wood, wax and mold

[Carol R. Beigel]

>I'm not ready to accept the assertion that piano felt verdigris is a mold
until
>a qualified plant biologist (proper term? surely not a mycologist --
>moldologist??) is coerced into identifying the species.

Patrick - I will concede that before I became a piano technician, that
everything I learned about mold, mildew and other assorted furry growths
came from my refrigerator, but I was referring to a specific lecture given
at a convention.  I believe this was presented by a piano manufacturer that
had used a microscope and was showing slides of a felt bushing that had been
treated for vertigris.  The slides showed severe damage to the wool.  The
gist of the lecture was 1) vertigris was a mold, 2) that even if you killed
it, it still came back, 3) it attacked the parafin used in the wool bushing.

This information is crucial to how we treat vertigris.  If you just use
carbona, and clean the vertigris as best you can, and then repin, you are
still repinning a damaged bushing and the problem can reoccur.  If you
rebush the flanges, the parafin may have creeped into the wood, and will
reinfect the new wool bushings. What I had observed on my cedar siding was
that a black, vertigris-looking stuff was growing on wood I had
inadvertently treated with  parafin.

Although not clear in my post about my cedar siding, and I apologise for
that, my concern is really about how dangerous a substance parafin is to use
in pianos.  Since I never observed anything growing on the parafin my
grandma used in sealing her jelly jars, I am thinking that this is a wood,
wool and parafin reaction.  Parafin is also an ingredient in soap.
Rebuilders were told to used soap to lubricate the screws that hold the
pinblocks to the plate.  Since then, at least one manufacturer has found
that the soap leeched into the pinblock and loosened the tuning pins near
these screws.  In the few pinblocks I replaced, I noticed the screw holes in
the old blocks were black, and often furry.

I don't think we need a botanist's opinion to determine whether the green,
black, pink or white stuff we find in pianos (or refrigerators) is a mold or
corrosion.  I don't think the black fur I find on action centers is the same
thing as the black stuff on key bushings;  the material is being damaged
nonetheless.  The circumstances that cause corrosion can be just as varied
as those that cause "growths".  One instance that comes to mind is that a
piano manufacturer once changed their spring rail felt from red to green.
Very soon they were beseiged with complaints that the hammer butt springs
were breaking.  Turned out that the dye used to make the felt green
contained a chemical that was very corrosive to metal.

>I, will, however, suggest that we don't perpetuate "theories of piano
>center verdigris" without proofs better than "I seem to recall that
someone......

.. and Patrick, since aeronautical engineers cannot, can you prove that
bumblee bees fly?  :)

Carol Beigel