 The Clarinet BBoard
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Author: Rusty
Date: 2010-03-26 20:26
I know, there has been lots of good posts explaining how to do this but right now when I need one they are being elusive. Just posting in "Search" lists lots of repairers who want to do it for you.
Would someone please give me a previous contact that details this? Thanks.
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Author: Rusty
Date: 2010-03-26 20:56
Talk about "service with a smile" I only posted 10 mins ago, had a bowl of cereal, came back and there`s a reply from GBK. Thanks.
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Author: Rusty
Date: 2010-03-26 23:41
Aw! no that is going too far David we are only talking about a bit of cork and to post, it would have to travel right across the Pacific and the dog wants his bowl back anyway.
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Author: clarnibass
Date: 2010-03-28 08:23
Some suggestions (a bit different than the Music Medic article):
1/16" is too thick a lot of the times. Even if it's not too thick for the tenon, it's so thick that it will compress more than I like long term. Thicker cork that feels as tight at first is the same as a softer material. If this thickness is necessary I consider there is a too big gap in the tenon and use a method so the cork is usual thickness but works correct. 1.2mm is the most common thickness for tenons (the thickest I will use by itself is probably 1.4mm, sanded a bit). You can start with 1/16" and might have to sand a lot, which is fine. Thicker cork will tend to break/crack more easily too.
Test the glue dryness with your finger. Drying time depends a lot on the type of glue, weather and how thick you spread it. If I waited 5-10 minutes as suggested it would be far too long. You can usually ignore the suggestion on the glue package (mine says 10-40 minutes - I wait no more than 3 minutes, usually less).
I sand a bevel width-wise before gluing. Always on the side that is going to be the outer end, usually (a smaller one) also on the side that is the inner end. I don't want to sand these edges after the cork is glued because of the risk of sanding the wood/plastic. No matter how careful you are, there's a risk. Especially if you use the shoe-shine method, which I don't like, and instead prefer a rigid sanding tool which has much more control. It's also much easier to sand before the cork is glued to the tenon, so any sanding done before is better.
I prefer not to start gluing at the bevel on the very end. I start a bit after because it's easier to align a middle part. Then I continue with the bevel first, then the rest.
BTW sometimes removing the old cork will take most of the time of the replacement.
Post Edited (2010-03-28 08:24)
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Author: Caroline Smale
Date: 2010-03-28 19:32
The thickness of cork required on a tenon joint is largely dependant on 3 things.
1). the difference in diameter between socket and base of tenon groove.
2). shape of base of groove (virtually flat is best).
3). the quality and resilience of the cork.
The last point is crucial as quality varies so widely and really good cork is increasingly difficult to get. Only experience really helps to decide on this and how to compensate with the dimensions.
Generally speaking with good cork on an average tenon I use 1.6mm and then sand to get a good fit.
With less resilient cork there is little leeway and you need to have outer diameter or cork only slightly larger than the socket.
For the centre tenon a reasonably firm fit is needed to provide the final degree of rigidity and friction to the joint.
Finally unfilled cork (the pores not filled with gunk to make it look good) is by far the best for tenons but many suppliers don't stock it. I had to go direct to a producer in Portugal and persuade them to send me cork with this manufacturing stage ommited to get my last lot.
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Author: tictactux ★2017
Date: 2010-03-28 19:59
I use 1/16" cork and sand it down to kinda barrel shape. Near the edge it isn't thicker than the tenon itself which reduces the danger of damage when the joints are carelessly shoved together. I once tried thinner cork but it was only a wobbly fit. Not all tenons are cut the same, so I prefer sanding over doing the work twice.
Cork harvested by redhead virgins at new moon is best. Closely followed by whatever MusicMedic is mailing me. :-)
--
Ben
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Author: Chris P
Date: 2010-03-28 20:25
I do most of my final sanding/shaping by mounting the joint between lathe centres, spin at high speed and sand the cork with the end of a folded up piece of abrasive paper/cloth.
On instruments with joints that are too long to fit between a 300mm lathe's centres (eg. cor anglais or alto clarinet joints) I'd start by trimming the tenon cork with a scalpel (using the bench peg to steady it and turning by hand the joint so the cork gets trimmed off around the entire circumference) to get the initial barrel shape, then finish off by sanding in the 'shoe-shine' manner.
I make most tenon corks barrel shaped ( ) rather than leaving too much of a flat on it - though that depends on the length of the tenon and width of the cork strip. With instruments fitted with an articulated C#/G# where the tonehole goes through the tenon (and the tenon is usually longer on these) then I'd make the tenon cork with a much wider flat area instead of completely barrel shaped.
On instruments with lined sockets, leave the tenon cork much thicker as the amount of grip between the greased cork and metal liner is far less on these than unlined tenons. The cork will compress (provided it's greased well) and will exert enough outward pressure to keep the joint together.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
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Author: Rusty
Date: 2010-03-28 20:28
All this talk about cork has got me worried now because I have just bought some HyTek Real cork in pre cut strips. Somewhere I read it was a combination with some Teflon in it.
Anyone used it, hope it works? 1.59mm in thickness
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Author: jbutler ★2017
Date: 2010-03-30 03:27
1.59 may require a bit of sanding but you'll be okay. I've never used HyTek cork for tenons as I prefer a select grade natural sheet cork. I'm more concerned about the "pre-cut" strips. Hopefully the supplier has a knowledge of how wide they should be for your application. I always measure each tenon with a digital caliper. Just consider it a "learning" experience if it doesn't go perfectly.
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Author: Gordon (NZ)
Date: 2010-04-01 10:07
I bought pre-cut once, and it was too narrow for about half the tenons I do.
Furthermore, it is more tricky to trim a narrow pre-cut to the right width than it is to cut a correct width strip from a large sheet.
My approach is similar to Clarnibass's
To select a suitable thickness I roughly find the difference in the diameter of the tenon groove and the socket, with my calliper, multiply it by approx 1.5, then divide by 2.
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Author: clarnibass
Date: 2010-04-01 11:42
>> 1.59 may require a bit of sanding but you'll be okay. <<
How can you know? I found sometimes even 1.2mm is boarderline too thin and sometimes 1.6mm (which I generally think is too thick) is not thick enough. It's really specific.
>> I use 1/16" cork and sand it down to kinda barrel shape. <<
>> I make most tenon corks barrel shaped <<
The problem with barrel sometimes is for short (width-wise) tenons which many middle tenons are. For these sometimes leaving as much supporting thickness of cork is best and a barrel shape will remove some of that.
>> with good cork on an average tenon I use 1.6mm and then sand to get a good fit. <<
There are two reasons I prefer to start with a cork closer to the end thickness instead of 1.6mm and sand more. First it is faster if I don't need to sand a lot. Second the thicker the cork the more it is likely to crack, regardless of quality.
>> Finally unfilled cork (the pores not filled with gunk to make it look good) is by far the best for tenons but many suppliers don't stock it. <<
There are different fillers and some are significantly better than others. I remember at least three.
- One is a really hard dark material that is very difficult to sand or even cut and looks terrible. It tends sometimes not to sand while sanding the cork around it. This is the worst.
- Another type looks much better, a bit darker than the cork but matches the colour much better. It is not as hard but still harder to sand than the cork.
- The best type looks the best, still a little darker than the cork most of the time. It is not nearly as hard and sands pretty much the same as the cork.
Natural cork with only tiny holes, really the best quality, is extremely hard to get. The cork that is advertised as best or extra good quality is not like this. I once tried a sheet of this especially good quality cork just to see. One sheet of 1.6mm cork cost me about $40. Comparing with the best method filled cork, I found no real advantage.
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Author: jbutler ★2017
Date: 2010-04-02 21:18
"How can you know? I found sometimes even 1.2mm is boarderline too thin and sometimes 1.6mm (which I generally think is too thick) is not thick enough. It's really specific."
Perhaps you didn't see the word "may" included in the sentence. I also said to consider it a learning experience if it didn't go well.
Geesh, I believe I've replaced thousands of tenon corks since I began repairing in 1976. Give it a break clarnibass.......it's not like it can't be redone if incorrect.
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Author: jasperbay
Date: 2010-04-04 00:02
I read somewhere (probably in a much earlier thread on cork replacement) that you can make the cork softer and more flexible for wrapping around the tenon by laying the strip on a steel block, and tapping it gently all over with a hammer with a slightly rounded face. This works especially well on the harder cork that probably wouldn't have even been sold in the 'good old days', although it does tend to knock out the non-cork filler if you're not careful. This can be looked at as either good, or bad, depending on wether you wanted that big chunk of filler on your tenon or not.
I find this procedure unnessesary on good, soft cork, but almost mandatory on harder cork that wants to crack while wrapping around the tenon.
Clark G. Sherwood
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Author: skygardener
Date: 2010-04-04 03:36
Since we are on it...
In all cases, if you put a new cork on the tenon, it will compress and be thinner in a few days than it was when you put it on. This often leads to instability in the tenons and may require you to replace the tenon and start over. If you put on a thicker cork, then you end up with a good fit, but the first few days are a bit dangerous. The thickness might cause the cork to just tear off.
Better than tapping with a hammer is to PRE-compress the cork with a vise.
Put the entire thing in the vise and tighten it down and leave it there for a few minutes. Then put the glue on and proceed as normal. This saves a lot of hassle because the cork won't compress much after this point and when you do the final sanding and fitting, you know exactly what you are dealing with.
I pre-compress all the corks on any part of the clarinet. This is also good for the corks under the keys. It happens that you can put the key cork on, and the pad height is good and even, but then a few weeks later the cork has become dented (like the RH Ab/Eb) and the height is more than you want. Pre-compressing avoids all this at the cost of a few extra minutes.
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Author: Rusty
Date: 2010-04-04 08:42
Heh! that`s cunning. What a good suggestion. Thanks.
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Author: Chris P
Date: 2010-04-04 16:13
For key corks I prefer to keep the use of natural cork to a minimum - using tech cork/rubco/gummi-kork/etc. for stopper corks on closed keys and linkages, and ultrasuede on the key feet of open standing keys. I only use natural cork on the throat A key as that can be shaped much easier than a thick piece of tech cork.
I know some others on here will be against the use of ultrasuede due to it being spongy, but if you understand and incorporate that property of it in what you do, then it won't cause any problems. I've never had any problems with it and can safely say it works fine for me.
The fact is all woodwind mechanisms aren't an exact science, and add to that the various types of silencing material and it's even less of an exact science. So hardly worth wasting too much time evaluating and disussing the pros and cons of this, that and the other material and just getting on with the job and making it work as best as you can. If that doesn't work, do something else.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
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Author: Gordon (NZ)
Date: 2010-04-04 23:24
Jasperbay wrote "...you can make the cork softer and more flexible for wrapping around the tenon by laying the strip on a steel block, and tapping it gently all over with a hammer with a slightly rounded face."
FWIW I find it easier and quicker to simply roll the strip, with anything cylindrical, say 3/4" - 1" diameter, and long enough to get a good hold of.
I tried the vice method too, but personally prefer the rolling, because it already helps the cork to curve around. (So roll on the underside.)
And really only bother doing it when there is a risk of the cork cracking, eg around a smallish diameter tube, with dryish cork. (Good for bassoon bocals)
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Author: clarnibass
Date: 2010-04-05 05:44
>> Perhaps you didn't see the word "may" included in the sentence. <<
I saw it and it only referred to it may require sanding, but anyway... re "give it a break" I think it's worth posting any information that will help others understand more details and possibilities about this or any other repairs. Otherwise they might find out themsevles... one day... or not. I really don't see a problem with giving as much detail as possible.
>> I know some others on here will be against the use of ultrasuede <<
Those of us who don't really like ultrasuade really only mean for linkages. You said you don't use it for linkages, only as bumpers, so no problem.
>> I only use natural cork on the throat A key as that can be shaped much easier than a thick piece of tech cork. <<
I use natrual cork sometimes on a few places on saxophones, but I don't remember the last time I used on clarinets (except for tenon corks). For the A key, sometimes just a thin layer is needed. When a very thick "cork" is needed for that key, here is what I usually do.
Measure what cork thickness is needed (by eyeing it, or comparing with the old cork if it's there, or several other ways). Then glue rubber-cork (aka tech-cork, aka lots of other names) to the key. Then shape it with a micromotor, very fast. Sometimes I will shape it to approx 0.5mm too thin, then glue 0.5mm synthetic felt to it, to make it quieter. Sometimes this requires an extra step of mounting the key to check the thickness with the synth felt is correct before gluing.
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Author: Gordon (NZ)
Date: 2010-04-05 06:47
When cork needs to be thick for the throat A, I prefer agglomerated cork.
Occasionally I use a micro-motor unit to trim it, as does Clarnibass, but usually just a very sharp knife. It helps to cut it to only slightly larger than necessary before gluing it on.
I usually put it on slightly too thick, and then use sandpaper glued to a narrow strip of thin, stiff material - fingernail board style - to adjust thickness while on the clarinet.
Actually, the sanding is to create a small flat on the cork, where it contacts the clarinet body. This reduces the squishiness introduced by only an edge hitting the clarinet body.
This cork, when thick, does not have the squishy feel that thick natural cork has. That is why I use it here.
I don't apologise for giving the detail. For all woodwind repair work, the devil is in the detail. The detail is what gives a top quality result.
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Author: Chris P
Date: 2010-04-05 17:38
On the throat A key I use a cork pad that has surface imperfections in it, which is sliced obliquely to form a wedge shape (and both halves can be used) which is in turn glued onto the underside of the throat A touch. This also offers a large contact area on the joint surface rather than an edge.
On tenon corks, once they're glued into place and the overlapping bit has been filed off, I then press and roll the tenon cork against the edge of the bench surface to be sure it is bedded onto the glue. Buffet's wavy tenon recesses are a pain when it comes to this, and fitting tenon corks in general. Far better to have a flat or a slightly domed (but smooth) base to the tenon recess than a deeply ridged, grooved or wavy one.
Hardly anyone uses shellac to glue tenon corks on nowadays, so no need for deep ridges, grooves and waves as impact adhesive is best used on a completely flat surface. Cork is flat so that offers the best surface to glue against a flat surface, and you're hardly ever likely to get cork with grooves or waves cut into one side of it to match the surface of the tenon recess. The best contacting surfaces are two identical ones - ie. both being flat.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
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Author: Gordon (NZ)
Date: 2010-04-05 23:23
"Far better to have a flat or a slightly domed (but smooth) base to the tenon recess than a deeply ridged, grooved or wavy one. "
Indeed! What on earth are these manufacturers thinking of?
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Author: skygardener
Date: 2010-04-05 23:44
Chris P-On the throat A key I use a cork pad that has surface imperfections in it, which is sliced obliquely to form a wedge shape (and both halves can be used) which is in turn glued onto the underside of the throat A touch. This also offers a large contact area on the joint surface rather than an edge.
--
In which direction do you put the wedge shape on?
--
PS. To my above post about the vise-
I use the vise on all cushions for tenons and keys, even if the material is not really cork. I pre-compress just about all of them- leathers and synthetics of any kind. They all can compress, so this avoids all that hassle later on.
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Author: Chris P
Date: 2010-04-06 01:37
Attachment: throatAstopper.jpg (16k)
Attached is a diagram how I'd shape the cork stopper on the throat A key.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
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Author: skygardener
Date: 2010-04-06 04:17
That explains my confusion- I thought you meant the contact for the screw touch point. Don't know why I was thinking that... ![[huh]](http://test.woodwind.org/clarinet/BBoard/smileys/smilie11.gif)
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Author: clarnibass
Date: 2010-04-06 04:28
Yes, to create that flat is what I meant by "shape". So I either shape it like that, or, still with a flat, make it a little too thin and glue 0.5mm synth flet over it, so the felt hits the body normally rather than on its edge.
I also sometimes use a knife like Gordon but I prefer to use the micromotor only because I managed to cut myself with the knife a few times but never hurt myself with the micromotor. The difference in time it takes is very small (a few seconds maybe) or sometimes no difference.
I also use a nail file to make it thinner while on the instrument, but only sometimes. Since I prefer rubber-cork, it is harder to sand so I try to aim getting it exactly right before and then sand only very little if necessary. The micromotor sands it very fast so no problem with the material in this case.
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