 The Clarinet BBoard
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Author: nron
Date: 2016-03-06 14:55
how long should a suction test last on the lower joint of a clarinet when looking for leaks?
I can get 15 or 20 on the upper joint but when it comes to the lower joint i get more like 5.
Got the same result after stretching rubber a couple of rubberbands over each of the the key cups to hold them shut.
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Author: Chris P
Date: 2016-03-06 15:04
Try to get as much as possible from the lower joint as the longer the suction holds, the better. The lower joint may not hold the suction as well as the top joint depending on the pads used (depending on how porous they are), but you should aim to get over ten seconds of suction held on the lower joint. The top joint is far more critical and most new clarinets won't even get five seconds.
You shouldn't have to resort to forcing the pads closed to get the suction as no-one plays with a gorilla grip. So check and adjust the pads so they seat well, then test the suction with normal finger pressure.
How are you stopping the tonehole chimneys? If you're just using finger pressure, then lick your fingers to create a better seal, or use Blu-Tack or silicone rubber bungs to seal them.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
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Author: Paul Aviles
Date: 2016-03-06 16:42
I think you get a better idea of the whole thing by trying other clarinets (or other overhauls) over time. For me, I want a nice intense seal upfront. When you initiate the negative pressure, you should feel the pull on your hand, fingers and lips. It should feel that way for a "moment" before you pull it away from your lips. And when you do pull away, you should hear a definitive "pop."
That said the lower joint is historically a bit trickier to get to the same degree (but can!). And as you have found, the correctness contact around the rim of the tone hole with the pad makes the seal, not the pressure per se. After just saying that, there is a delicate spring tension issue with the "Ab/Eb" pad. If that one is not taught enough, there is actually a bit of positive pressure when you play that will make that note and those below less resonant.
...............Paul Aviles
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Author: nron
Date: 2016-03-07 07:36
Ah, as I thought, this means I've got a problem somewhere in my horn :(
Thanks for the wet fingers tip too! Also, my horn is all leather pads except for the register key cork.
My thoughts are that there is a leaking pad somewhere because to me ![[D5]](http://test.woodwind.org/clarinet/BBoard/smileys/d5.gif) to long B and long C do not have any lag so lost motion or poor adjustment seem like a null factor. Bit surprised because every time I take the bell off I feel like the key work down there is at risk because of where I put my hands.
tonight I'll compare it to some friends horns of different makes and same makes to see how mine compares
Thanks
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Author: Tony F
Date: 2016-03-07 08:07
Your leather pads may be sealing well but still be porous. You can check this by putting a small piece of cling-wrap under the pads. Make sure that the cling-wrap is completely flat with no folds. The cling-wrap is thin enough that it won't interfere with the pad to tone-hole relationship but it will prevent the pad porosity being a factor.
Tony F.
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Author: Paul Aviles
Date: 2016-03-07 15:10
Or......
Depending on age, wear and maintenance, leather pads can dry up and lose their shape and/or crack. Leather pads should have monthly maintenance in the form of a quick treatment (such as running a strip of paper slightly damp with "Old English" furniture polish underneath it).
..............Paul Aviles
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Author: Chris P
Date: 2016-03-07 16:33
Do a spot test on leather pads with a wet cotton bud (or Q-tip) to determine if they're made with treated leather or not - if the leather darkens considerably when you wet it, then it's not treated (but has still been tanned to preserve it).
A lot of leather pads nowadays are made with plastic coated leather to make them waterproof and airtight. These won't change colour or stain as much as untreated leather pads and should be far less porous.
Poor quality ones can suffer with the plastic coating coming off the leather and sticking to the toneholes so the pads end up porous and it can take some doing to remove the bits of plastic coating debris stuck to the toneholes. So always use good quality leather pads or make sure your repairer stocks them.
Don't buy dirt cheap pads of any kind off eBay as it's a false economy.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
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