VERDIGRIS IS COPPER CORROSION, GRRRRRRRRRR!

[Susan Kline]

At 05:36 PM 7/29/2005 -0700, you wrote:
>VERDIGRIS is an oxidation of COPPER without COPPER it
>CAN NOT EXIST!!!!! In the felt, or the pin. Probably
>the pin. So what is the composition of pins today, so
>that it can't arise. SIMPLE QUESTION!
>Sheesh!!!!
>      Thump


The copper is still where it always was, in the brass core
of the pin. I would think that nickel-plated pins wouldn't be
as prone to verdigris as straight unplated brass.

I believe that the difference in today's non-verdigrised centers,
and non-Steinway old pianos without verdigris, versus Steinway and
a very few other good brands of pianos with TONS of verdigris, is
that Steinway dipped the flanges in tallow. Something about the grease
seems to encourage the creeping green crud, which we should consider
as we slather all kinds of lubricants on center pins, instead of just
repinning if they are sluggish.

Don't know why the grease makes such a difference, but it seems to.
Perhaps instead of waterproofing the center, as it was meant to, it
actually is hygroscopic? I also notice that verdigris is worse in damp
climates.

Susan