 The Clarinet BBoard
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Author: BartHx
Date: 2015-07-12 05:37
I am working on a 1960s-ish Buffet A clarinet. When the owner purchased a set of R13s, this one became an extra and it eventually got loaned out to a friend who needed one. It was on loan for several years and was just recently returned. It appears that the bore got an occasional splash of oil. However, that seems to be the only form of maintenance the person using it believed in. I suspect that part of the reason it was returned was that some of the pads started falling apart and it became unplayable. Anyway, when the tenon corks needed to be replaced, they were just tightly wrapped in multiple layers of dental floss. The problem now is that the tenon corks have been so compressed for so long that they are paper thin and will not peel off as you would normally do. To add to the problem, my lathe and I are currently in two different locations. If necessary, I can take the cork off a tiny piece at a time with a dental pick, but that is likely to take forever. Does anyone have any alternate suggestions for removing the old cork?
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Author: Tony F
Date: 2015-07-12 08:22
I use a craft knife with a chisel-tip blade, followed by some careful work with a curved riffler file. If the tenon has that Buffet corrugated surface than you'll need a rat-tail file if you want to preserve the corrugations, otherwise you could re-profile it to flat. It only takes a few minutes to strip and clean up a tenon.
Tony F.
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Author: Chris P
Date: 2015-07-12 09:30
Use the tip of a screwdriver to scrape the cork and old adhesive from the grooves. Also be patient - you don't need to use a lathe to do this.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
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Author: clarnibass
Date: 2015-07-12 10:18
Use something to scrape it off, a knife, a scraper, pliers, anything is ok as long as you are careful not to damage the body itself. I most often use pliers and if you are worried or affraid you won't have the feel for it, you can use a stop so the pliers can't close to smaller than the tenon diameter itself.
You can clean any left over glue with light fluid (or sometimes alcohol). Sometimes lighter fluid can help removing glue so some chunks of cork that hard to remove will be easier after that.
I also sometimes use a hard plastic and/or brass brush in a micromotor to really clean everything, especially some hard to reach places like the corners, inside grooves, etc.
I have a lathe right next to me and pretty much never use it for that.
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Author: BartHx
Date: 2015-07-12 19:18
Thank you for the suggestions. Unfortunately this cork is well beyond all but the last one. It's paper thin, extremely dry, and brittle. I have done many tenons and, Tony and Chris, your suggestions are very good and the normal way I approach them. Unfortunately, these corks have been squashed so thin and are so dry there is nothing left to get under and lift. My thinking with the lathe was something like clarnibass's suggestion of the brush in a micromotor, just moving the joint instead of the brush. The closest thing I can relate it to would be like trying to remove a heavy layer of paint. This Buffet is old enough that the tenons are grooved rather than wavy. I searched the archive and found the suggestion that tenons be cut smooth for better adhesion (again the thought of the lathe). I have no idea what the adhesive is, so have no idea where to start with a solvent.
I did try a brush on a micromotor and was able to get the cork off of one tenon as a very dry dust. Where the adhesive was heavy enough that I could not feel the grooves with my thumbnail, I used a dental pick to get down to the wood. That looks like it is going to be my best bet for the other tenons as well.
Again, thank you for your input. Just don't ask me my opinion of people who borrow other people's instruments for long periods of time and do nothing about maintenance.
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Author: Chris P
Date: 2015-07-12 22:09
You don't need to lift anything - use a bench peg and rotate the joints while scraping (or more like ploughing) through the old tenon corks with the screwdriver tip turned so it fits thinways into the grooves to clean them out, then the remainder of the old cork that's glued to the peaks can be scraped off using the screwdriver blade set flat against them.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
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Author: clarnibass
Date: 2015-07-12 23:54
Even if the cork is really dry and thin, it's very unlikely that you wouldn't be able to scrape it off. I do that before the micromotore because it's faster. The pliers is best to remove most and if you have a feel for it it's not dangerous.
The brass brush on the dental micromotor usually removes every last trace of cork and some lighter fluid and/or alcohol removes any left over glue. It's a lot faster to remove left overs than scraping them.
Keep in mind that if you machine the grooves flat you might need to use a cork that is thicker than you'd want to use. Or you could use one of several methods to compensate for it and use a cork of a thickness you want.
Post Edited (2015-07-13 08:48)
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Author: BartHx
Date: 2015-07-13 01:53
I think what I am doing is something of a combination of the above suggestions. The cork comes off quickly, easily, and cleanly with a brush. Rather than a screwdriver to clean the grooves, I am using dental tools (I have a generous dentist and find those tools easier to control for this purpose). We all seem to be thinking along the same general lines. I'll experiment with solvents on the last of the adhesive before I start putting new cork on. Again, thank you all for your input.
Whatever the adhesive is, it is quite hard and the brush does not do particularly well at removing it. Scraping seems to be the logical option there. The brush needs to have most of it gone before it is effective at that level.
Post Edited (2015-07-13 02:01)
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Author: BartHx
Date: 2015-07-13 02:43
The adhesive must be shellac. Alcohol does a great job of final clean-up.
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Author: Chris P
Date: 2015-07-13 03:18
When it comes to replacing the tenon corks, please don't use shellac even though it was used before. After thoroughly cleaning up and degreasing the tenon slots (with alcohol and cotton rags torn into strips to strop the slots with), use a good quality contact adhesive where you coat both the surfaces to be bonded, leave them to sit for a few minutes until the adhesive is touch dry (but slightly tacky) then press both glued surfaces together to form a bond.
The problem with shellac is you need to get it very hot to make it liquid, then try to keep it liquid while sticking on the tenon cork. You'll probably see from this clarinet that it isn't evenly distributed and there may be areas that may not have bonded due to being too cold by the time the cork strip was applied (they also most likely used a hot steel blade to melt the shellac to the cork during application to avoid that). And when it comes to removing it, wear goggles or glasses as bits of shellac can get into your eyes when they're chipped off which isn't pleasant.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
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Author: Chris P
Date: 2015-07-13 03:59
Deeply grooved tenon slots were really designed for use with shellac to be sure it bonded well to the wood and the cork slot sat on top of the lines of shellac filling the grooves.
But with the much better adhesives we use now, it's best to have completely flat tenon slots as that provides maximum contact between the tenon slot and the cork strip as they're both completely flat - with a grooved tenon slot, the cork strip will only make contact with the peaks and leave voids where the troughs are as the cork strip won't conform to the grooves, so far less contact area and more likely to fail.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
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Author: BartHx
Date: 2015-07-13 06:05
Fortunately, the grooves on these tenons are fairly fine and quite shallow. We are definitely in agreement on the use of contact cement. Now that I can finally see what is there, this size groove has never given me any problems with contact cement. Again, thank you to all for your input. I am amazed at how thin and hard this cork managed to get.
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Author: Tony F
Date: 2015-07-14 10:50
Contact adhesive does a better job of securing tenon corks than shellac, but it can be degraded over time by contact with mineral oils. As long as you avoid mineral-based cork grease, which is a good idea anyway, there shouldn't be a problem. Shellac can crystallize over time, thus losing any adhesive properties it may have had.
Tony F.
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Author: Tony F
Date: 2015-07-14 12:30
I've stripped old tenon corks which had become loose on the tenon. The shellac under them had crystallized into something resembling powdered sugar. Unless someone is using nitrocellulose lacquer to fit tenon corks this was crystallized shellac. Over time I have seen several of these. I've also seen this under very old pads.
Tony F.
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Author: BartHx
Date: 2015-07-14 20:13
As a photographer, I am familiar with and try to stay away from nitrocellulose. When it gets old, it also becomes extremely flammable. It was a nitrocellulose negative that caused the original Ansel Adams studio in Yosemite to burn down many, many years ago. That's why his famous photo of Half Dome is cropped at the top. The negative was damaged in the fire (That came directly from Ansel -- he was not happy with having to crop it). Sometimes a nitrocellulose negative can just collapse into dust when you pick it up. They are properly stored in air tight cans. Although someone surely has used it, I don't see it as an effective adhesive over the long run.
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