Soundboard varnishes

[Farrell]

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
>  
>