System Three Varnish

[Delwin D Fandrich]

----- Original Message -----
From: "David Love" <davidlovepianos@earthlink.net>
To: "Pianotech" <pianotech@ptg.org>
Sent: February 28, 2003 5:50 PM
Subject: Re: System Three Varnish


>
> I'm not sure why the flexibility of the varnish would matter.  Either the
> board is stiff or it isn't.  In the case of an epoxied board, the epoxy
> provides the stiffness and the varnish topcoat is not required to
> contribute additional stiffness.  Nor would it make the epoxy any less
> stiff by virtue of its flexibility, if it is, in fact, flexible.  I have
> used varnishes for years on soundboards, usually over a shellac undercoat
> without detriment.  In this case, since I am stiffening the board with
> epoxy and System Three makes a varnish that supposedly does not have any
> compatibility with their epoxy.  I was more wondering about the cosmetic
> quality.


David,

As I said earlier, I've not used System Three varnish. But the compatibility
issue may be a valid one. I've had one combination of epoxy/varnish give me
problems. The varnish never did thoroughly dry and had to be stripped off
and replaced. It also softened the surface of the epoxy. It had to be
scraped down to hard, clean epoxy. I took it back to just the surface of the
wood. All in all a real mess. I then recoated and went on. This was some
years back and the epoxy was an off-brand purchased from a (then) local
marine supply store. The varnish was purchased at a (then) local paint
store. I don't remember the brand but it was not one of the major marine
varnishes. I've subsequently been told that these problems are rare but they
still can occur. I don't know why they occur or what there is in either
product that might create the potential problem. The chemists out there are
welcome to have a go at it.

My experience with soundboard coatings has convinced me that the physical
characteristics of the finish material are incidental to the soundboard's
performance until either their mass or stiffness becomes a significant
percentage of the whole. In the case of the epoxy coating the stiffness of
the soundboard system is increased (significantly) and mass is increased
(slightly). I can't see any common coating material on its own doing either.

Del