[CAUT] McLube thoughts

[Fred Sturm]

On 8/3/06 4:43 PM, "Don Mannino" <DMannino at kawaius.com> wrote:

> My experience has been that heavy, repeated application to key pins can cause
> the felt to become compacted and hard.  This is not from a single application,
> mind you - the only time I have personally seen this problem was in a piano
> that was getting a treatment each month by a tuner who was trying to prevent
> bushing wear in a crazily heavily used instrument.  After about a year, the
> bushings seemed worn out because the keys had become loose and noisy.  On
> close inspection, though, the bushings were not worn, but were compacted and
> waxy feeling.  After a quick steam application and inserting sized cauls, the
> keys were good as new.  So the McLube seems to have prevented wear, but the
> bushing was so hard and compressed that it seemed worn out anyway.

Hi Don,
    I¹m thinking this was application to the key bushings, not the pins,
from what you are describing. And, yes, in that case the residue would build
up in felt and become hard. I can¹t imagine it building up on key pins if
you apply it with a cloth. The solvent on the cloth will tend to pick up any
remaining residue, and the amount of ³hard white material² left will be
pretty minimal. I don¹t think it would transfer much to the cloth bushings.
Maybe a bit to the surface, but it wouldn¹t penetrate and turn the cloth
hard. And if application of McLube only follows polishing with Flitz, there
will never be much build up.
    For application to bushings with keys and action in place, I think
Protek CLP or ProLube would be much better choices. I¹m not sure that they
might not become gummy over a long period of years, but over a few years
that doesn¹t seem to be a problem. They seem to cure most squeaky bushings
fairly permanently, unless the felt is worn away to the glue.
    I do think McLube is essentially the same material that Steinway uses to
impregnate flange bushings. For that purpose, stiffness can be a virtue. Not
for key bushings, though.
    I¹m willing to accept your description of the residue as somewhat waxy,
but not nearly as soft as cold paraffin. A fingernail won¹t dent it readily.
Regards,
Fred Sturm
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