Klarinet Archive - Posting 000236.txt from 2001/04

From: "Gordon Palmer" <gordp@-----.nz>
Subj: Re: [kl] Pads: Single versus Double Bladder (It does not matter)
Date: Thu, 12 Apr 2001 10:20:05 -0400

1. I have some doubts about the significance of you tubing suck test. I
think the leakage will be at the seal with the tube rather than through the
skin. Under a microscope the thin brass would be straddling valleys in the
skin. On a clarinet the contact area with the timber is far greater so the
situation is very different. But yes, you have a point re discardiing
porous pads, but perhaps your test is measuring smoothness of the surface
more than porosity.

2. Can you quantify the "3 times the normal thickness". I have no idea what
the 'normal' thickness was in Moennig's day. If it is much thicker than
Music Supplies' "special thick bladder" from where is it obtained?

3. I think there is a good point re re-using old felt for stability, but the
replacement alignment in the key cup would have to be perfect. I would
prefer to use a new FIRM felt pad, e.g. Lucien Delux, or any make using
modern treated felt materials that do not respond to environment changes.
Partly because pads that have become very hard are noisy, partly because of
the greatly increased time for the repad, and partly the risk of
misalignment of that compressed line with the tone hole edge.

4. You mention "newer, softer felt". Several grades of felt are available
Music Supplies, including several thicknesses (and hardnesses if requested)
of pressed felt.

5. As far as I recal, O-rings seal far better under compression than vacuum.
I think similar principles apply to this vacuum testing, and I think a
squit-a-mouthful-of-air test is possibly more valid.

6. If I do a compression test with wet fingers I have to push unnaturally
hard for the air not to bubble out past my finger print grooves. Did
Moennig, unlike most repairers, have very smooth, soft skin?

7. I suspect that with that air trying to get in and out of slow leaks
thousands of times per second, the effective difference between a slow leak
and no leak is nill. Let's look at a model of what is happening: Just
imagine a thirty foot corridor, jam packed with people (i.e. the air
molecules) leading from a room also packed with people. Now all the people
in the corridor stand still while those in the room alternate, trying to get
in the room and trying to get out, changing every second. Surely the guys
at the other end of the corridor will not be shoved at all, irrespective of
whether the corridor is 3 ft or 4 ft wide.
I think suck testers sometimes enter a fanatical realm of unreality.
But yes, I'll try a suck test, with grease on fingers or corks in tone
holes, on the next plastic clarinet I repad. I wouldn't want air seeping
past fingers or through wood grain to interfere with my test! I think your
comment on new clarinets not holding a long suck test may have more to do
with the derteriorating quality of available timber.

Gordon

----- Original Message -----
From: <Sfdr@-----.com>
Subject: Re: [kl] Pads: Single versus Double Bladder (It does not matter)

>
> The quality of the fishskin is far more important than the thickness
of
> it. One can find thick porous fishskin as well as thin porous skin. An
old
> twist top lipstick holder works quieter well for testing 17mm pad seals.
You
> can also buy brass tubing form a hobby shop and cut it into 3 inch
sections.
> for clarinet you will need 10mm, 12mm, 16mm, and 17mm diameters.
> Place the brass tubing against the pad face and draw a vacuum with
> your lips as if you are sucking on a drinking straw. the pad should hold
for
> 30 seconds. If not, throw it away as it will only cause you problems with
> sealing. I watched Hans Moennig test pads this way. Out of 100
commercially
> produced bladder pads he only used 10 of them. Although he used
commercial
> double skinned treated pads for student Buffets, For Professional players,
He
> made his own double skinned pads with extra thick fishskin (3 times the
> normal thickness). He once showed me a pad that had been used for 35
years
> and it was still sealing tightly.
> Regarding the felt, when one of the hand made pads tore, Mr. Moennig.
> Would always keep the old felt and cardboard and recover them with new
fish
> skin. He said that the older felt (Pressed Felt) was already compress and
> was much more stable that the newer softer felt (woven felt).
> The ultimate pad test is the number of seconds that the instrument
will
> hold a vacuum. Using cork pads the upper joint, the clarinet of Robert
> Marcellus held a three Minute Vacuum. With the handmade bladder pads the
> lower joint held a 75 second vacuum. I have never seen a new clarinet
that
> would hold such a tight seal.
> How many seconds do you get with the single skinned pads?
> Just Curious,
> Alvin Swiney
> Affordable Music Co.
> www.corkpad.com
>
> In a message dated 4/11/01 6:29:16 PM Central Daylight Time,
gordp@-----.nz
> writes:
>
> << I import my clarinet pads from Music Supplies in Italy, "the worlds
largest
> pad maker". One of their lines is "Mypads", which I think US imports. In
> fact many of the pads in US probably come from this supplier. Their range
> includes "single thick bladder" along with the more common "double
bladder."
>
> Many years ago I did some measuring and found the single bladder to be
about
> 1.5 times thicker than the membrane doubled on the double bladder pads. I
> wondered which was preferable.
>
> Let's assume that the pads are not going to be wrecked by zealous wiping
of
> them or abrasion at the edges. Through normal use the first sign of of
pad
> 'death' is a cut or small hole along the 'seal circle'. When this first
> starts on a clarinet the pad still seals on the tone hole because a
> significant area is in contact with the timber. The first problem that is
> likely to emerge is that the pad absorbs water through the cut or hole,
> swells, and stops sealing on account of this swelling. However this water
> absorption is the first problem with a dying pad only for SINGLE bladder
> pads....
>
> When the first layer of a DOUBLE membrane pad cuts through the loose
> membrane tends to wave about in the vibrating air, vibrating against the
> tone hole as the key is opened, and maybe still vibrating against the
second
> layer when the key is open. This can happen even though the second
membrane
> is making a good seal when the pad is closed. My point here is that there
is
> effectively only one thin layer to damage before the pad needs replacing.
>
> So the original question becomes: Which is preferable:
>
> a). A double bladder pad that effectively is dead when the first THIN
skin
> cuts through.
> b) . A single THICK bladder pad that dies when the THICK skin is first
> punctured and absorbs water.
>
> Because the thick bladder presumably takes considerably longer to
puncture
> than a thin bladder, the single bladder pad could be expected to last
longer
> than the double bladder pad.
>
> I therefore made my decision to use single thick bladders and have not
> regretted it. The pads I use last for many years.
>
> I would be interested if there is something I have missed in making this
> decision. There must surely be some valid reason why double bladder pads
> have caught on as the standard. Or is it just that the name makes them
SOUND
> as if they would be better.
>
> I might add that it seems even some top makers are lowering themselves to
> sometimes using very thin, brittle, single bladder pads which die in a
year
> or two.
>
> Gordon
>
> >>
>
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