 The Clarinet BBoard
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Author: Kalashnikirby
Date: 2017-11-05 18:27
There's something I've noticed about changing this cork which some people find very difficult and what I install using super strong double sided tape (lol!)
At least with the main brands, Buffet and Yamaha, using 1.5mm plates works like a charm with practically no sanding required.
Impractically, it's almost impossible to fit a barrel without the cork sliding away, as it's never been compressend before. I did flatten it one time before installing it, which seems to work fine. Not sure if this is the best solution, though, because it makes the cork curl upwards.
Wouldn't it make sense to use some kind of clamp once it's glued to the tenon? Fresh cork that can still expand a little just makes for such a beautiful, tight connection that I would like to avoid sanding it down, unless the joints can't be disassembled without force.
BTW the only cork pads available here come from Pisoni or Stölzel.
Both seem to be slightly softer, but of better quality than what Buffet uses, as the texture is more homogeneous.
Post Edited (2017-11-05 18:28)
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Author: kdk ★2017
Date: 2017-11-05 18:59
Kalashnikirby wrote:
> There's something I've noticed about changing this cork which
> some people find very difficult and what I install using super
> strong double sided tape (lol!)
I can't tell with your addition of "lol!" whether this is some kind of tongue-in-cheek comment or you really do use "super strong double sided tape." If you actually use tape for this, what brand is it? I use contact cement for corks, but would have a number of other uses for double sided tape that doesn't loosen easily or get mushy when wet.
Karl
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Author: Kalashnikirby
Date: 2017-11-05 19:56
Karl, I actually do
It's just hillarious (in a pleasant way) that this actually works very well . I was inspired by Buffet, who seem to produce their tenon corks with tape on them already.
https://www.3m.com/3M/en_US/company-us/all-3m-products/~/3M-Double-Coated-Tape-9448HK?N=5002385+3294000720&rt=rud
Initially, I got this for smartphone repairs I do, but it's so far the strongest stuff I ever had, do not compare it with carpet tape and the like. 3M offers a plethora of different tapes that might suit this application even better, but I'm already happy with what I have. As it has superb adhesion on smooth surfaces, using it for keys etc. shouldn't be a problem. You know what, maybe ill try it for my Bb trill key!
Best regards
Christian
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Author: Caroline Smale
Date: 2017-11-06 01:07
For some years double sided tape was used on some student brands to fix key corks.
Unfortunately that proved to fail very easily under warm conditions and corks slipped and came loose.
It obviously offers a quick and cheap solution for manufacturers but most technicians prefer to use contact cement for a long and permanent job.
Also with contact cement there is no need to clamp the cork onto the tenon.
pre-compressing the cork before applying to the tenon can help if the cork quality is a little substandard.
Sometimes one can be lucky and find that the cork needs no sanding after fitting however sanding the cork after fitting to the tenon to obtain the optimum fit is a standard technique for any good repairer.
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Author: Matt74
Date: 2017-11-06 02:14
I do some computer repair, mostly laptops (A+ certified). I always try to do the job right, use the right parts, and make things look like I never touched them. Doing it like a pro is satisfying. The same goes for woodwind repair. People do things different ways, but for corks rubber cement or shellac is the only way to go.
It takes practice. I don’t have any nice clarinets right now, but pictures of some of my corks are attached. I’m getting better. If the corks are fitted right you can assemble the horn with no cork grease. Leave them dry overnight first.
One problem with trying to use tape on tenons is that you would get a leak. The edges won’t overlap. It might be difficult to tell at first, but over time the seam will wear and open up.
Support your local instrument tech! Tenon cork replacement is a good way to try them out. A good tech will take pride in the job. It will look and seal great.
This is great:
https://youtu.be/WOXEG56QUgY
- Matthew Simington
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Author: Kalashnikirby
Date: 2017-11-06 03:41
Matthew,
My struggle to find OEM or at least decent quality parts along with refurbishing original LCDs will never end, so I know what you mean.
But firstly, the tape worked fine for me. Contact cement is neither expensive nor am I afraid to use it, I just tend to look for simpler solutions. Secondly, the tape I use is different and I don't see why I shouldn't use it if it works. Thirdly, this wasn't point of my thread... Also, the tenon corks on my clarinet I swapped myself are good.
Caroline,
from my experience there's pretty much one kind of quality commercially available in Germany, and if I don't compress that cork a bit, the fit later will be rather wobbly.
My RC did have synthetic cork held in place with tape, which didn't adhere too well, but still lasted for years. There are certainly more durable adhesives for that purpose.
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Author: Chris P
Date: 2017-11-06 09:52
Buffet use peel'n'stick key 'corks' (they're high density foam shapes) across their entire range - while that may be acceptable on a B12/Prodige, it's an absolute farce when fitted to their top line of clarinets as you'd expect an instrument of that level and price to have far more hand finishing done to reflect that.
I don't compress cork strips when I replace tenon corks - I cut them to the required width, bevel one end, glue the strip in place in the tenon slot, trim the excess off and file it down, then sand them down to a barrel shape and they're good to go. I mount the joints in a lathe and spin them at high speed to sand them down to get an even finish.
It seems to be a thing in the US that flat sided tenon corks are the more popular type (as opposed to barrel-shaped tenon corks) and I've also seen them with square leading edges instead of having been rounded or bevelled to reduce them being torn during assembly. I made the comment 'It would be nice to see the tenon corks when they're finished' on a repair page showing photos of clarinet tenon corks that were left flat sided and square edged, only to find out that was them finished. That just look shoddy and amateur in my books. Look up any 'recently overhauled clarinet' listed on eBay's US site and chances are you'll see flat sided tenon corks.
Depending on the tenon and socket arrangement, the finished thickness of the tenon cork will vary - instruments with wooden sockets won't require the tenon corks to be all that wide (maybe around 0.5-1mm wider in diameter to the tenon itself), but instruments with metal sleeved sockets tend to need much thicker tenon corks as they don't grip as well against the smooth walls of the metal sockets.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
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Author: clarnibass
Date: 2017-11-06 15:34
Can you clarify? It sounds like you are saying the cork peels or pushes off when you first try to assemble? That is the glue failing, unless the cork is too thick by an extreme amount.
Of course you'd want to check the fit before putting any grease. With experience you get to know the feel it should have without grease, so you know when to stop sanding before putting any. With good glue there is no problem of it pushing off when doing this.
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Author: Clarineteer
Date: 2017-11-06 16:05
Preparing the tenon before gluing is essential. You must remove all grease and surface oils. I use acetone with a cotton swab (Q-Tip ) on wood tenons only then I wrap the tenon cork after I install it immediately with a velcro strip that i got from Home Depot that is used to contain audio cables. Works perfectly. I also use Ferrees Quick Dry contact cement.
Post Edited (2017-11-07 15:28)
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Author: Matt74
Date: 2017-11-06 22:14
Chris,
My tenon corks always end up looking flat. I bevel the edges before installing, but after sanding you can barely tell. They do look different, but not a lot. I don’t have a lathe, so I sand by hand. I use a thin strip to sand with, less than half the width of the cork. I try to press the edges and everything. They just end up that way. I even “round” them somewhat before installing. They usually aren’t much thicker than the tenon when done.
Maybe if you round them a good bit, it gives them room to squish more, so you can make them thicker. Then, if you make them wider they can’t squish as much and you have to make them thinner. Speculation.
At any rate, square is more American. It’s utilitarian, like a pickup truck. Round is more unique and interesting, like an MG.
- Matthew Simington
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Author: Tony F
Date: 2017-11-07 03:33
Matt74 wrote
"At any rate, square is more American. It’s utilitarian, like a pickup truck. Round is more unique and interesting, like an MG."
Square tears the cork. Chamfered doesn't.
Tony F.
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Author: Matt74
Date: 2017-11-07 06:57
That was only a joke.
- Matthew Simington
Post Edited (2017-11-07 10:47)
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Author: Chris P
Date: 2017-11-07 12:47
When degreasing the tenon slots on both wood and plastic instruments, you're best using alcohol to do this as it won't do any harm. Go over it at least three times to be sure it's well degreased and using a fresh tip of a cotton bud (Q-tip) each time.
I use isopropyl alcohol to degrease tenon slots and keys prior to applying adhesive - isopropyl being the same stuff used for alcohol swaps prior to having injections and it has no colour added to it.
You shouldn't use solvents or acetone on plastics as it can dissolve them. It is safe for use on wood, but not on plastics. Acetone will also dissolve shellac, so an old wooden clarinet with the tenon slots covered in a thick layer of shellac can be thoroughly cleaned with acetone. It also dissolves superglue (cyanoacrylate).
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
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Author: Kalashnikirby
Date: 2017-11-07 22:56
clarnibass wrote:
"Can you clarify? It sounds like you are saying the cork peels or pushes off when you first try to assemble? That is the glue failing, unless the cork is too thick by an extreme amount."
If I don't bevel the edges, yes, that happens. But since the cork doesn't rotate at all when putting the joints together, I don't see any reason not to use my tape. Try for yourself. But contact glue might have superior adhesion, I just prefer residiue-free tape.
The cork quality that we get here is still good, I suppose. Unlike what manufactures install, it doesn't have to be greased every day and still goes very smoothly - I imagine it's more fine pored, while also softer. I'd therefore like to sand down as little as possible. So far it's lasting quite well on my main instrument.
It seems that acetone will leave stains on the instruments, or at least decolourise stained wood, while isopropyl alcohol is safer to use (I clean whole bodies with that if they're too filthy).
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Author: Neil
Date: 2017-11-08 03:33
I've used a hose clamp to compress tenon cork. Put a shim under it so you don't get raised bumps under the slots.
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Author: clarnibass
Date: 2017-11-08 10:12
>> If I don't bevel the edges, yes, that happens. <<
Why would you not bevel the edges? Or at least the outer edge (since the socket isn't trying to "climb" the inner edge anyway)? It takes a few seconds (maybe 30 seconds if it's very slow) so insignificant time.
In your first post you said: "it's almost impossible to fit a barrel without the cork sliding away, as it's never been compressend before."
This is what I mean if you can clarify. If it doesn't happen when you bevel the edge, then bevel edge, which I would recommend to do anyway, problem solved
If it happens often even when beveling, that's the glue not being strong enough IMO or the cork is much too thick. With good glue, even when the cork is much too thick, so much that it's very difficult or even impossible to assemble, the cork still won't slide off.
>> The cork quality that we get here is still good <<
I'm not sure where "here" is (maybe I missed it in one of the posts) but you mentioned Pisoni. I got cork from Pisoni and most other suppliers, including the main one in Portugal which AFAIK most suppliers get their cork from. It's very variable from any source IME.
>> But since the cork doesn't rotate at all when putting the joints together, I don't see any reason not to use my tape. <<
I'm not saying not to use the tape. If it works for you it's fine. I've tried strong double sided tape and decided against it.
It's not surprising it peels/pushes off without rotating. All glues are much better in shear than peel, so it's expected it would do exactly that. Rotating is trying to move the entire glued joint at once (more or less), compared with peeling which is just a small area at a time.
In the extremely rare case that it peels/pushes off even with contact glue, it's exactly the same, doesn't rotate. It's a matter of the amount of force needed to cause it to happen.
Post Edited (2017-11-08 10:14)
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Author: Kalashnikirby
Date: 2017-11-08 20:05
Well my first tenon repair wasn't great as I didn't sand the edges, had weaker tape and thus pushed it all the way down.
Think I did bevel the edges last time, but I'm not sure anymore. I was under the impression that after a few days of use, the cork "sets" and now being fully compressed becomes much thinner than initially thought. Or maybe I prefer a really strong connection. Next time I'll make sure to bevel the edges and see whether I can get a nice, seamless finish and a sufficient thickness.
Some techs, as already mentioned in this thread, seem to sand the cork down to the level of the sockets.
Take a look at this: https://www.oboe-blog.de/galerie/zapfenkorken/
It looks like the same cork that I use (and by "here", I mean here in Germany, where I couldn't get anything different, having bought several plates already) - of course, sanding it down this much will prevent it from sliding away, but doesn't make for a tight fit, IMHO. All I'd like to achieve to keep it as thick as possible
Anyways, thanks for your advice, I really appreciate you experienced techs sharing your knowledge!
Post Edited (2017-11-08 20:06)
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Author: Caroline Smale
Date: 2017-11-09 03:00
The real objective when fitting a tenon cork is just to get a GOOD fit.
GOOD meaning one that assembles relatively easily yet provides a firm and stable connection.
There is no precise measurement or "diagram" that will achieve this result - it comes from understanding that many things interact to achieve the result including --
- Cork quality
- Preferred shape of cork (parallel vs barrel shape)
- distance between the base of the tenon recess and the inside of the socket
- Shape of the tenon recess base
- Diameter of recess (e.g. clarinet bell vs oboe middle joint)
- Surface finish of inside of the socket (smooth/rough) and material (wood/plastic/metal)
- Profile of the socket (parallel or slight taper)
- Customer's preferred degree of fit (easier vs firmer)
A good and experienced tech visualises all of these parameters virtually instantaneously and makes the decision of just what cork thickness to start with and then the fine adustment needed to achieve the end result.
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Author: Matt74
Date: 2017-11-09 05:59
I haven’t noticed that the cork compresses, except after years of use. I’m sure it does a little. Some cork may certainly compress more than others.
I don’t notice it. I usually leave the joints together overnight to compress, but I havent been able to tell any difference. When I corked my horn I made the joints snug thinking they would compress, but they never did. I ended up sanding them down after a year or two. - But I wasn’t playing 5+ hours a day.
I press hard when I first glue them to make sure they are stuck flat everywhere. I roll the freshly glued tenon along the side of the table to get the corks pressed down good and flat. I also use a polished metal tool to make sure the extreme edges are all the way down into the groove. This may compress the cork somewhat.
I wonder if the tape is compressing, or if there are tiny bubbles between the tape and tenon, or between the tape and the cork. - Like when you put tape or a clingy plastic film on glass.
- Matthew Simington
Post Edited (2017-11-09 06:02)
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