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Cork Replacement: Clarinet Instrument Repair

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Cork Replacement: Clarinet Instrument Repair
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Hi, this is Master Sergeant, Dale Barton today we’re going to be talking about cork, specifically tenant corks on clarinets oboes and such that also applies to mouthpiece corks, some of the first kind of don’ts on these when they’re loose attempting to reglue them often is a really Bad idea it makes for a big mess, for you makes for a big mess for the repairmen later on to have to clean up. I know that it works it’s kind of an expedient method. If you have a loose cork, you have one that the corks come off. Your best friend is teflon plumbers tape. If you’ve got that this joints coming apart, it’s just hanging in the wind to start it in one end work your way down wherever you need to. If you’ve got a really loose spot, you can build up a number of layers. It sticks to itself, it works really great. It’S inherently slippery things come on and off you don’t even hardly need any cork grease later on and and usually it sticks a lot better than that to itself, and then it can come off by itself. Masking tape is bad. It leaves a lot of residue that makes it difficult to get it off, but right now I just would kind of like to teach you how to properly replace one of these clerks now, one of the first things if you’ve got an old, worn one. For example, this one here is in great shape and it’s a little bit dark, but there’s nothing wrong with it, but it just the barrel doesn’t stick to this instrument, so that makes it really difficult for the player to keep the instrument in tune. They can lose parts, have parts fall off, so this tool is a cork scraper, tenon, cork remover. There are things that you could use to try to get the cork off, but the biggest thing that you want to do is avoid removing wood from the instruments. So once I’ve got under here and I can start to peel the cork off a little bit, you can kind of see that I can peel that off. If I’m scraping enough that I’m removing wood that’s kind of a bad thing. So if you really can’t get this cork off I’ll show you something else that we’ll want to do one other thing is once we’ve gotten the edge of the of the cork visible you can take acetone. I usually have a little more industrial grade. Acetone fingernail polish remover is essentially acetone with with some moisturizers and a little bit of fragrance, but get a little bit of that in there get it along the edge of the cork and it will it’ll kind of seep underneath there and start to dissolve that glue. So that you can, then you get a little bit further along put a little bit more on. It comes out this way. If we have especially on an older instrument where the corks been there a long time, sometimes you just can’t get the old glue off. One trick that I have found the best thing for removing old contact cement is new contacts of it. So you take a little bit of your contact. Cement put it over the old crusty glue, spread it around just a little bit, believe it thick and let it kind of sit there for a bit and the solvents that are in the kind of thick glue will start to dissolve the old glue. And then, at this point you kind of do like you used to do with rubber cement when you were a kid and you’d make it into little balls and things. So we we just rub our finger across that until it starts to get the glue and it’ll start to ball up, and you can probably already see that we’re we’re getting that balled up glue off of there, and that leaves us with a really nice clean surface. Before we put the cork on, we also want to make sure that the whole surface is clean. Can the fingernail polish remover works? Okay, acetone and just the pure acetone is what I like on a q-tip get it in there. It evaporates almost instantly. It works good. On wood and on plastic, if you have a plastic instrument, you want to be real, careful about using alcohol, for whatever reason the structure of the ABS plastic that most student instruments are made of. It becomes very crystalline when it comes in contact with the alcohol, which is a number one thing for breaking the middle joints on clarinets is because in the past somebody has replaced the cork cleaned it with alcohol. Unwittingly, messed up the molecules of this thing and you end up either having to replace the instrument to have a very expensive repair. Okay, so that’s nice and clean one other thing: I use contact cement, but for many years instrument corks were put on with shellac. It kind of like looks like this. This is a plastic adhesive, but shellac comes in a stick form. It’S very hard, brittle actually excreted from a beetle that that’s in India, they scrape the stuff off the trees form it into these things. You’Ve eaten it it’s what makes the shine on your apples and oranges. It’S a really great substance. It’S sticky enough that when melted it’ll hold quarks and things on, but it’s it doesn’t come off quite as quite the same way. It is dissolvable, however, in alcohol. So if you have an instrument where the cork is put on with shellac, then the alcohol will be your choice for cleaning off the excess material. Now, I’m going to have the assumption that you do at least have access to some sheet cork material, the better variety of thicknesses. You have the easier your job is. Sometimes you just don’t have too much so the first thing that we’re going to do is trim the cork to fit in this channel as far as finding out the thickness of the cork. If it was working pretty well and you’ve got some of the remnant of the old cork and it’s just a little bit a little bit loose, you can kind of compare it to some of your sheet stock and find something that will be a pretty close fit. It needs to be thicker than what you did before if you can find one, that’s exactly that’s ideal, but that happens in the fairy tales first thing that I want to do is make sure that I’ve got a really nice straight edge in my shop. I go through tons of single edge, razor blades and q-tips and pipe cleaners. It’S one of those things I just have them on hand. I don’t try to skimp on them. I get them, I use them. I throw them away, they’re, just handy enough and cheap enough. That you don’t really need to worry about that, so get a good ruler. A metal straightedge is nicer, but for the first few times the plastic one will work until you start to gauge up the edge a little bit so just a little bit on the edge get a good cutting board these. These mats that you get from the fabric stores work really well. You can use a plastic cutting board that you can get in the kitchen department that works. You know you can use a wooden thing, but your you know your wife, your mother, the maid is going to be real mad when they see these big score marks on there. So so we just start by making sure we got a nice clean edge. There’S all kinds of things: I’ve seen people with with calipers and measuring things and all kinds of stuff to try to get the proper width. I’Ve found a method that works just so slick. I put the edge of the cork on one side and I hold it down and now I’ll be following the this shoulder on the other side, with my razor blade, so that is going to be a guide here. So I start the razor blade here and I just Rock just rocking enough to make a tab. Okay, we go to the other side of our sheet material and we do the same thing. So I’ve got a tab on this end. A tab on that end. Now, with those bets up a little bit, those now act as a stop for my straightedge, so I put the straightedge right up to those little tabs. Just gently push it in there not too hard hold it fast. Okay, now that’s already the perfect width for our channel. That was really easy. I can do that in just seconds then the next thing on a on a 10m cork, you want the cork to overlap. You want a bevel on one side and the other one on the other side. You don’t want it to butt up like this, so we don’t just cut it. Flush bring it around and cut it flush, that’s a spot for the air to get out cause a leak on your instrument. We want that overlap that makes sure that it’s sealed all along the way. So yeah again I see people with files, sandpaper and all kinds of stuff. If you do have one side of the cork that, for whatever reason you want it to be the upper face that you see, that part faces down if you’ve got particularly old and brittle cork, and you can kind of tell that it naturally bends one way or The other, because you’re going to have to wrap this around you want it to be flexible enough to do that. If you’re doing that, and it’s feeling kind of crinkly or whatever then position again, this will be the outside that will be down on the bench if you’re using cork, which is somewhat old, it’s a good idea initially to kind of soften up the you know, kind Of a meat tenderizer thing, so you’ll soften up your cork. That makes it more pliable easier to bend. Okay back to the bevel, we’ve got the good side facing down. We take a razor blade if we’re doing a clarinet. You know a narrow cork. We just use the razor blade. I have it facing this way at an angle, and I just draw it towards myself with a slicing motion, and that leaves us a bevel. Okay, next thing that we’re going to do is apply the the cement I use contact cement. It’S either called contact, cement, contact, adhesive every now and then you’ll get one. That’S like a all-purpose adhesive, and if, when you’re reading the instructions it says apply to one side and then apply to the other side and let it dry before connecting it. That’S a contact. Cement, but those types don’t tend to be nearly as good quality is what we’re going to want on here. So first thing that we’re going to do is place a little bit of glue. Just on that bevel surface. This is going to wrap around and it needs to have a glued surface for the other side to to grab. So I put just the tiniest amount of contact cement there. I spread this on that bevel with my pinkie. You want just enough of it for it to be a sheen, you see if you can. Okay, any any glue that goes past. The bevel is something you’re going to have to clean up afterwards and it it just makes things difficult. If you do it this way, it just takes care of itself. Then we go on to the side that is next to the instrument, I’ll put a like a bead of glue and then I go kind of in a sideways motion this to spread it to the outside. Ideally, you don’t want a lot of glue on the edges. You want it on the surface that is contacting the the court channel, but not anywhere else. So again, not a thick coating but a complete coating. It needs to coat the whole thing. It’S real important that you get fresh glue if you’re buying it from somewhere. That hasn’t turned over their stock in 15 years. You’Re going to have issues with this, so a nice coat on that set. That aside, we move to the the joint itself I’ll put a little bit. Thicker glob see that and then I use my my index finger and as I’m pressing it I kind of I twist it and it it spreads the glue side to side right in front of my finger that that thing so I’ll just kind of go this way Until it has spread that, ideally, you want to avoid having too much cement along this surface, if you’re really good, with your your finger tip and how you spread, that you can kind of only get it edge to edge really good, but that doesn’t always happen. It’S not that hard to clean off now we’re going to let this dry a second it if you’ve got the good glue and you haven’t put it on too thickly it’ll dry in under five minutes. Okay, now we take our cork. The glued surface is facing that direction or towards the glued part of the clarinet. The bevel that we’ve cut and glued is facing to the left. If you’re left-handed, you may find that it works easier for you to reverse these things, but that’s the way that goes so. The first thing I’m going to do is carefully place that glued portion between the channels. If, for some reason, you cut this, just a little bit wide try to kind of flex the cork a little bit, lay it in there and allow it to then work side to side. But first we put that in there do a gentle press down with your finger, but not too much as we go around the corner. I want to press downward, but I also want to tug just a little bit on this cork that shrinking stuff tends to just pull everything tight when I’m done so and as I’m going around, I want to keep this really nicely centered between the edges on it. If you had it perfect, it’s just going to slide right in there, but the contacts event is also so aggressive that if you get off to the side, it’ll stick to any glue that is outside of the channel and make it hard for you to get your Cork back in so nice and easy around as we get to the overlap, that’s where you want to really be sure that it’s that it’s touching really good. At that point, I’ll press that down nice and tight get the razor blade. I want to have the razor blade flush with this. I don’t want if I’m like this, and I go to trim this, I’m going to have kind of a scooped out area on that overlap. Ideally, when this is done, we want this to just look perfect and almost undetectable. So first thing I’ll do is I’ll just come in here and with razor blades a lot of times. People will just try to do a straight cut or whatever kind of imagine a scissor with with these blades that go past each other and your cuts, you want to slice through them. You don’t want to just jam it through. You want to gently slice so, even though I’m in here I’m using a little bit of a slicing motion here to get that that excess off right now, we could see that we’re just a little bit high on your first cut. You do kind of want this to be just a little bit high so that you can see what you’re up against. If you had managed to find cork, that was like absolutely perfect in thickness. You really don’t want to sand any of it off because then you’re just removing what you’ve just done. But if it’s just a little bit thick, we want to get it just get that little hump out of the way for right now. Okay, so that’s that’s! And now this is not going to fit, but we don’t want it to fit, but you can test it just to see where you are so next thing. We’Re going to do. Is we’re going to sand this court you’re going to want to get a good quality of wet or dry sandpaper, or something with a very even grit on it, something between like 220 grit up to 400, the higher the number the smoother it cuts, but the longer It takes you to cut, make yourself a strip of sandpaper a little bit narrower than the one that we already cut. Okay, now one thing with this: as we’re sanding, you can do things a couple of ways you can hold it and use a drawing motion as we go around most repairmen have what’s called a bench peg, which is a is a peg that goes in the side Of their bench that you can rest the instrument against and rotate it and it’s held between your body and the bench if you’ve got a really high tech thing, you can set this in a lathe and turn it. So we’ve got our strip of sand paper and we’re sanding on it. But typically, you end up having to cut a whole bunch of strips because it wants to break as you’re going along something that really is going to prevent that and give you just a little more life out of your sandpaper is to take some type of packing Tape or you can use masking tape whatever, on the back of your sandpaper, put a coat of this down. Okay. Now, when we, when we use this, this is significantly stronger and I can’t get that to come apart to save my life. So let’s come back, but I’m going to assume that you don’t have a bench peg. So the things you really want to be aware of is to not sand the wood. You just want to get the cork and avoid sanding the wood. That’S going to give you the more of the longevity for your instrument, the way that I wrapped this tenon cork has the overlap going this way at this point, so it wrapped around it’s this way. We want to sand in this direction so that all the sanding that we do is feathering that overlap in this direction. If we sand this way, it wants to lift that up and pull that joint apart, so make sure that you’re aware of what direction you put. Your cork on okay, so now I’m pressing down pressing down with my thumb and drawing stuff. I want to have this draw a bit of a portion down. I don’t really want it right under my finger, because that creates a lot of scalloped things as I go around. So I start by just gently pulling this sandpaper around being real careful to keep it on a nice parallel line, so that I don’t that I don’t end up standing the actual body. Okay and you’ll keep you’ll, keep doing this looking at it, trying it and tell it until it’s a good fit. This is really getting very close already, I’m quite surprised also after you’ve gotten the glue on you need to take one time of finding a surface and very firmly press and go all the way around. The contact. Cement gets its its strength from a chemical bond that occurs out after the things have dried, then they come back in contact with each other and having that little extra press gives them a lot more longevity once you’ve done a quark this way. Typically, it’s not coming off because it was not put on properly it’s going to come off for some other reason way down the road. So we’ve got the cork on it’s sanded, it’s pretty clean. The biggest reason that I found that corks fall off is the the cork grease that people use. Sometimes it tends to be really thin. It’S got a lot of solvents and those solvents kind of migrate through the cork and they kind of attack the contact cement or whatever glue was on it before so. Sometimes you’ll get one you’ll you’ll take your barrel off or you pull your mouthpiece out and you’ll. Have this round ring of cork? That’S usually because of the cork grease going and migrating through the cork. So, to prevent that we’re going to lay down a barrier of paraffin wax paraffin wax you can find in a block form the stuff it tends to be in the either the baking and preserving section of a grocery store or next to, like the charcoal, lighter fluid. Some of those areas where I find this stuff – another thing you can use is just a plain white candle. The you know the closer to this color. It is the more pure paraffin it is. So what we want to do is we’ll melt this and apply it to the cork to create kind of a base thing. I use a alcohol lamp which has denatured alcohol as the fuel. If you don’t have that, you can also take a cigarette, lighter you’ll need to find something to hold this tab down. Take a rubber band, just anything on there to hold that down, and then another lighter to light. So that keeps that going keeps both of your hands-free. You could then melt your wax put it on here. That tends to get particularly hot, but it does work and works. Well, I kind of like how clean the flame is on a regular alcohol lamp. So we we melt the paraffin and we just work our way around the joint that we’ve just corked and we get us. You want to make sure that that anytime they move it that it’s actually melted wax. You don’t want to just be spreading the wax. You want the hot wax to actually kind of melt into the cork a little bit so once we get that coated all the way around between your thumb and index finger. We’Re going to rub that you want to press really hard that the friction that you create here I mean it gets really hot and that will melt that wax again and drives the wax into the cork. So you can see, we’ve got the excess a bit of the excess wax there. We wipe off the rest of of the wax make sure. As you work that you get everything nice and clean there is, you know I mean people say well. The cork is a cork, it just holds the thing together, but there’s something about a really well done: cork, that’s nice and clean and white and wealth is well fit and that you can’t find the joint that is just really pleasing to technician to the player. They may not even know what it is, but they look at it and go wow. Somebody cares who did this thing and and they’re? You know they’re going to be really happy about your work, they’re going to feel better about their instrument. Now, after we’ve cleaned the excess paraffin off, then we’re going to want to lubricate it any regular cork grease that comes with your with your clarinet that you go by the music store is sufficient. I prefer anything: that’s just a little waxy err, rather than you know, kind of like a soft lip balm consistency. But another thing that works is also regular, plain, unflavored chapstick. It doesn’t really matter what variety it is. I’M kind of convinced that the same manufacturer that makes cork grease and lip balm is the same one and they just have different labels, so you can use you can use cork grease as lip balm. You can use lip balm as cork grease put a small amount of the cork grease on here and kind of like when we put the glue on just kind of let the cork grease run in front of your finger. Put that a bit that bit on and then we’ll come in here and that just slides on just perfect, you want it to be easy to put on but able to be adjusted as you as you play on an on a clarinet, the center cork, the holes Of joints together, it needs to be fit somewhat firm and it’s not hard to put together, but when it’s together there should be no rocking. This needs to be rock solid. Otherwise, the adjustment that we have here across the joints won’t be stable. The cork that happens here on the the barrel again, it needs to be free enough that you can adjust it and then the cork on your mouthpiece. You want that to be pretty firm. You don’t want the mouthpiece to fall off in the middle of performing on the bail. You want this easy enough to put on and not fall off when you’re playing, but it doesn’t need to be really tight, just tight enough to hold the bail on so we’ve been covering joint corks. These principles apply to any woodwind instrument that uses this type of quirk. Oboes English horns: if you’re interested in learning more about musical instrument repair go online, do a search under band instrument, repair management, repair kits and don’t forget to check out our extensive educational resources at Army Field band.

Read More: How to play the clarinet (basics)

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