Soundboards ... Seriously

[gordon stelter]

YES!!!!! Use "Duravar" from M.L. Campbell. This is a
bowling alley, 2-part varnish, VERY hard!
     I believe that I have successfully recrowned a
board by 1) Screwing a 2x10" plank to the back of a
piano, in a  climate controlled finishing room with
the humidity as low as possible, with a tracing on the
plank of the bridge curve ( mylar pattern ) 2) Drilled
holes in the plank to correspond with the intersection
of rib to bridge line on other side of soundboard.
3)Throughly screwed down soundboard to rim from front
with retaining strips, etc. 4)Tapped threaded inserts
into plank holes ( cheap, from hardware store ) 
5) Made saddle blocks to ride, protect ribs . 
6)Screwed 10" long, 3/8"diameter bolts through plank
to press on spoundboard from back,on saddle blocks,
along bridge line, until I just started to hear
splintering. 6) Mixed up some Duravar, and thinned 60%
with lacquer thinner ( guesstimate ). 7) Sprayed on
soundboard, front and back, to soak into board. 
     My theory was that, by adding some material to
the board, I could compensate for compressed spruce
fibers, and regain crown. 
     I went back with several coats, thinned
progressively less.  8) Let it all cure for a couple
of months while doing something else. This stuff
permits loads of formaldehyde while curing, so you
want a separate shed to do it in!
     9) Take off brace, and string.
     I just did this to a non-descript 1922 Krakauer
upright, and it REALLY sounds better than the Steinway
uprights, same size, at University!!!
    I believe this is due to regained crown, as well
as the severe hardness of this stuff passing string
vibrations across the face of the board like
lightening! I also thinly coated the bridges with
West's epoxy, wafted over by heat gun ( before doing
board ).
    This piano is in a church with very unstable
climate. It sounds amazingly nice, and they love it! I
also intend to put a thin polyethylene sheet across
the back, covered with speaker cloth, and foam
weatherstrip under lid edges, etc., to keep air from
circulating within.
TIP: To avoid buying $500  explosion proof exhaust fan
for your finishing shop (that sucks in bugs and dirt
from everywhere else) go get alittle poratable
building, 10'x 12' or larger, and build a wind tunnel
on the back of it, into which 3 cheap, window "box
fans" can be stuck in a row, to push air INTO the
shop, through furnace filters. On the other side, have
screen window.
     This is how I made mine, with  Sears dehumidifier
draining outside, and all very shutterable for
humidity control.
    Electrical conduit on ceiling with loops of cord
connect to screw eyes in piano panel pieces ( almost
every panel has a place to screw them in!)can hang up
all panels like this, spray both sides, let hang to
cure. TOTALLY DUSTPROOF!!!!!( Almost fun! )
    Gordon Stelter


--- Ron Nossaman <RNossaman@cox.net> wrote:
> 
> >Has anyone you know of experimented with a
> different, impervious material 
> >for soundboards or a sealing technique that would
> take a lot of the 
> >humidity factor out of pitch stability?
> >
> >Alan Barnard
> 
> 
> For one:
>
http://www.speech.kth.se/music/5_lectures/conklin/newmaterials.html
> 
> But then there's the rust...
> 
> Just putting ribs on both top and bottom of a
> conventional board, solid or 
> laminated, should make a substantial difference.
> 
> Ron N
> 


__________________________________________________
Do You Yahoo!?
Yahoo! Finance - Get real-time stock quotes
http://finance.yahoo.com