key lead corrosion
Sat, 29 Jun 1996 22:16:25 -0400

<What causes the lead in keys to corrode? >
< a by-product of the lead alloy  allows the corrosion to occur?>

I am new to the list, but let me jump in here because I have worked with
lead, and alloys of lead in several different disciplines.

Pure lead is very inert, -dump it in water and 10 years later  it is
essentially the same, only the slightest sulfide coating- generally. Hey, -
that is why they used it in plumbing since the days of the Roman empire.

Alloy the lead with other metals, like antimony, tin, bismuth, etc. - and you
have a solid battery (dissimilar metals with different potentials)  that will
erode itself to swiss cheese  in a few weeks in water. Humidity will also
affect this alloy by eventually causing a white lead oxide.

A Test ------ pure lead is very soft, even a dull knife can cut off a shiny
chip easily.   If the lead is alloyed, the hardness increases considerably, a
knife will chip off a crumbly piece, and the surface will be  gray, not
mirror shiny.

<Why do some key leads corrode and others do not? >

I suspect that action makers used about the cheapest lead weights they could
get, which were probably old contaminated linotype slugs from printing
plants. ( 5% tin, 13% antimony, rest lead, with copper as a contaminant.-
they alloyed for hardness to make type print longer.)

 <Is there a chemical reaction occurring between the lead and the "treated"
wood in some key  sticks?>

I doubt it, unless the keys were wet.

 <Is it an oxidation process that is occurring as a result of a particular
atmospheric environment?>

Possibly a little, but not with pure lead weights.

<What is the best and safest approach/method to correct non-functioning  keys
because the lead is so "puffy?" >

Shave the excess off with a sharp chisel, -being careful not to eat the

<Could one "seal" key lead to inhibit the oxidation process?>

Sure, a swipe of paint ot varnish should do it. I used to sandblast the
oxidized key leads ( because I had a sandblaster setup) - and then put a spot
of varnish on them. You can just varnish the oxidized leads with a thin
mixture that penetrates the oxidation and then hardens up,- trapping the evil
oxides in place.

Random thoughts,
Bill Simon

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