the crack is entirely closed, the gluing part of the process is done. Now you apply bore oil to the inside of the socket and the joint. Go ahead and oil the barrel and upper joint and bell while you are at it. Well oiled clarinets rarely crack. The oil will not displace or weaken the glue join. The collagen has solidified and is in the wood and will substantially stop the migration of the oil. The oil will seal the repair. When a few applications of oil are completed, excess glue on the wood surface can be removed by scraping it off gently. It will be adhered pretty well, so be persistent with a scraping tool. There will be usually a very tight but visible glue line. If you wish to protect the glue even more from moisture, a very dilute solution of shellac can be applied to the top of the tone hole and the interior of it. That's it. No pins, no tone hole insert.

I have repaired several cracks of this type to date, probably a half dozen at least, and these all appear to be permanent so far. They are also barely visible, about as visible as the crack was to begin with at most.

This is really not the worst crack location because once the upper joint is fitted in the socket, the tenon of the UJ will seal most of the crack. Since the crack terminates in a tone hole, it is not so likely to extend farther down. In that the socket is has a metal ring around it, there is a limit to how much pressure the tenon cork can put on the socket. Collagen glue has very high adhesion properties. In many cases, a collagen repair is stronger than the surrounding wood. It must be done properly and must be done with properly prepared flake gelatin glue. Luthier suppliers are the best place to obtain the glue. I recommend the highest gram strength available for woodwind instrument repair. I have successfully closed cracks where pinning jobs and banding jobs have failed. Super glue might work for a short time, but  I regard cyanoacrylate as a temporary repair that is permanently adhered to the wood. It does not have very high adhesion properties. It might be OK for cracks where there is no future stress on the wood, but in a socket crack case, there is going to be a tight tenon going back into it. Cyanoacrylate is not likely to withstand that pressure and once the interior of the crack is coated with cyanoacrylate, no other adhesive can penetrate the wood. The eventual result of a failed cyanoacrylate repair is a crack that has been sealed open. One can simply apply more cyanoacrylate if it fails and this results in a gradual widening of the crack each time the cyanoacrylate is applied. I know it is extensively used for hairline crack repairs, but it is worth considering where that hairline is and how much stress it will have in the future. The best medicine of course is prevention with bore oil.
- Silversorcerer (David Powell) exclusively for Phil's original “The Clarinet Pages" forum

Offline Silversorcerer

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Re: Yikes, a crack!
« Reply #4 on: September 15, 2015, 10:29:19 PM »
It hurts me to hear about a Penzel Mueller Brilliante developing a crack, but the location of the crack, which if it appeared at the top of the UJ, is very common and is typically a result of condensation absorption and loss and displacement of the oils in the wood. Penzel Mueller included a document with all of their clarinets warning that the warranty was void if the instrument was not properly and regularly given bore oil treatments. I have posted photos of that document in the past. Most people who own these second hand are not aware of it.

Typically cracks in the UJ will extend from the tenon that fits into the barrel down to the register key,  perhaps beyond it, or to the highest trill hole. This is the area where water accumulates on the end grain of the tenon, soaks in and expands the wood, displaces the oils in the wood, and when it dries out the wood shrinks to less than its' original dimension and then cracks around the register pipe. Usually we see bands applied, pins installed, etc. Later we see that these repairs ultimately fail unless the regimen of applying bore oil is properly attended to. In one case I have successfully closed a failed banding and pinned repair, in another case of this kind of crack I have successfully closed an original crack and filled the space with ebony dust. I no longer favor filling open cracks having found now that these can usually be closed completely by swelling the wood with very diluted collagen glue while the crack is simultaneously under clamping pressure with cork lined luthier clamps.

Such a crack will of course render an instrument nearly unplayable. Sealing it will restore the instrument to its' original playability. I have used collagen glue alone to make this type of repair, which if not permanent, is reversible and renewable. In general, it appears to be permanent so far. The method is similar to that outlined above, and soon I will post several examples of both types of repairs, some more complex than others, but all using nothing but clamps and hot dilute collagen glue of 400+ gram strength. 

Once again, an ounce of bore oil (actually much less), or an ounce of prevention, is worth a pound of cure;- but it only takes about a 1/4 teaspoon of collagen flakes in water and a good bit of care and patience to achieve the pound of cure.
- Silversorcerer (David Powell) exclusively for Phil's original “The Clarinet Pages" forum

Offline Airflyte

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Re: Yikes, a crack!
« Reply #5 on: May 25, 2020, 12:57:25 PM »
Reviving this to prevent unnecessary new posts  :D

My question is . . . . does a small "hairline" crack automatically mean a leak?  I can post a pic but just can't imagine any air getting through it as it is.
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Offline DaveLeBlanc

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Re: Yikes, a crack!
« Reply #6 on: May 25, 2020, 01:30:48 PM »
Not in my experience. It takes something very severe to go all the way through. The majority of cracks you’ll see are surface cracks that can be filled in easily with grenadilla dust and super glue.

Only the through the bore ones leak and need to be pinned.
David Watson of the original The Clarinet Pages

Offline BLMonopole

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Re: Yikes, a crack!
« Reply #7 on: May 26, 2020, 09:37:41 AM »
Dave is absolutely right.  The crack that formed back in 2013 is still there on the instrument.  It's held in place by the metal ring, and I have reinforced it with some superglue. The crack hasn't budged, the instrument is still great and playable, and I had even forgotten about the crack until this post was resurrected.

I will say, however, that these kinds of cracks do impact resale price.  But on a Monopole Conservatoire, its not like it's a booming market anyway (it should be, but it isn't.  LOL)
« Last Edit: May 27, 2020, 11:32:30 AM by BLMonopole »

Offline DaveLeBlanc

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Re: Yikes, a crack!
« Reply #8 on: May 26, 2020, 10:34:28 AM »
To test for a leak, you can submerge the piece in water and blow air through it. If you see any bubbles rising then there’s definitely a leak. If not, then no leak.
David Watson of the original The Clarinet Pages

Offline windydankoff

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Re: Yikes, a crack!
« Reply #9 on: May 27, 2020, 01:54:54 PM »
I have great results locating leaks using a modified stethoscope, described here:
http://clarinetpages.info/smf/index.php/topic,1673.msg12507.html#msg12507
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