Polyurethane Finishes on pianos

[Isaac OLEG SIMANOT]

Hello, John,

Thanks for your lights,

French polishing = Vernis au tampon
the Rubber = le tampon
bodying =  remplir (with ponce powder and alcohol an a very few varnish)
or may be "faire monter le vernis"
oil = "graisser le tampon"
the oil used for French polishing is often "oeillette oil", I thought
linseed was too heavy for French polishing.

When I talk about cellulosic it is just a variety of alcohol diluted lacquer
suitable for French polishing, (we use it as the traditional French polish,
with 95° alcohol) it is easier to use, is very bright, and a little thin.
You don't have to wait so much between the passes, and possibly it does not
harden so much.

When I talk about oil base varnish, this is because I was told than most of
the German pianos where finished with this kind of finish (something like
the "flatting" varnish if that name is same in English). Am I wrong ? I
don't know, but I thought that French polishing was mostly on French pianos
(and English ones too, but the way it is conducted possibly be different in
England because the preparation of the support with hot rabbit glue vs.
ponce powder in France.


> French polish, so called because the technique was apparently first
> used in France as "Vernis Jacques", is a solution of lac in spirit.
> It contains no oil.  There are many different qualities of lac
> depending on the amount of wax removed, the decoloring etc.  What is
> sold with the name "French Polish" is generally a less expensive
> variety containing a certain amount of the natural wax from the
> bodies of the lac beetle that are used to make the shellac.
>
> >I had sometime good results on a refinishing with a cellulosic
> French polish that could be use on an existent finish (oil based) assuming
the
> precedent was decontaminated, buffed and clean.
>
> If all you want is a shiny finish, anything goes.  If you want the
> original clear figure of the wood to shine through and give depth to
> the finish, there is no alternative to remove the old finish and
> start from the bare wood.

Yes the wood is always a little masked with the new coat, I've been show a
method to renew an old varnish with alcohol and a very few new varnish (lac)
. It is suitable for soundboards too, and that is what I used with this
cellulosic french poslish. Because it is drying fast I can work on the old
finish without softening it too much.

When finish, we use a product called NIKKO to dry the surface and have all
the remaining oil off (it clears the surface too). The same product is used
to renew old finishing, it have some acid and Tripoli powder in it, soften
the surface of old varnish so you can have it shiny again. Do you use this
product too ?

One of the reasons I hate polyester (and
> there are many!) is that it gives no depth and richness.  It is just
> a thick coat of bluish plastic and in my opinion the most disgusting
> finish.  As to cellulose, whatever it's quality, I would never use it
> again.  Even the acid-catalysed varieties never go hard and a real
> "glass finish" in impossible.
>
> >
> >But I don't know how to have black French polishing. What kind of tint do
> >you use ?
>
> You can buy ready-made black polish but this is based on "button
> polish" which is a quality I do not normally use.

Is it what we call Copal or "vernis a mecher" used with a piece of cotton ?
You may pass only once with this quality,and without any oil ?

Instead I use a
> decoloured clear polish or "special pale" to which I add "spirit
> black".  The color of this black is a very dark mauvish tint which
> gives the effect of a very rich black.  This is the dye that has
> always been used for black finishes on pianos.

I was guessing that the old pianos black finish was first the wood tinted
black with a natural  "bois de campeche" tint (and dichromate of potassium
as a "mordant" agent)
this is a little reddish violet black, is it what you call spirit black ?

or is there any other dye (aniline, or alcohol tint, or fushin) you know ?
Is the dye mixed in a large quantity, or a little is enough ?

BTW, do you know a kind of "easy" French polishing called 'Furniclass' ?
and what is the name of the finish where the lac is mixed with wax (we call
that "Mattine" finish)

Last but not last, have you a good source of bushing actually , Jahn have
only 1.3 and 1.6 mm quality, Renner only 1.2, Kluge actually uses only 1.2
mm from Renner and I don't have any good source for quality pure wool
bushing felts. Is Fletcher Ok (I guess ....)

Best Regards.

Isaac OLEG