[ Ref. "Neatsfoot Oil as Leather Sealant" in 160616 MMDigest ]

Mr. Bullock offered one view of organ leathers and I would like to add
a little to the perspective.  As I recall, batches of leather would
turn out bad, or alternatively local environments would end up being
problematic.  I remember one company telling me that despite over 80%
of their instruments being electro-pneumatic, they had decided that no
organs going into a certain city would contain leather pouches until
they felt they had a better handle on what was going on.  Another
company never wandered too far from what they had always done --
they felt the other firms just lacked experience and good suppliers.

I am aware of the Organ Historical Society (OHS) report.  I am not
aware that pesticides, this-cides or that-cides were ever named as
problematic.  Regardless, the author represents that these chemically
alter the tanning process.  I can find none of this is the leather
industry literature.

By contrast, what I can offer is that with World War II the federal
government turned a lot of products, including leathers, into
commodities -- to allow for universal suppliers.  To that end, the
sheep herders that had flocks reserved for the organ trade became
untenable and their breeds were essentially phased out of the markets.
Further, since then the government has repeatedly tampered with the
tanning process to make it environmentally friendlier.  So, again
the regional techniques have been replaced with commodity techniques.
The need for pneumatic (gasometer) leathers went down dramatically.

In addition, as previously discussed, neither mink oil nor neatsfoot oil
[today] are the originally conceived natural products.  They have largely
been commoditized and synthesized.  Further, even petro-chemicals today
are not the chemical equivalents of what the modern name label would have
implied when we were developing a lot of the tools and techniques of the
mechanical musical trades.

Chrome tanning is often trumpeted as the champ of modern leathers.
In fact, it became popular around the time of the War Between the
States (the American Civil War, for the rest of you).  There are
disputes as to when the chrome-tanned leather is really what was tested
because, although it is often treated as a commodity, unless you know
the particular process, it may not be the old "chrome tanned" leather.

A further complication with chrome tanned leather is that it is
essentially no longer produced in most of the developed world.  In fact,
we make a lot of it in Pakistan and India, where the environmental
regulations are almost absent and we poison the workers and land with
hexavalent chromium.  (Watch the movie "Erin Brockovich", for those in
the States, if that sounds familiar but you don't know why you should
care.)

As to the Robert Morton leather, it is available in two flavors from
two suppliers (Leather Supply and Columbia Leather).  Leather source #1
implies that they have recreated the Aeolian/Morton leather.  They seem
to buy the skins, do some final post-processing and have a celebrated
product.  Ask them for details; it is late and I don't recall the
details right now.  Supplier #2 takes skins, adds sealants and dyes the
skin.  (Or, at least that is what I recall.)

I suppose that the real secret is that the Morton leather likely came
from the Russian suppliers north of San Francisco and is most likely
birch-tanned-and-oiled leather ("Russia leather").

For safety and environmental reasons I would never permit the use of
an industrial rubber cement.  These products are bad for breathing,
they are flammable and they have volatile organic compounds.  They
rarely work as well, for most of the uses, as their evangelists would
have us think.

The old-timers who taught me, last century, would frown mightily if
I ever applied a sealant _after_ the pouch had been formed.

Finally, I just bristle at the suggestion of using "baby powder"
which is not disambiguated from corn-starch, in a musical instrument.
I am pretty sure the author meant to say "use cosmetic grade, asbestos
free, talcum powder."  (Of course, I am tired and maybe being too
picky.)

For some interesting references:

https://archive.org/stream/henleystwentieth00hiscrich/henleystwentieth00hiscrich_djvu.txt 

Most of the heavier leathers used in musical instruments in America are
the seconds [rejected] from the auto industry, just in case you are
curious.

In closing, Tandy leather is a huge hidden supplier to a lot of leather
users.  And, they have leather cement:

https://www.tandyleather.com/en/product/tanners-bond-rubber-cement 

Wm. Grant Chapman
West Point, New York

 [ At https://www.bergmanlegal.com/talc-contain-asbestos/  --
 [ "Talcum powder (also known as baby powder) ... is obtained through
 [ mining mineral deposits, which are often inter-mingled with deposits
 [ of a type of asbestos known as asbestiform tremolite."  -- Robbie