[link redacted at request of site owner - Jul 25, 2015]

Aging of hammer felt, leather, rubber, cotton

John Hartman [link redacted at request of site owner - Jul 25, 2015] [link redacted at request of site owner - Jul 25, 2015]
Sun, 08 Feb 2004 20:42:12 -0500


D.L.Bullock wrote:
>This is also why the leather on hammer butts turns into powder and
> wears through to the felt underneath in many older pianos.  Expecting that
> deterioration is why I replace hammer butts on so many pianos.

Most likely any leather that is turning into powder is vegetable tanned 
leather.  Vegetable tanning leaves the leather with a high acid 
content,(tannin ?)that's why it always falls apart. The trap work on 
many grands have oak tanned cow hide and these are usualy in pore 
condition. High quality buckskin found on back checks and other action 
parts were oil tanned. Oil tanned leather on the other hand can last for 
a very long time.

John Hartman RPT

John Hartman Pianos
[link redacted at request of site owner - Jul 25, 2015]
Rebuilding Steinway and Mason & Hamlin
Grand Pianos Since 1979

Piano Technicians Journal
Journal Illustrator/Contributing Editor
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