Varnish on Soundboards

[bases-loaded@juno.com]

Hi David -

As far as I'm concerned, all of your questions here are good ones, and I
have no idea at all what too thick a finish would do to the tone.  Never
went there.  Clearly, some common sense when applying finish on ANYTHING
is a major plus, and seems to have been absent in the instance you
relate.  A finish that is "very heavy" and "still quite rubbery and
flexes to the touch" was obviously improperly applied, at the very least.
 Sounds like the undercoats never got a chance to cure before top coats
were 'poured' on.  My personal preference is to apply a couple thin coats
of shellac, sometimes tinted with dyes for warmth or color shifting, and
then 2-3 top coats of water-based lacquer, the last coat being
semi-gloss.  I seldom rub it out.  Shellac is famous for its ability to
act as a vapor barrier, and is very flattering to wood cosmetically, as
well.  I don't know why you would need more 2-3 coats on top of that. 
Rightly or wrongly, I guess I don't picture the finish playing a
significant role in the sound production, except negatively if umpteen
coats are dumped on without curing?.    Let us know if you get the
opportunity to take off this gooey mess and listen to any possible
changes in tone.

Mark  

On Thu, 20 Mar 2003 06:52:26 -0800 "David Love"
<davidlovepianos@earthlink.net> writes:
> Mark:
> 
> I recall the message(s) from Del and have read is recent posts and 
> articles
> on epoxy on soundboards.  One of the questions I have is how thick 
> is too
> thick.  Joe G. addressed this somewhat in his post.  It suggests 
> that a
> finish can be too thick and that a rubbery type finish applied too 
> thick
> can reduce the function of the board.  The consensus on all post is 
> that
> the ultimate finish should be very thin and should dry relatively 
> hard. 
> I've encountered a piano recently that has a very heavy coat of 
> varnish on
> it, fairly recently applied (1 year or so ago).  The finish is still 
> quite
> rubbery and flexes slightly to the touch.  I don't know if it is 
> over epoxy
> or not.  The sound of the board is strange, weak with poor sustain 
> though
> the board is showing some crown and positive but not excessive 
> bearing.  I
> did not hear the piano prior to the restringing so I don't have a 
> way to
> compare but I am suspicious about the finish.  Part of my question 
> is
> wondering if this piano might not have a problem due to the 
> thickness and
> flexibility of the finish.   Though Del's research might have 
> suggested
> that the types of finishes he applied within a relatively narrow 
> range of
> thicknesses had no effect, that may not have been conclusive about 
> how
> finishes improperly applied might not have a deleterious effect on
> soundboard performance.   He has talked about the importance of 
> stiffness
> in a board, but if you get that stiffness by adding mass there you 
> could
> create a problem.  If Del is reading this, perhaps he can comment.  
> I am
> tempted with this particular piano to suggest stripping it down and
> scraping the finish off and replacing it with a thinner harder 
> finish, but
> since I can't be sure of the results I can't do that in good 
> conscience.    
> 
> My query with respect to violins was only because I know that violin 
> makers
> seem interested in finishes with respect to how they effect sound.  
> I was
> interested to hear from  Gerald Posey on the subject.  It sounds 
> like a PhD
> thesis, however, and I can't go there right now.  Many people, I 
> notice,
> are using lacquer on soundboards these days.  Lacquer dries quite 
> hard,
> even brittle.  Some varnishes, as Mr Posey suggests, remain quite 
> flexible,
> others get much harder.  Old finishes on soundboards are clearly 
> quite hard
> as evidenced by how they respond when you scrape them off.   In my 
> own
> approach to soundboard finishing I have used varnish and never 
> really
> thought that much about the type of varnish, how hard it gets, how 
> thick is
> too thick or how flexible is too flexible.  It may be that 
> flexibility is
> not an issue until it gets too thick.  Because of my recent 
> experience, I
> thought that perhaps I should think about it more to avoid a 
> potential
> problem.   
> 
> David Love
> davidlovepianos@earthlink.net
> 
> 
> > [Original Message]
> > From: <bases-loaded@juno.com>
> > To: <pianotech@ptg.org>
> > Date: 3/19/2003 1:17:47 PM
> > Subject: Re: Varnish on Soundboards
> >
> > David -
> >
> > Far be it from me to speak for Del, but I saved a message to 
> Pianotech
> > from him some time back that told of the experiments he conducted 
> with
> > different finishes on soundboards of similar new Baldwins back in 
> his
> > Baldwin days, and the conclusion was that there was no 
> appreciable
> > difference in tone quality, given reasonable and similar 
> thicknesses in
> > various finishes (at least that's what I got out of it).  My 
> personal
> > speculation is that "needing the perfect elixir for the 
> soundboard
> > finish"  is just another of those voodoo tales that permeate the
> > instrument trades.  I have been using water-based lacquer for 
> soundboards
> > for the past 8-10 years with no discernible "loss in tonal 
> quality".  
> > That being said, personal testimonies seem a tad worthless, eh?   
> Unless
> > one had multiple instruments of known similar quality, and the 
> ONLY thing
> > different about each one was the soundboard finish, how would one
> > quantify results?  THAT'S what struck me about Del's post.... 
> seemed more
> > 'telling' to me than a hundred personal testimonials....
> >
> > Mark Potter
> > bases-loaded@juno.com
> > _______________________________________________
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> 
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