Wood

[Delwin D Fandrich]

----- Original Message -----
From: "Richard Brekne" <Richard.Brekne@grieg.uib.no>
To: "Pianotech" <pianotech@ptg.org>
Sent: February 15, 2003 4:17 PM
Subject: Re: Wood


>
>
> > As we continue to refine our epoxy-saturation soundboard coating
technique
> > the results are promising enough that I would have to say, yes, epoxy
coated
> > soundboards have at least some potential down the road.
>
> This is just a coating... no way of ( or pehaps reason either ) to
penetrate the
> wood fibers ? Doesnt epoxy get kind of brittle ... as in it doenst like
being
> bent ... I'm sure you have thought of these kinds of things... just
interested
> in what you came up with.

It does penetrate, but only superficially--that is, it penetrates in the way
that any other equally viscous liquid would penetrate, not as a water vapor
penetrates. It gets into the outer surface only--fractions of a mm. On
endgrain it goes some further because of the porosity of the material. A
true 'coating' epoxy penetrates some further than do the more common
'structural' epoxies because of its very long pot life, not because of
anything magical in its formulation.

Epoxy, especially in thin section, is not particularly brittle. Pour a thin
layer of a good coating epoxy out on some waxed paper, let it cure and flex
it. In thicknesses common to coating epoxies and within the range of motion
found in the average piano soundboard, its flexible enough. As a class,
polyesters are considerably more brittle than epoxies and even these work
reasonably well as finishes, albeit ugly ones, over wood.


>
> Well... it way really key frames I was origionally irritated with. I've
often
> wondered why they dont use ply for this... Or perhaps MP3... that highly
> compressed stuff they use for speakers often these days.

MP3?

Del