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[BKARTS] Red rot (was dry rot)

Tom's answer is correct as far as it goes.

During the late 19th c. many people became aware of the problem
of red rot in leather (book bindings, leather harness, etc.) and
in 1905 a major research report was published in England which
attributed this problem to the use of sulfuric acid in one or more
stages of the production of leather.

Acid, however, seems to have been only one part of the problem.

In 1914 the U.S. Bureau of Standards published paper No. 34,
"Determination of Ammonia in Illuminating Gas" by J.D. Edwards.

Remember, at the time electric light was just coming into being and
homes/libraries were illuminated by candles, whale oil, kerosene,
or gas.  Illuminating gas.

Ammonia is at least as agressive as sulfuric acid, but in the opposite
chemical direction.

Sulfuric acid dehydrates and shrinks fibers in paper and leather.
Ammonia enlarges and softens fibers in paper and leather.

The combination of acid and alkali (sulfuric & ammonia) in the presence
of moisture creates salts.  Salts are mobile when damp and hard when they
dry out.

In leather, this means that the fibers are dehydrated by the acid, enlarged
and softened by ammonia, and disrupted by salt formation.

The leather powders away.  Softly, with grit.


>(snip) There also seems to have been some confusion with "red rot"
>in leather, another specific form of chemical decay: this slow but
>unstoppable reduction of the leather to reddish powder is caused by
>residual sulfuric acid from the manufacture of leather....
>Tom Conroy

Thompson Conservation Lab.
7549 N. Fenwick
Portland, Oregon  97217

503/735-3942  (ph/fax)


"The lyfe so short; the craft so long to lerne."
Chaucer  _Parlement of Foules_ 1386

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