lubricant

[Paul S. Larudee]

JIMRPT@AOL.COM wrote:
> 
> "Verdigris" is  a green waxy build up as evidenced on action
> centers/pins/flanges bushing cloth. The buildup of this substance eventually
> causes problems in repetition/regulation/playing. The definiton of "Verdigris
> is : "A green patina or crust of copper sulfate or copper chloride" In pianos
> this sulfate/chloride is normally accompanied by a waxy substance.

"Verdigris" is a Languedoc word (Provencal, spoken in southern France,
is a modern descendant of Languedoc) which best translates as "grayish
green."  It is rust - specifically corroded copper, which is one of the
metals in the alloy used for center pins - and can be caused by
corrosive agents like sulfur or chlorine.  Since rust is porous, it can
absorb other substances like the lubricants used to treat (or mistreat)
action centers, or whatever chemicals may remain or have been
deliberately introduced into the bushing cloth.  A chemical reaction can
sometimes take place between these substances and the corrosive agents,
the result of which is usually a thickening of the substances.

Polymers are highly stable long-chain molecules which for all practical
purposes will react with almost no chemical, and certainly not with
anything encountered in action centers or anywhere else in the piano. 
Their only effect is to reduce the friction of whatever they coat. 
Protek CLP therefore makes the corrosion and whatever other gunk (an
esoteric technical term) may be there slipperier than it would otherwise
have been.  Furthermore, the slipperiness is long term, because of the
stability of the polymers.

Probably more than anyone wanted to know.

Paul S. Larudee, RPT
Richmond, CA