Soundboard varnishes

[David Love]

Terry:

At 3mm thickness, of course, you would expect to have an effect on tone. 
But what about 1 mm?  Or better, at what percent thickness would you expect
the varnish to have an effect on tone and does level of hardness have any
bearing?  I guess I'm calling for speculation.  

David Love
davidlovepianos@earthlink.net


> [Original Message]
> From: Farrell <mfarrel2@tampabay.rr.com>
> To: Pianotech <pianotech@ptg.org>
> Date: 3/19/2003 4:21:00 AM
> Subject: Re: Soundboard varnishes
>
> I have one bit of knowledge that would not be speculation. Varnish should
have no effect on epoxy underneath it - except of course for the visual
effects. I trust your inquiry regarded the integrity of the epoxy. And I'll
go one step further and say that varnish will adhere very well to a
properly prepared epoxy surface (sanded, etc.).
>
> Your last statement appears that you are not adverse to
speculation.........so here goes. My understanding regarding finish types
and thickness influencing sound output is this: It likely does not matter a
whole lot what you use, just keep it to a minimum. Whatever you use, the
thinner it is, the more your soundboard will remain like a spruce
soundboard. Put a 3 mm thick coat of polyurethane on the board and suddenly
you have a board whose thickness 25% plastic - you don't have just a spruce
soundboard anymore.
>
> One thing that I like about varnish is that proper application is very
thin. Twelve coats can give you a dynamite finish with lots of depth. But
it can look very nice with three coats.
>
> Terry Farrell
>   
> ----- Original Message ----- 
> From: "David Love" <davidlovepianos@earthlink.net>
> To: "Pianotech" <pianotech@ptg.org>
> Sent: Wednesday, March 19, 2003 2:49 AM
> Subject: Soundboard varnishes
>
>
> > 
> > Awhile back we were having a discussion on the merits of various kinds
of varnishes.  I continue to explore the effects of varnish on soundboards
(if any) and have a few questions.  
> >  
> > First, what differentiates the type of varnish used on violins and
cellos from the spar varnish often used on pianos.  I notice that the
varnish on violins is quite hard, even brittle, whereas spar varnishes are
typically a bit rubbery (have I answered my own question?).  What is the
composition of violin varnishes, typically--I know, for Stradivarius it was
a secret.  How might this difference effect tone on a soundboard.   And, is
there a reason to select a very hard, even brittle finish? 
> >  
> > Second, are there potential ill effects from putting too heavy a coat
of varnish  on a board.  Can too heavy a coat of rubbery spar varnish
actually impede sound transmission through the board, and how thick would
it have to be to create a problem.  
> >  
> > Third, can varnish effect epoxy underneath it?
> >  
> > I would be more interested in experiences and side by side comparisons
than speculations, but please feel free to comment either way.
> >  
> > Thanks,
> >  
> > David Love
> > davidlovepianos@earthlink.net
> >  
> > 
> _______________________________________________
> pianotech list info: https://www.moypiano.com/resources/#archives