Sources and Processing Thin Leather and Leather with a Spring In It, i.e., Hops
By John Speller and Timothy Patterson, forwarded by Darrell Clarke
Jody,
At the risk of boring those not interested in thin leather, here is some more detail which has been around the world a couple of times! I had passed on one of our postings to a colleague who restores organs and he passed it to his contacts in the U.S. I don't have an address for Columbia Organ Leathers, but the contact below might be able to supply it. Happy leather hunting,
Darrell Clarke
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Date: Fri, 7 Jun 1996 09:14:21 -0500
Sender: Pipe Organs and Related Topics <PIPORG-L@CNSIBM.ALBANY.EDU>
From: "John L. Speller" <jlspeller@stlnet.com>
Subject: Re: FW: Leather with a spring in it (ie, hops)
At 03:04 PM 6/7/96 CST, Peter Beames wrote:
> The Player Piano Co in Wichita, KS informs me that they now have a
> shipment of the very wonderful kangaroo pouch leather from Australia.
> This stuff is unbeatable. For those who don't trust sealants at all
> and yet want a tight thin pouch averaging .010 or less, this is the
> best there is, and you can't tear it.
This is quite true, Australian kangaroo is extremely sturdy, non-porous and unstretchable. The young kangaroos ("joeys") are particularly good. It is important also to know, however, the process by which the leather has been tanned. Alum tanned leather decomposes spontaneously at temperatures above 90 degrees, and so under some circumstances can have virtually no life at all. Chrome tanned leather has a fairly long life which is (within certain parameters of retained chrome content, etc., which can easily be tested for) to a large extent independent of how carefully the tanning process has been carried out. Vegetable tanning processes vary according to how carefully the process has been carried out. Leather which has been very carefully tanned by a vegetable process may have a life which equals or even exceeds that of chrome tanning, but these days one unfortunately one cannot rely on the process having been carried out with extreme care. This is why Columbia Organ Leathers currently exclusively purchases chrome tanned leathers from the tanneries. We have made several excursions into supplying Australian kangaroo, but have been unable to find a source which is consistently reliable or that can be obtained in sufficient quantity.
> I have not been able to locate decent zephyr skin, anyway.
Nor, I think has anyone.
> The pouch leather of the teens and 20's was taken mostly from herds
> of 2 yr. old Scottish sheep bred just for that purpose. Today, pouch
> leather is taken mostly from animals raised for food, and much of it is
> just too weak, since the animals are watered heavily and ranging is
> discouraged.
This is unfortunately true, and recent wars and famines in third world countries where most of the leather comes from. Farmers are less careful with their sheep than they used to be and the incidence of scars from wounds made by barbed wire (leading to holes in the leather) has been increasing in many places. All one can really do is to look for the best leather that is available. Much of the sheep used is "hair-sheep", or woolless sheep, found in the Caribbean and Africa. Recently we have been able to obtain some extremely fine hair-sheep from Haiti, a source which had previously been unobtainable for some years because of the civil war. This is available in thicknesses below 10 thousandths of an inch. Porosity is generally only a problem in ventil chests on pressures above 5", where the surface of the leather may require sealing.
The finest leather of all came from North Africa and was the so-called "Morocco" leather. A tribe there devoted their whole life to tanning leather by a complex vegetable tanning process which was carried out with infinite care and took literally years to accomplish. Unfortunately they were all wiped out in World War II.
> To give you an example of its weathering qualities, one needs to
> look no further than Duo-Art accordion pneumatics. It was the
> factory's idea to cover these in pouch leather, which, in our area,
> lasted about 50 years when exposed. After that, it disintegrated.
> When these were recovered with new pouch leather in the 60's and 70's
> and resealed with (you know what)-- rubber cement-- the new leather
> lasted between 8-15 years. Then you could stick your finger through
> it. By 5 or 6 years it was leaking like a sieve, anyway.
The 60's and 70's were, however, the low point. Though they may not be of quite the same quality as the leathers which were available in the 20's, the leathers which have been available since around 1985 are in fact superior to anything which was available between 1940 and 1985.
> He tells me that pouch leather is the only product in his line that
> is unavailable at the moment. He does have some in stock but it isn't
> ready for sale yet, due to machining difficulties.
This is the kind of thing I mean by saying that we have been unable to find a consistently reliable source to supply the leather in sufficient quantities. Rick Alabaster does, I believe, use a chrome tanning process and so if it is possible to obtain it it will probably hold up fairly well. The same cannot unfortunately be said of some of the other suppliers. Rick's leather can readily be recognized because it is dyed a maroon color similar to the old Aeolian leather.
In Rick's words "it ain't
>easy". We've also just had 4 years of drought so the skins aren't
>really up to scratch, so the problem goes on.
In other words the same problems of drought, famine, etc. which afflict the sheep skin are also afflicting the kangaroo.
So if you can get good kangaroo leather, go for it, but I wish you luck in obtaining it. I'm surprised no one has made any jokes about kangaroos having pouches,
John.
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Date: Fri, 7 Jun 1996 09:32:00 CDT
Sender: Pipe Organs and Related Topics <PIPORG-L@CNSIBM.ALBANY.EDU>
From: Timothy Patterson <timp29@popmail.skypoint.com>
Subject: Re: FW: Leather with a spring in it (ie, hops)
The Kangaroo leather I have received lately has not been up to snuff. It had many flaws.
Timothy Patterson <timp29@popmail.skypoint.com> |
(Message sent Tue 11 Jun 1996, 18:17:00 GMT, from time zone GMT-0600.) |
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