 The Clarinet BBoard
|
Author: rfunes
Date: 2021-08-03 18:56
I was wondering how much leak a clarinet could have before it actually adds noticeable resistance or other noticeable problems (difficult articulation, and so on)?
I found a leak in my instrument (the Ab/Eb pad in the lower joint), and right now it is in the repair person for new pads and adjustments.
When I tested the lower joint, I closed all keys/holes and blew hard into the lower part of the instrument, and it was very leaky (one could hear clearly the air leaking from this pad), but this leak only manifested itself when I used a quite large amount of air pressure.
I wonder what can I expect after I receive the instrument back, hopefully completely air tight, should I expect a huge difference in resistance/playing characteristics, or just a small improvement?
Post Edited (2021-08-03 19:04)
|
|
Reply To Message
|
|
Author: kdk ★2017
Date: 2021-08-03 19:35
rfunes wrote:
> I was wondering how much leak a clarinet could have before it
> actually adds noticeable resistance or other noticeable
> problems (difficult articulation, and so on)?
Most minor leaks won't cause a noticeable problem - until you have them sealed and you realize how much extra effort the repair is saving you. People play on leaky instruments all the time and learn to overcome the extra resistance.
>
> I found a leak in my instrument (the Ab/Eb pad in the lower
> joint), and right now it is in the repair person for new pads
> and adjustments.
Was this the only leak you found? It's too low on the instrument to cause problems for anything except the 4 notes below it - E3-G3 and B4-D5 - but if it leaked enough, those notes could be nearly unplayable.
>
> When I tested the lower joint, I closed all keys/holes and blew
> hard into the lower part of the instrument, and it was very
> leaky (one could hear clearly the air leaking from this pad),
That's not the ideal way to test for leaks. If you blow hard enough, you'll overcome the spring tensions and blow pads open that seal perfectly well under normal circumstances. Sucking the air out of the closed-up joint to form a vacuum is a better DIY approach. A repair person might use a machine (like a Magnehelic), a leak light or a feeler gauge (or a combination) to measure and locate leaks.
> but this leak only manifested itself when I used a quite large
> amount of air pressure.
>
You probably just blew it open.
The best way (IMHO) to find leaks (others may prefer other methods), whether at home or in a shop, is with a feeler - cut a longish (an inch or a little longer) thin strip of thin plastic (I use leader tape from the days of reel-to-reel tape recording) or paper (e.g. cigarette paper) and cut it to almost a point at one end. Put it under a pad, close it, and feel the amount (or lack) of any tug holding onto the feeler. Do this at each of the four main points around the pad (12:00, 3:00, 6:00 9:00). The feeler should detect even resistance all the way around.
> I wonder what can I expect after I receive the instrument back,
> hopefully completely air tight, should I expect a huge
> difference in resistance/playing characteristics, or just a
> small improvement?
It depends on how sensitive you are to the difference and how much leakage was actually sealed up (and how competent the repair guy is). If there were a lot of little leaks all over, you'll feel a quicker, more secure response - if the music you play demands it. If only the Ab/Eb leak was fixed, you will only notice a difference on those notes below it, if the leak was serious enough.
Karl
>
>
> Post Edited (2021-08-03 19:04)
|
|
Reply To Message
|
|
Author: rfunes
Date: 2021-08-03 19:53
Thanks, I just want to add that by having another person just resting a finger over that pad, it was enough that it would not leak, even using the strong air pressure I was using to test.
Just the slightest touch of a finger over the pad was enough to seal it, which means the leak could be anything from a low spring tension to the pad itself.
Since the pad was not in a great shape, it will be replaced and the spring adjusted as well.
I will receive the instrument back this Friday, so I will post the results here. I am very interested to see how much this leak was actually impacting the playing.
Post Edited (2021-08-03 19:53)
|
|
Reply To Message
|
|
Author: kdk ★2017
Date: 2021-08-03 20:24
Are you only having the one pad replaced or is the tech checking the rest of the instrument?
Karl
|
|
Reply To Message
|
|
Author: rfunes
Date: 2021-08-03 20:33
The instrument in general has a few discolored pads, so it is going through a general check.
Post Edited (2021-08-03 20:34)
|
|
Reply To Message
|
|
Author: Paul Aviles
Date: 2021-08-03 22:58
I am completely in agreement with Karl that a negative pressure test is better for finding minor leaks. Positive pressure is great for exposing a poor spring tension.
The Eb/Ab key is a bit tricky. Since it is large, it blows open easily (playing conditions included). So I tend to make that key's spring tension just slightly more so than what balances with the other three around it. That said, you can still blow that open pretty easily.
To answer the first question last, if you have cork (or Valentino Masters) pads installed properly with good spring tensions, the clarinet will play with optimum power and resonance. If you'd previously had a leak, and then play on everything all tightened up, you'll REALLY feel and hear the difference.
...............Paul Aviles
|
|
Reply To Message
|
|
Author: Chris P
Date: 2021-08-04 01:01
Small leaks will increase the resistance and affect the response.
As well as the pads being a main culprit for leaks if they're damaged, porous, ill-fitted or not closing with enough pressure due to poor regulation or weak springing, the condition of the tonehole crowns are an important factor in how well any given pad will seal against it. Any small defects such as surface vessels, chips or nicks in them will cause a leak. Several small leaks will soon constitute to a significant leak and they will all need to be addressed. Low viscosity superglue is the best way to deal with leaks or imperfections, either with or without wood dust as a filler depending on the severity.
If all the pads are seating well and all tonehole crowns are perfect, both level and free from defects, other leaks can still happen which can be due to hidden cracks, natural flaws in the wood where large vessels can run into the bore from pillar holes, slots, tenons or any other countersunk features, beetle larvae damage (or 'worm holes') or manufacturing defects if tonehole inserts, speaker or thumb tubes haven't been glued in well or incorrectly fitted. With plastic instruments, sometimes there can be bubbles within the plastic as it was formed into the billet or during the injection moulding process and these bubbles only come to light once the toneholes are drilled or slots are milled.
Whenever any instrument is in for a service or an overhaul when all the keys are removed, it's always best to check all the joints are perfectly airtight without any keywork fitted by sealing up all the toneholes and one end of the joint, then doing a vacuum or pressure test to see how well each joint holds the vacuum or pressure, then the joint can be ruled out if it passes.
One way to pinpoint leaks is to seal up al the toneholes and ends of the bore, but fit an air hose into one end, then pressurise the joint and submerge it in water to see where the bubbles are emerging from. Then the leak can be dealt with by whatever method is best suited - most minor leaks can be sealed successfully by drawing low viscosity superglue into them.
In the olden days when dinosaurs once roamed the earth, they checked for leaks by blowing cigarette smoke into joints to see where the smoke emerged from. as well as the obvious smell of tobacco smoke that's not easy to remove, tar deposits can form where the leaks are and stain pads.
Sometimes things like metal tenon caps or socket linings can give false readings if they appear to be well fitted, but there could be a void under them to cause air to leak under certain circumstances. Again, superglue will wick deep into these voids and seal them up.
To conclude, superglue.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
|
|
Reply To Message
|
|
Author: kdk ★2017
Date: 2021-08-04 01:41
Chris P wrote:
> In the olden days when dinosaurs once roamed the earth, they
> checked for leaks by blowing cigarette smoke into joints to see
> where the smoke emerged from. as well as the obvious smell of
> tobacco smoke that's not easy to remove, tar deposits can form
> where the leaks are and stain pads.
The first local repairman I ever went to (ca. 1960) with my first wood Fontaine clarinet looked for leaks that way. That clarinet is now a lamp, but I think sometimes I still can smell the cigarette smoke when I pass it in my practice room.
Karl
|
|
Reply To Message
|
|
Author: Matt74
Date: 2021-08-04 03:36
If a clarinet is leaking at all it produces noticeable resistance, but as has been said, people play leaky horns all the time.
If it has been a while since it was adjusted, and they do everything necessary, when you get your instrument back it should be amazing.
- Matthew Simington
Post Edited (2021-08-04 03:42)
|
|
Reply To Message
|
|
Author: SunnyDaze
Date: 2021-08-04 13:53
It should definitely make a huge difference.
I've had single instruments repaired by several different people to try to track down problems, and the quality of the workmanship makes a massive difference. If you can find a really good repair tech, then the horn will be much much better, even than just being completely overhauled by a competent one.
The really good people always find leaks that I don't know about, which is always a huge surprise to me. I ask for one pad to be replaced and it comes back with six, and playing like a totally different instrument.
|
|
Reply To Message
|
|
Author: rfunes
Date: 2021-08-09 17:26
I got the instrument back, so I will update the final results here:
The leak is definitely gone. By doing the same test I did before, now I cannot have any air leak, even using a lot of air pressure. So I was not blowing the Ab/Eb pad open, it was really leaking before.
The resistance was reduced a bit, something around 15%. Which is a win, to be honest.
Post Edited (2021-08-09 19:16)
|
|
Reply To Message
|
|
Author: Bob Bernardo
Date: 2021-08-11 06:47
The horns shouldn't ever leak. I do my own repair work, but get any leak fixed right away.
Designer of - Vintage 1940 Cicero Mouthpieces and the La Vecchia mouthpieces
Yamaha Artist 2015
|
|
Reply To Message
|
|
Author: Chris P
Date: 2021-08-12 02:14
"The horns shouldn't ever leak"
No, they shouldn't leak, but they very often do and most wooden clarinets do from brand new.
The leaks may not be apparent, but they're still there to some degree as some instruments will leak more than others. You can't rely on wooden clarinets to have perfectly cut toneholes as wood will always have natural flaws and vessels that become apparent as soon as the cutter uncovers them and pads won't seal these natural flaws.
I've currently got a Yamaha YCL-CX in for a full overhaul and although the tonehole crowns are nicely formed with a flattened top to make them pad friendly (unlike the razor sharp Buffet ones), they have a LOT of vessels running across the crowns which I've had to fill in to be sure they're airtight once I install the new pads.
Anyone overhauling wooden clarinets ought to do this sort of work to ensure the pads they use will seat and seal perfectly on them. There are no excuses on not doing any tonehole work as it should be one of the most important stages of the overhaul, just like levelling toneholes when overhauling saxes regardless of make or model.
Plastic/composite and ebonite clarinets and wooden clarinets with their toneholes all bushed with plastic, ebonite or any other synthetic material should be the most airtight provided the tonehole countersinks have been cut nicely, the crowns are level and not damaged.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
|
|
Reply To Message
|
|
The Clarinet Pages
|
 |
.jpg){kind=small}
.jpg){kind=small}
.jpg){kind=small}
.jpg){kind=small}
.jpg){kind=small}
.jpg){kind=small}
