Steinway hammers

[Roger Jolly]

Hi Jory,
        Thanks for your imformative post, my chem 101 is a little rusty
from 30yrs ago, there is nothing to for give re: intrusion, if we can't
stand correction we should not be on the list.

  However, having had experience at looking at doped hammers in many
different areas of the Continent, the fact remains that the acrylic/acetone
mixtures of hardeners exhibit the phenomenum of over hardening in low RH
climates in a relatively short space of time, if as you say the mixture is
not hydroscopic, I would love an broader explination.

  Your point on the lanolin is well taken. However the modern bleaching and
high temperatures used today gets rid of most of the lanolin, the old cold
pressed hammers had a slight yellow tinge, (lanolin) but most modern
hammers are pure white. It's been a theory of mine that the loss of the
lanolin has been the main cause in the loss of elasticity in modern
hammers.  This was backed up several years ago when I had a friend of mine
run Gas Chromatography samples on a 40yr old Baldwin cold pressed hammer in
comparison with an Imadegawa sample. The Baldwin sample had a high
concentration, the Imadegawa just trace amounts. The explanation I have
recieved from a manufacturer when I challenged them, is that pure white
hammers look better, and therefore implies better quality. The hot pressing
is a production cost factor, more than a quality issue. I'm sure Del could
add to this. Since we are both cold press junkies.  One run on only 2
samples is hardly a good test, but it is enough for me to hold to this
belief untill a better explination is forth coming.

  Modern key tops do have plasticers added, but the formulas are constantly
changing. Mid 70's to mid 80's many north American companies had key tops
showing half moon cracks, just from this type of problem, Yamaha had a
problem with yellowing on ivorite in the early productions, Now comes the
big question, if these products are so stable why would these changes
occur? If volitiles were not constantly being given off, these problems
would not happen. IMHO  Both of these problems only became apparent after
several years, and again it was more prevelent in dry climates.

  I enjoyed your post, at least it has taught me to be more careful to
check before I speak.

Regards



>Forgive the intrusion, but I feel I must correct some of this...
>
>Alcohols are organic compounds with a -OH group bonded to a carbon atom.
Since Acetone (aka Dimetyl Ketone, Metyl Ketone, 2-Propanone) has the
chemical formula (CH3)2CO and therefore has no -OH group, it cannot be an
alcohol.  Chemist might classify it as a Ketone.  Lay people would call it
a solvent.  Also, it's not really hygroscopic.  Since its vapor pressure is
very high (which is why it's used) it generally cannot absorb moisture
without vaporizing.
>
>Lacquer thinner is often denatured alcohol.  Pure ethyl (grain) alcohol (a
popular intoxicant) is not usually sold because it would end up being
consumed as liquor, thereby bypassing the liquor control, and tax laws.
It's is "denatured" by adding methyl (wood) alcohol to it.  Since methyl
alcohol is poisonous (it can make you blind) it discourages oral
consumption, and makes it easier to purchase ethyl alcohol without a license.
>
>What does this have to do with pianos?  The keytops are usually made of an
acrylic.  When the keytops are dissolved in acetone the acrylic
de-polymerizes, but does not change into a different polymer.  When the
keytop mixture is applied to a felt hammer the acetone flashes off and
leaves behind the acrylic in the hammer which tends to "glue" the fibers of
the felt together making the hammer harder.
>
>Some technicians use a mixture of denatured alcohol and water to soften
hammers.  How does this work?  The lanolin in the wool felt is a lipid and
such is hydrophobic, that is water beads up on it.  In order to get very
polar water past the non-polar fat (lanolin) one needs a wetting agent.  In
this case the alcohol keeps the water from beading up on the wool, allowing
the water to drive deep into the felt where it causes the wool to swell,
and soften.  Soaps are wetting agents that allow water (a strongly polar
molecule) to dissolve fats (highly non-polar substances).  In the same way
the alcohol acts like a wetting agent for the water to penetrate the wool.
>
>The reason that plastic toys, car interiors, and such "dry out" and crack
with age has nothing to do with taking years for the plastic to "cure".
Plasticizers are added to polymers to make them softer and more flexible.
Over time these plasticizers vaporize out of the plastic leaving the hard
polymer behind.  Eventually it cracks.  That oily film on the inside of
your car windows on a warm day is the plasicizer coming out of the soft
plastic parts of your car's interior like the dashboard.  That's why old
cars have cracked dashboards.  I strongly doubt that the acrylic used in
keytops has any plasticizers added.
>
>Sorry for the science lecture.  Hope it was useful.
>
>Jory Olson
>
>
>
>
Roger Jolly
Balwin Yamaha Piano Centres.
Saskatoon/Regina.
Canada.