 The Clarinet BBoard
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Author: gigaday
Date: 2014-04-15 15:21
I have a 60 year old B&H Regent which I have played for 10 years. It is generally in good condition and plays well enough for my playing standard.
It has had cracks ever since it was manufactured, as far as I can tell, at least one has a pin in it and I am sure that the one previous owner would not have had it repaired. The cracks seem to come and go with the seasons, sometimes opening up and sometimes disappearing almost altogether. With the coming of Spring this year there seem to be a couple of new ones. They are not very big and the instrument still plays as it always has.
I wondered about the possibility of binding the cracks to stop them growing and experimented by clamping the crack at the end of one of the joints to see if I could close it. I used a reasonable but not excessive amount of clamping force and the crack did not close at all - I didn't want to overdo it and do extra damage.
Do people think I should just leave it as it is and carry on playing until something terminal happens? Or it there anything that would be worth doing to halt the progress of the cracking?
Tony
Post Edited (2014-04-24 15:06)
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Author: cyclopathic
Date: 2014-04-15 15:53
are those bore cracks or outside?
On instruments like this I usually superglue cracks when they open, and then oil body in/out with bore oil. Oiling restores wood; it swells a little so some of the smaller cracks may disappear, and makes wood less susceptible to season changes. Just keep in mind that after oiling glue will not adhere, so it is essential to get it done prior.
It is hard to say if banding is need w/o looking. If you post pics perhaps Chris P could comment he had some pics of carbon bands posted in the past, and the work looks really top notch.
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Author: gigaday
Date: 2014-04-15 16:02
The cracks are on the outside and don't go into the bore. I did try superglue on them and although it made them disappear for a while I think it must have fallen out with the expansion and contraction and they reappeared.
I have kept oiling to a minimum.
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Author: Caroline Smale
Date: 2014-04-15 22:30
For the wood to still be moving after 60 years is very surprising, it must just be a naturally unstable piece of wood. I don't believe superglue will really hold that sort of cracking (and after 60 years it will be virtually impossible to clean out most of those cracks well enough anyway.
Banding is probably the only effective way on wood like this as pinning one crack will just move the stress somewhere else.
However if the cracks haven't reached the bore after 60 years you are probably safe to just carry on playing it (and replacement old Regents are very cheap these days).
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Author: gigaday
Date: 2014-04-16 00:34
Norman
I think you are right, the cracks aren't worth worrying about unless the instrument stops playing, in which case I will have to get another one. :-)
One just gets attached to the old familiar friends - well I do.
Tony
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Author: Gordon (NZ)
Date: 2014-04-18 18:55
Cracks are of concern when the produce a leak by going into a tone hole, or are spreading with a strong possibility of doing that that, or go through to the bore creating a leak. It is then that increased stabilisation using (rather obsolete) flush-banding for which few technicians have the gear, or carbon fiber and filler in a milled groove, or pinning should be considered.
Alcohol is not a good solvent for de-oiling the surfaces where the glue will wick. And it makes a huge mess of the black paint/grain-filler used on some timber surfaces, especially the timber of cheaper models where substandard timber has been used. Lighter fluid is far better. Repeatedly wick it into the crack and blast it out with compressed air.
After that, superglue has an excellent chance of holding. But it must be a very low viscosity superglue so that it wicks to the bottom of the crack. And it needs to be done with care because it makes a total mess of some timber finishes. Most of the work is in the cosmetics of the finish.
But for wider cracks superglue is a poor filler. So use either grenadilla dust in conjunction with superglue (with appropriate technique) or slow-setting epoxy (with back pigment powder mixed in?), forced hard into the crack. (I force it in with a finger covered with a finger cot or finger from a surgical glove.)
Post Edited (2014-04-18 18:57)
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Author: cyclopathic
Date: 2014-04-18 21:52
@Gordon: IMHO grenadilla saw dust and superglue is the best for big fills, but you probably have to do it repeatedly 2-3 times to get a good result.
@OP: cleaning prior to gluing and then making final product look good are the biggest challenges good luck
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Author: Gordon (NZ)
Date: 2014-04-19 18:02
"have to do it repeatedly 2-3 times to get a good result."
If you mean alternating the two materials to build up from the bottom of the crack, then I agree.
I have used both superglue/grenadilla dust and epoxy as split fillers/stabilisers with no failures to my knowledge, so I currently cannot say one is better than the other.
Superglue is certainly very quick to use, but is capable of doing a lot more cosmetic damage to certain timber finishes.
Although there is a huge range of superglues and epoxies, for the ones I have used, superglue seems to set quite a bit more brittle than epoxy does, but I am not sure that that matters in this application.
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Author: BobD
Date: 2014-04-19 19:12
If the wood needs to move for whatever reason then stabilizing an existing crack could lead to new cracking elsewhere. Yes, No, Maybe?
Bob Draznik
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Author: cyclopathic
Date: 2014-04-20 15:23
BobD wrote:
> If the wood needs to move for whatever reason then stabilizing
> an existing crack could lead to new cracking elsewhere. Yes,
> No, Maybe?
>
it is either YES or Maybe. It depends on if you just do gluing only or you also do oiling/waxing. With exception of mechanical damage almost all cracks are either to barrel or to the top of the top joint; the part of clarinet which gets the most exposure to condensation. Oiling reduces stress to dried wood, and waxing reduces the moisture content swings, so there is less chance of cracking. Also oiling may close many smaller crack and make bigger cracks smaller.
But in general if one crack glued but the wood needs to move stress has to go somewhere else.
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Author: Gordon (NZ)
Date: 2014-04-20 18:23
A crack de-stresses timber. So I always do what I do while the crack is open.
But yes, making one part more rigid, say by pinning, in theory places more stress on another part if further stresses are induced. And this may lead to further cracks in the vicinity.
In practice, I have never experienced this happening. Perhaps the stress relief from the crack being open, is sufficient relief in the vicinity for future stresses not to build up high enough to result in further cracking.
BTW, a pin crosses a crack quite close to the bore, and would stabilise the timber there. However I believe that a pin probably does rather little to stabilise the width of a crack near the outside of the crack. A good adhesive filler is probably largely responsible for stabilisation near the surface of the timber.
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Author: cyclopathic
Date: 2014-04-20 19:22
^^
it almost sounds as discussion on San-Andreas fault (or whatever NZ equivalent, Alpine?)
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Author: cyclopathic
Date: 2014-04-21 17:17
Gordon (NZ) wrote:
> BTW, a pin crosses a crack quite close to the bore, and would stabilise the
> timber there. However I believe that a pin probably does rather little to
> stabilise the width of a crack near the outside of the crack.
this is very true. I had to glue a couple very good pins which looked like they were made at the factory (one was made prior to polishing/post fitting, another one had a cap out of the matching wood). Wood was still moving 40-70 years later.
Pins are certainly easier to execute as you don't need lathe to cut the groove, but for big cracks bands are better choice, IMHO
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Author: fskelley
Date: 2014-04-21 18:00
cyclopathic, are you saying some new instruments might have hidden repaired cracks? Is this common? Would it be disclosed? Do they matter? Should you get a new (or used) instrument x-rayed or ultrasounded?
Stan in Orlando
EWI 4000S with modifications
Post Edited (2014-04-21 18:01)
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Author: cyclopathic
Date: 2014-04-22 05:15
@Stan
I had worked on 2 but not new, they were ~40-70y.o. Not sure how common this could have been back then; probably not, and not now on new modern instruments. Someone who works in retail would have a better idea.
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Author: Gordon (NZ)
Date: 2014-04-22 05:45
cyclopathic wrote : ".... for big cracks bands are better choice"
They have their own problems. Compared with timber, metal (or probably even carbon fibre bands) they are far more rigid.
As an aside, for most materials, if a cylindrical shape is made to expand, then the inside diameter gets larger as well as the outside diameter. I'm not so sure this is true of timber.
So if the outside diameter of the timber, i.e. diameter beneath the band tries to expand but cannot, I suspect that for timber, the inside diameter, i.e. the bore, reduces. This may affect the way the clarinet plays.
What may be of more concern is that as the timber dries out it tries shrink. So so the outside diameter, i.e. beneath the band, must shrink away from the band. So the band is no longer offering any support to the underlying timber.
In that state, if the bore suddenly becomes damp again and expands, then the outside diameter, still dry and no longer supported by the band, must be just as likely to split as if the band were not there.
Another thing that I cannot get my head around is that when bands are squeezed into a groove, and the pressure is then removed from the press, the metal must "relax" a little, resulting in very little support of the timber from the band. On the other hand, if the band was squeezed tighter to allow for this - guesswork - while it is being installed, then that would risk internal timber splits, emanating from the base of the groove.
In summary, there are numerous issues when we have two materials with very different expansion/contraction properties, and expect them to move together we can expect issues. This is known no better than to dentists and dental technicians bonding materials to teeth, or crowning them. such professionals have to match coefficients of expansion (in this case, I guess, largely thermal)
Add to that, metal bands look ghastly.
The alternative banding, using carbon fibre in black epoxy (or superglue with timber dust filler) Probably has less of the above issues and is better cosmetically. (Personally I think pinning is by far the best cosmetically.)
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Author: cyclopathic
Date: 2014-04-22 14:56
@Gordon
it is interesting discussion.. I suppose I just had limited exposure to banding and never seen one to fail. Bands certainly look as more work then pins, but then pins are more work then gluing, and if glue works...
Either way the root problem is timber instability. Not per say clarinet related but here is an interesting read on stabilizing wood: http://www.woodturningvideosplus.com/wax-emulsion.html
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Author: BobD
Date: 2014-04-22 19:56
There was an interesting procedure used on bowling pins some years ago in which the pins were put in a vacuum chamber and the entrapped air removed. Then the chamber was flooded with a plastic material that was cured somehow. It's possible that some who are new here may think that the purpose of pinning is to squeeze the crack shut.
Bob Draznik
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Author: Tony F
Date: 2014-04-22 20:26
A company near here uses the same technique on wood parquet floor tiles, stabilizes them and makes them incredibly hardwearing. I've though about trying it with oil to see if I could get more complete oiling.
Tony F.
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Author: cyclopathic
Date: 2014-04-23 16:50
@ Tony
interesting idea.. would probably work well to drive superglue deep into crack.
They are using similar technique to fill in windshield chip
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Author: Gordon (NZ)
Date: 2014-04-24 12:46
Lowest viscosity superglue wicks very well into cracks already.
And I don't know how you would introduce superglue locally while the instrument was in a vacuum.
BTW, a clarinet body saturated with oil has a range of other problems, including weight, reduced friction to hold posts in, brittlisation of pad membrane.
What is wrong with these materials for clarinet making. They make outstanding knife handles.
http://ajh-knives.com/stabwood.html
When is the last time you had a problem with one of those fancy black kitchen knife handles? They sure get abused.
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Author: Gordon (NZ)
Date: 2014-04-24 12:54
From http://www.moonrakerknives.co.uk/wkhb.html :
Stabilised woods have been impregnated with monomers and acrylics to produce a dimensionally stable wood.
Some advantages of stabilised woods are:-
- That they minimize or totally eliminate shrinking.
- Will not absorb water.
- Resist cracking.
- impervious to oils.
- Resist expanding/warping
Why didn't Buffet/Greenline use this? More expensive than Grenadilla?
Post Edited (2014-04-24 12:54)
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Author: cyclopathic
Date: 2014-04-24 15:01
Gordon (NZ) wrote:
> And I don't know how you would introduce superglue locally while the
> instrument was in a vacuum.
The simplest way would be to apply glue, put joint into vacuum and let the air escape. Glue will be forced deeper into crack when air pressure restored.
with respect to using polymers to stabilize wood, there is another example: diamonwood, popular with fretless bass manufactures. It is a maple (birch?) plywood glued with extra hard epoxy. Very nice finish, similar to "propeller wood" PanAms, but with more color choices.
My guess they would work very well. There are will be some acoustic differences attributed to material (sharpness of toneholes, smoothness of surface, mechanical properties, etc) but they would be hard to market and won't sell.
Some stereotypes are hard to break: clarinetist believe that grenadilla is the best material for clarinet, flutist believe in silver, saxophonist into french brass or bronze, etc.
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Author: Gordon (NZ)
Date: 2014-04-26 04:57
cyclopathic wrote:
> The simplest way would be to apply glue, put joint into vacuum
> and let the air escape. Glue will be forced deeper into crack
> when air pressure restored.
Surely, the superglue will be set long before the vacuum is created. In a confined space it takes only a few seconds.
Furthermore, when the vacuum is applied, the first thing that would happen is that the air would be drawn out of the timber, taking with it any adhesive that has not set.
AFAIK this process depends on creating the vacuum long enough to get air out of the timber, then making sure the timber is surrounded in the adhesive prior to encapsulating the surface prior to releasing the vacuum so that the fluid is drawn into the timber. It is a process that takes time, and imagine the entire item needs to be immersed in the adhesive at least while the pressure is being released.
Post Edited (2014-04-26 05:01)
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Author: cyclopathic
Date: 2014-04-27 15:14
@Gordon
I think it depends, some super glues take longer then a few seconds, and for the same glue time to set depends on moisture content and amount applied. The superglue I've used definitely takes more then a few seconds to set, and with amount applied I have to wait 'till next day to file it. Never the less it will be challenging, no doubt.
Where vacuum could work well is for gluing through cracks. If you are using vacuum for leak testing and the air is sipping through the crack, glue put on outside will be sucked in...
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Author: Gordon (NZ)
Date: 2014-04-27 15:38
"...Where vacuum could work well is for gluing through cracks. If you are using vacuum for leak testing and the air is sipping through the crack, glue put on outside will be sucked in..."
Hopefully not into the bore where it will be very difficult to remove.
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Author: cyclopathic
Date: 2014-04-27 18:10
Gordon (NZ) wrote:
>
> Hopefully not into the bore where it will be very difficult to
> remove.
tell me about it!
Had to work on cracked and previously patched barrel; it had been cracked completely and was very crudely glued with big clamps of glue. While it cleaned up nicely on outside, inside wasn't easy. You can't use reamer as glue too hard, and filing can do more damage.. at the end left it alone. Looks disturbing, but seems doesn't affect tone/intonation.
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Author: Tony F
Date: 2014-04-27 18:40
When I had the problem of removing glue runs from the bore of a barrel I made a scraper from a piece of brass rod brazed to the side of a steel washer slightly smaller than the bore.
I then bevelled the edge of the washer on the opposite side to the brass rod and put a scraper edge on the washer with a burnishing tool. By passing the rod through the bore and then using it as a handle to carefully pull the washer through I was able to remove the glue run without damaging the bore. I've used it several times since, it works fine. It would probably work in the bore as well with a longer handle.
Tony F.
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Author: Gordon (NZ)
Date: 2014-04-29 14:57
With superglue?
I think it is significantly harder than the timber after curing.
When scraping (or otherwise working) a hard material surrounded in softer material it is very, very easy to scrape some of the soft material.
Post Edited (2014-04-29 14:58)
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Author: Tony F
Date: 2014-04-29 16:47
Hi Gordon,
Yes, it is easy to scrape the bore, but with careful work and control of the tool and the workpiece it need not happen. Perhaps not for the fainthearted, but I've used the tool several times without removing anything that I didn't want to remove.
Tony F.
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