 The Clarinet BBoard
|
Author: Koo Young Chung
Date: 2007-06-15 05:34
What is the best method for testing leaks?
It seems that if you suck strong then small leaks will be closed.
And if you blow hard then closed pads open.
What do pros use to pinpoint the leaks?
|
|
Reply To Message
|
|
Author: jmsa
Date: 2007-06-15 07:08
The MAG leak machine works best to detect even the smallest leak.
jmsa
|
|
Reply To Message
|
|
Author: rtmyth
Date: 2007-06-15 13:32
Your ears can be pretty good at it if you know your instrument. Also, I check the cork pads occasionally under 3X to see they close completely. The best? I defer to the other comments.
richard smith
|
|
Reply To Message
|
|
Author: rmr25
Date: 2007-06-16 00:02
I've found the best leak tester to be tapered rubber plugs that fit both upper and lower joints. One plug is solid and goes in the bottom opening of the joint; the other has a hole in it that goes in the top. You just close all the finger and key openings and blow through the upper plug; the leaking spot is found immediately. I got my plugs at Votaw tool Co.
|
|
Reply To Message
|
|
Author: Chris P
Date: 2007-06-16 13:26
Do both tests - the suction test and the Magnehelic test.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
|
|
Reply To Message
|
|
Author: Paul Aviles
Date: 2007-06-16 13:37
I think there may be two trains of thought here. One is just the check before assembling the horn to get a rough idea if you are "all-systems-go," and the other is tracking down a REAL PROBLEM.
Suction covers most bases quickly, I just hold my available palm over the "other" end. The bottom joint can stand a bit of positive pressure to ensure that the Ab/Eb lever is not too loose (I think this could be a hidden problem for many out there).
Now, if you have a nasty leak and can't find it right away, the method I resort to as the LAST resort is taking off ALL the keys, covering the holes with small swaths of tape (plastic or duck) and then replacing the keys one at a time from the top down. This method WILL find the leak. It's just a bit of a pain.
.............Paul Aviles
Post Edited (2007-06-16 13:37)
|
|
Reply To Message
|
|
Author: Chris P
Date: 2007-06-16 13:53
Same sort of thing as Paul does to determine exactly which pad is leaking, but I use Blu-Tack instead of adhesive tape.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
|
|
Reply To Message
|
|
Author: Gordon (NZ)
Date: 2007-06-16 15:06
"And if you blow hard then closed pads open."
To diagnose if there is a leak, adn this happens, it means you are blowing too hard, &/or springs are poorly adjusted.
AFTER you have determined that there is indeed a leak, then blowing this hard can often quickly indicate which pad is the most troublesome one. When you have found this most troublesome one, squeeze it tight shut while testing, to see if this stops the leak. It often does, in which the diagnosis is quickly confirmed.
Just quick methods which work MOST of the time.
|
|
Reply To Message
|
|
Author: bmcgar ★2017
Date: 2007-06-16 22:37
Seconding Chris P's post, the best leak test is all of them.
|
|
Reply To Message
|
|
Author: Wes
Date: 2007-07-02 19:08
In desperation, if all else doesn't find the leak, one can plug the ends with a hose to one end and hold it under water, watching for bubbles at the leak site. It is preferable not to do this test as the water gets corks, etc wet and the instrument will have to dry off. Yet, it can sometimes find a stubborn leak. It has also been used on oboes.
One can sometimes find minute leaks in cork pads and chips in tone holes with an eye loupe. Good luck!
|
|
Reply To Message
|
|
Author: EEBaum
Date: 2007-07-02 23:16
Take a thin strip of paper (I think techs use a certain kind, but I forget what it's called), put it under a key you think might be leaking, and hold the key down. If you can pull the paper out easily with the key down, the key isn't sealing properly. Try it at a couple different angles.
-Alex
www.mostlydifferent.com
|
|
Reply To Message
|
|
Author: Jack Kissinger
Date: 2007-07-03 00:04
Getting the corks wet isn't that much of a problem. Soaking all your pads is.
1. If the suck test fails, there is a leak.
2. If the blow test succeeds, there is no leak.
Therefore:
If both tests fail, there is a leak. (By 1)
If both tests pass, there is no leak. (By 2)
The situation where (1) fails and (2) succeeds is not possible. (In theory )
If (1) succeeds and (2) fails, there may or may not be a leak. (1) may succeed where a leak is present because a leaking pad has been sucked shut. (2) may fail where there is no leak because above normal pressure has forced a pad open. In this case, the culprit is usually a pad normally held closed by a spring. In any case testing the pads with a piece of cassette tape may be more efficient (and effective) than removing all the pads and replacing them one-by-one. Open the pad (if necessary), slip a piece of the tape into a tone hole, close the pad and pull the piece of tape gently, noting the resistance. (If there is no resistance, you have found a leak.) Then open the pad, slide the tape a quarter of the way around the tone hole (or less, if you want to test every part), close the pad and again pull out the tape. If you have good resistance all the way around, there is probably no leak (unless the tone hole or pad are damaged).
Best regards,
jnk
|
|
Reply To Message
|
|
Author: Paul Aviles
Date: 2007-07-03 00:38
Hey Jack,
I could not disagree more, and here is why: I had at one time adjusted down the spring tensions to the "Nth" degree in an attempt to speed up technique. I actually played on horns adusted like that for a year or more. It was not until I played on some loaners I was abliged not to tweek that I realized how much more solid the bottom end of those horns were (E,F, G and the corresponding clarion).
After much additional fidgeting, I realized that the Ab/Eb key (right pinky) must have a bit more spring tension than what one may think necessary. Air pressure generated by fairly moderate playing levels can actually start to raise this key (something that one cannot test with a feeler gauge).
Now I do concede that many of the keys with smaller cups (slivers, sidekeys, octave, C#/G#) can be left quite loose but then you may run into the problem of just not having enough tactile resistance to encourage proper technique.
This is where discussion becomes wholey inadequate because determining proper spring tension is a true art. All I can add to this is that one needs to experience a fully Brannenized horn (or worthy repair wizard equivalent) to know what I am talking about.
Suffice to say that both positive and negative tests are necessary and wholey complementary.
...........Paul Aviles
|
|
Reply To Message
|
|
Author: Jack Kissinger
Date: 2007-07-03 04:02
Paul,
I'm sorry, I guess I'm dense. I don't understand what you're saying here. In fact, it's not even clear to me which part of my post you're disagreeing with. I didn't say anything about adjusting spring tension (or, at least I can't find anywhere that I did). I was simply trying to summarize the quick and dirty ways to determine if a joint has a leak that others had already identified. I didn't really address the issue of pinpointing where the leak is. Note that I qualified my comments about the feeler strip to limit them specifically to the situation where the suck test succeeds and the blow test fails -- a situation where it is impossible, based only on those two tests alone, to determine whether or not there is a leak somewhere. Impossible because, without further tests, one cannot know whether sucking is closing a small leak or blowing is opening a key whose spring tension is sufficient to keep it closed during playing.
Three frequent causes of a leak that I mentioned in my post (there are others) are: (1) a pad that is not properly seated, (2) a pad that is seated properly but has insufficient spring tension to hold it closed under maximum "playing" air pressure. (3) a damaged tone hole (or pad).
I mentioned above that the "feeler strip" may not find an imperfection in a tone hole or pad (which may be too small to affect the "wide" feeler's behavior). Careful inspection of the tone hole and pad (which may require removing keys) is probably the best way to find that kind of problem.
I'm willing to concede that the "feeler strip," while useful for finding an improperly seated pad, is not foolproof for finding a spring with inadequate tension (because the pad may or may not be properly seated). But it can indicate if the pad is properly seated. (In which case, the suck test is not the problem.) And before I take all the keys off and start sticking duct tape all over my horn, if I suspect a loose spring (and, at least on the lower joint, I should have a pretty good idea of where the problem pad is because of the symptoms I'm seeing), I will do what Gordon suggests, try clamping the suspicious key and then repeating the blow test. If it now succeeds, I know that the key was being blown open by the test and now the fun begins because I still don't know if it is being blown open when the instrument is played.
So I don't see where the disagreement is. My points really aren't inconsistent with yours. Your message addresses the issue of finding a specific difficult leak. Mine doesn't address that issue. Rather, the first part simply summarizes the basic logic underlying the suck and blow tests. The second part simply suggests some other easy things to look at in the one situation where the combination of outcomes from those two tests is inconclusive -- things to try before taking of the keys. And you say yourself that taking the keys off is a "last resort" -- a comment with which I totally agree.
Actually, the primary objective of my original message was to suggest that, unless one has Valentino or Norbeck pads, the "immersion test" is a recipe for disaster, whether it works or not. Another test that I'm personally glad has fallen out of widespread use is the "cigarette smoke" test.
Best regards,
jnk
Post Edited (2007-07-03 04:06)
|
|
Reply To Message
|
|
Author: sherman
Date: 2007-07-03 15:16
Perform the cadenza from Le Coq d'Or, or Peter and The Wolf. If there is a loud noise and you're fired, you'll know.
|
|
Reply To Message
|
|
Author: Paul Aviles
Date: 2007-07-03 15:30
Marcellus used to end his Summer masterclasses with a session where he played recordings of the well reknowned going down in flames. One of his favorite examples was one of Ralph McLane getting impaled on the tree as the cat in Peter and the Wolf.
Funny, I have never been in such a heated debate where two people are in such utter agreement. Thank you. That was indeed funny.
But seriously DON'T use Valentino pads.........they SUCK (they pass the "suck" test with flying colors).
............Paul Aviles
|
|
Reply To Message
|
|
Author: rtmyth
Date: 2007-07-15 14:24
Within the clarinet the air pressure is lowest at the bell and highest at the barrel. thus leaks in the upper joint are more likely to cause problems than those in the lower section.
richard smith
|
|
Reply To Message
|
|
Author: Paul Aviles
Date: 2007-07-15 17:05
Dear Richard,
I realize that pure physics cannot be refuted, but just try adjusting the spring on your Eb/Ab key to a rather light degree, then honk away on your low chalameau. Now try adjusting that spring to a rather taught degree and try the same honky business. You should encounter a rather marked difference in the solidity of your sound.
.............Paul Aviles
|
|
Reply To Message
|
|
The Clarinet Pages
|
 |
.jpg){kind=small}
.jpg){kind=small}
.jpg){kind=small}
.jpg){kind=small}
.jpg){kind=small}
.jpg){kind=small}
