Polyurethane Finishes on pianos

[Farrell]

Well, I think a big question here is just what is brand "x" clear finish. I
think we need to know a little more about it to even make any guesses. Do
you get any ginsu knives and maybe a juicer with it? (just kidding)

As to refinishing a piano with an existing polyurethane finish - if the
polyurethane finish has good adhesion to the wood beneath, it makes an
excellent base for virtually any coating. You can even use the real hard
two-part polyurethane finishes, or water base laquer, or regular laquer  or
virtually anything. (I wonder if the solvents in nitrocellulous laquer might
melt the poly a bit - and cause a problem???? Probably not - but I don't
know.) But the key is the condition of the poly finish. If it is cracked -
look out! At a minimum you will need to do some major epoxy repairs for
every crack (see West System technical papers for poly repair procedures at:
www.westsystem.com). If it has the spider-web type cracks - lots of little
ones - forget it. Your new finish will be cracked just like the poly in no
time.

When thinking about a poly finish, think about a fiberglass boat, or a
Corvette (at least the old ones). Except for the glass matting below the
surface, the polyurethane at the surface is very similar - whatever you can
do to your 'Vette, you can do to your piano - not that you would necessarily
want to. I've seen some wild paint jobs on 'Vettes that might raise an
eyebrow or two if applied to a piano.

Regarding whether applying a polyester finish might be as easy or easier
than laquer - when a fiberglass boat or a Corvette turn a new color, it
ain't from an application of polyester - it will be spray painted with some
type of paint - and for a good reason!

Thar's my two cents worth.

Terry Farrell

----- Original Message -----
From: "Robert Goodale" <rrg@unlv.edu>
To: <pianotech@ptg.org>
Sent: Monday, December 10, 2001 4:10 PM
Subject: Polyurethane Finishes on pianos


> Just kind of wondering-
>
> Has anyone ever experimented with refinishing pianos with a polyurethane
> type finish?  I was browsing the finishing department at my local Home
> Depot when a display sample caught my eye.  You know, those little
> samples of wood that have had brand "x" applied to show you what the
> product looks like.  I have to admit some of them looked pretty darn
> good.  One of them was a "crystal clear" variety which was very smooth
> and uniform and was quite heavy and durable.  It looked virtually
> identical to a coat of  clear Polyester.  It is also available in a
> satin version.  I would guess that a coloring powder could be added for
> an ebony finish.  The container also says that it can be applied by a
> sprayer.  All of this would SUGGEST that you you could apply a
> "simulated polyester finish", (for lack of a better term), for a more
> modern look on an old piano.  The questions are: 1.  Will it last 50
> years?  2.  Is it practical to refinish a piano this way or would you
> spend three months of your life sanding, rubbing, and polishing?
>
> Rob Goodale, RPT
> Las Vegas, NV
>