Corrosion on valve seats is becoming more of a problem than it was
20 years ago, possibly because today's valve leather has more acid
in it than previously.

Two years ago, I clamped samples of split suede cowhide, pigskin,
vegetable-tanned cowhide, white CPL, tan pouch leather, and maroon
kangaroo leather to a sheet of unlacquered brass.  Now, two years
later, verdigris is forming under every sample, refuting the idea
that any of these types of leather are immune to causing corrosion.

I didn't even try a sample of alum-tanned sheepskin because that has
been known to have a devastating effect on metal ever since I entered
this business in the 1960s.

G.J. Nikolas & Co., Inc., nearby Chicago in Bellwood, Illinois,
has been making industrial quality metal lacquer since 1890.  Their
product brochure states "We were the first to develop air-dry lacquers
for use on automobile production lines, and premiered this invention
at the 1911 World's Fair."  Customers have included Otis (brass
elevator panels), Lyon & Healy (harps), and many band instrument and
lighting product manufacturers.  We have used small quantities of
Nikolas #2105 clear lacquer on valve seats and other metal parts for
about 30 years with enduring excellent results.

I spoke with the owner of Nikolas a few years ago, and he said their
#2105 clear aerosol lacquer continues to be their best product for
this use.  If you need only a small quantity for several pianos, you
can purchase individual cans from Votaw Tool Co., a supplier of band
instrument repair tools and supplies ( http://www.votawtool.com ).
Nikolas' minimum order is a case of six cans.  Please don't bother
Nikolas for smaller orders, but if you need one or more cases, the web
site is http://www.finish1.com/splash.htm 

I'm interested to learn about others' experiences -- both good and bad
-- with ways of preventing leather-caused corrosion.

Art Reblitz
Colorado Springs, Colorado