System Three Varnish

[Delwin D Fandrich]

----- Original Message -----
From: "gordon stelter" <lclgcnp@yahoo.com>
To: <davidlovepianos@earthlink.net>; "Pianotech" <pianotech@ptg.org>
Sent: March 01, 2003 8:11 PM
Subject: Re: System Three Varnish


>      HOWEVER, I would still prefer a finish which
> will, in my opinion, carry the vibrations away from
> the bridge rapidly while absorbing them least, to
> excite every portion of the board.

Well, ok. But that's not how soundboards work.


>
> And one which
> really seals the board against humidity, as much as
> possible.

Have you tested your finish of choice as a vapor barrier? Of those we tested
way back when only epoxy showed any real promise as a viable vapor barrier
and then only when used in obscene thicknesses: three to four plus coats
totalling close to 1 mm or better in film thickness. Nothing else performed
any better than the material the company was already using (some kind of
conversion varnish).



> But, if you are trying to create rigidity,
> would you not want the stiffest (when cured) and least
> viscous epoxy you can find, as long as it is not thin
> due to solvent thinners? And isn't Epotek 301 the best
> by this criteria? Wouldn't you want it to permeate the
> board as much as possible? I'm sorry to say that I
> have not read your articles yet.But I will, ASAP.

I considered Epotek but was unable to get much information from the company
about their product. Since it is apparently formulated primarily as an
optical grade material I had some reservations about its use in my process.
I was unable to get samples to test at the time. No, I didn't want it to
permeate the board as much as possible. I wanted it to remain a coating in
matrix with the surface. And this is what the epoxies listed in the article
all do.

I spent several hours today listening to the most recent piano we've done
with this process--a Bush & Lane 5' 9" grand--and am quite happy with the
results. The sound of this piano now compares favorably with any new grand
piano of similar size--indeed, I'd happily compare it to a new 5' 10 1/2"
grand of well-known manufacture. Yes, the piano has been rescaled and the
bass bridge has been modified to shorten the speaking length and increase
the backscale length, but the board is original and the design is otherwise
fairly conventional for a grand from the early 20th century. My remaining
question is longevity. And I suspect that is going to be tied to the UV
blocking characteristic of the finish material used to coat the epoxy. On
this board we used a good quality marine varnish. And we did rub it out
after it had dried for about two weeks.

Del