Key Lead Corrosion

[Kirk Beasley]

Salt air, if you live in CA, FL or HI.  Seal off the lead (e.g., with shellac)
from the air and the reaction is slowed dramatically.  I have found key leads
so swollen that I had to break keys in order to get them out of the piano.

Kirk

----------
From: 	owner-pianotech@byu.edu on behalf of jpiesik@arinc.com
Sent: 	Friday, June 28, 1996 12:21 PM
To: 	pianotech@byu.edu
Subject: 	Key Lead Corrosion

    Subject:  Corroded Key Lead

    What causes the lead in keys to corrode?  Why do some key leads corrode
    and others do not?  What, chemically/physically, is REALLY happening
    here?

    Why is it that some pianos only 20+ years old have corroded/expanded key
    lead while much older pianos have original key leads with virtually no
    lead corrosion evident?

    Is there a variation in the quality/purity of lead?  Is there a chemical
    reaction occurring between the lead and the "treated" wood in some key
    sticks?  Is it an oxidation process that is occurring as a result of a
    particular atmospheric environment?  Or, is it a by-product of the lead
    alloy that allows the corrosion to occur?

    What is the best and safest approach/method to correct non-functioning
    keys because the lead is so "puffy?"  Could one "seal" key lead to
    inhibit the oxidation process?

    I run accross this symptom periodically in various levels of severity.
    I suspect we will be seeing much more of this in the years to come.  Can
    anyone shed some light on this baffling (at least to me) subject?

    Thank you for your responses!

    John Piesik
    San Diego Chapter PTG
    JPIESIK@ARINC.COM