 The Clarinet BBoard
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Author: ruben
Date: 2014-05-16 10:54
Saxophone repair people use a light to find leaks in the instrument. If a pad isn't sealing properly, the light shines through the leaky pad. Is there anything stopping one from using this very effective method on clarinets? Obviously the light has to be small enough and mustn't heat up the wood. We are fortunate in having a lot of excellent repair people on this board and they certainly have an answer. How does or would this technique compare in effectiveness with the cigarette paper one? Thank you.
rubengreenbergparisfrance@gmail.com
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Author: Paul Aviles
Date: 2014-05-16 14:21
Substantial leaks on a Bb soprano clarinet can be too small to use a light. I have seen a few techs use a light on a bass but I wasn't too thrilled with the results.
The feeler gauge is the way to go.
..............Paul Aviles
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Author: Chris P
Date: 2014-05-16 14:26
The problem with leak lights and clarinets are the lengths of the toneholes and light will shine through skin pads (if used).
I do use a fluorescent leak light on saxes and bass clarinets as they have short toneholes relative to their joint thicknesses, but not on smaller woodwinds.
And now LED technology is offering very small but powerful light, these are being used more and more by repairers. Someone nearby has made several leak lights for all woodwinds, so I checked my piccolo (which I cork padded) with his piccolo leak light - glad to see it was as good as I hoped. I use feeler gauges for most woodwinds to check pad seating and regulation.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
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Author: Tony F
Date: 2014-05-16 14:37
Music Medic offer a low-cost flexible leak light. I find it quite useful, although the translucency of some pads make it less effective. It is not a replacement for traditional methods, but it is a useful addition to them. Apart from its use in detecting leaks, its an excellent way of inspecting the interiors of bores and tone holes.
Tony F.
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Author: rtmyth
Date: 2014-05-16 16:21
pressure test is better than light or vacuum, for me.
richard smith
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Author: saxlite
Date: 2014-05-16 16:49
I have found the found the 6" Music Medic LED light excellent for setting the timing on the low E-F crow'sfoot adjustment. You can clearly see if the two pads hit the tone holes at the same time ( or not ). I agree that the light is not useful for other pad work.
Jerry
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Author: Chris P
Date: 2014-05-16 17:47
If anything, you want to set up the crow's foot so the E/B pad closes after the F/C pad instead of exactly at the same time. The F/C pad should close with slightly more pressure than the E/B pad to ensure you can play E/B with just the LH lever. There's the amount of flexing in the keywork which you have to account for when regulating linked mechanisms - work with the torsion in mind rather than going by the book. On larger instruments with long key rods (bass clarinet, saxes etc.) this is important.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
Post Edited (2014-05-16 17:49)
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Author: Paul Aviles
Date: 2014-05-16 21:12
Whoa Chris, I think you really hit the nail on the head with the repair I had done on a bass clarinet. NONE of the torsion was taken into account......I think he just might have been in a hurry.
..................Paul Aviles
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Author: Steven Ocone
Date: 2014-05-16 23:44
The leak light is my primary tool for leveling a pad. I also use a feeler gauge on every pad. Like most methods, you can get anywhere from great to awful results using a leak light, and it might not match all padding styles. I use a magnehelic pressure gauge to check my results. Once a pad has an impression the leak light is less useful.
The synthetic pads tend to have a lot of "drag" on a feeler gage (I use .0005" mylar, cut in a narrow strip). This is where a leak light shines (sorry about the pun).
A leak light is also a quick way to spot problems with the pad or tone hole without disassembling the instrument.
Steve Ocone
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Author: David Spiegelthal ★2017
Date: 2014-05-17 00:10
One of the many advantages of using leather pads on soprano clarinets as I do, is that the leak light becomes a perfectly useful device for finding leaks. With the traditional bladder (skin) pads, as Chris P pointed out, the leak light is not very effective and feeler gauges or (better yet, as Steven suggests) thin pieces of feeler material must be used.
Still, with some of the pads on any clarinet, part of the circumference is blocked from view by adjacent mechanism, so even with opaque pads the leak light is not a 100% solution. So, start with the 'suck test' and the 'blow test' and if you sense a leak from either/both of these, go to the leak light or feelers.
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Author: Caroline Smale
Date: 2014-05-17 00:25
In my view the feeler guage is by far most accurate method. It not only allows one to test every angle around the pad but also, in sensitive and trained hands, allows sensing the exact pressure at back and front of pad when operated individually and, where appropriate, in conjuction with other pads.
For a top quality job it isn't always an exact even pressure all round that is initially required but a very subtle difference front to back to allow for a little settling as the new pad compresses very slightly in first few days of use.
My preference even on saxes is the feeler.
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Author: Chris P
Date: 2014-05-17 00:44
Repairers once used cigarette smoke to check for leaks in the dark ages. It stinks and the tar from the smoke stains pads where the leaks are.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
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Author: Gordon (NZ)
Date: 2014-05-17 15:57
I would not trust a leak light for clarinets, even with brown leather pads.
I know from using a leak light on saxes, that if there is not a lot of light available to escape past a pad, then I miss small leaks.
Small leaks matter.
By the time a light in a black, light-absorbing bore travels a significant distance up a black, light-absorbing tone hole, there is very little light left bouncing around to change direction and slip between a tone hole and a pad. Not enough for reliable leak detection.
As for translucent pads, there is too much light already diffusing past the pad to definitively detect small leaks which have a fraction more light slipping past. EVen with a shiny bore and shallow tone holes, as on a flute, very few if any top technicians would would use light for detecting small leaks.
What I don't like about synthetic pads in general, for normally-open pads, is that the surface remains microscopically bubbly, i.e. irregular - more irregular than traditional fel/membrane pads. When the pad is closed, these bubbles must be squashed flat before a reliable seal is effected. So the player has to press keys harder. This especially shows up for the larger tone holes that have a larger contact area with the pad, hence require more force to squash the bubbles.
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Author: cyclopathic
Date: 2014-05-17 23:17
IMHO light is one of the tools you'd use, not the "method" and it is not opposite to other means.
I use combination of leak light, filler gauge, blowing (and rubber bands on lower joint) to get it tight. As Norman mentioned light isn't as precise as filler gauge, but it helps to identify problem quickly (ok you have to use dark room, give you that). Light is great on RH side keys, but some pads like one under A key aren't easily identifiable with light, but better with feeler. And low E and G just easier to rubber bend to get them seated (sprung F and G# usually do it by themselves).
Either way light or feeler the trick to close pad as lightly as possible, some issues aren't detectable with meat fingers.
The ultimate test is to plug bell and give it blow, that helps to find remaining issues (weak/turned springs, leaky corks, cracks, etc)
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Author: Gordon (NZ)
Date: 2014-05-18 07:15
Another reason I prefer using a feeler (along with blow-pressure-test) is that this checks for equal closing pressure right around the tone hole edge, and on separate tone hole edges for linked keys. A leak light checks for simultaneous contact of areas of pad(s) with the tone hole.
The two are not necessarily compatible, especially for keys with long, somewhat flexible linkage parts, as for F/C-E/B. (And for instruments with very large keys, eg bass clarinet, the prefect compromise is vital.
As far as sealing is concerned, the latter, equal pressure condition, is more important.
Also, for many keys on a clarinet, visual access to check for light leakage is not possible right around the pad.
I think highlighting the required accuracy of all this is important. Differences in closure against tone holes of 0.001 mm (0.0004") constitutes a significant leak.
Post Edited (2014-05-18 07:16)
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Author: clarnibass
Date: 2014-05-20 10:06
I use both a leak light and feeler (plus blowing/sucking, magnehelic machine). The leak light is problematic with some pads. It is also problematic to see the sides of some pads because of the outer tone hole walls and sometimes keys block your view from other keys.
The leak light is excellent at finding some big leaks very fast, which is how I use it mostly, but not for finidng every leak or doing all adjustments. It's also sometimes good at finding tiny leaks that the feeler can't feel because they are significantly smaller than the width of the feeler.
Although it tears more easily and not so resistant to getting wet, I still prefer rolling papers for feeler in comparison with the other feeler matirials mentioned in this thread, which I've also tried.
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