my own Soundboard

[Ron Nossaman]

Hi Greg,

There are a lot of different approaches and tooling preferences. I'll give
you mine. 

I haven't assembled my own panels because I have neither the shop space for
thicknessing machinery, which in my case would probably have to be a stroke
sander, nor the volume requirement to change that. While I have sent a few
panels back to suppliers when they didn't remotely resemble what I had
requested, it has for the most part been an acceptable means of getting a
panel. Would I prefer to build my own? Sure.

Crowning ribs is a matter of deciding what you want in a crown radius (or
crown radii) and coming up with a jig and tooling to produce it (them) in
the ribs. There are as many ways to do this as there are soundboard
installers. Your first idea will probably work. Your second idea will
probably work better.

For gluing ribs to panels, I like pneumatic clamps similar to those shown
in Claire Davies' PTJ article. I like pneumatic because I can feather the
ribs quickly and easily with a jig and router setup before gluing them on
and still get uniform clamp pressure on the joint without having to mess
with spacers and cauls. I use five clamps. Mine are made of maple, to keep
caul flex to a minimum, with a different radius curve cut into each. The
radii get tighter toward the treble. I don't mount them on a frame of any
sort, and just move them from rib to rib as I work. No, it's not necessary
to keep everything "level" as you go. The board doesn't care and will
accommodate when it's glued in. With the panel dried to 6%MC, using
Titebond, by the time I get five ribs glued on, the first clamp can be
taken off and moved to the next rib. I'll usually give them a little longer
though, for insurance. I've been running the air pressure to the clamps at
40 PSI with no problems. 


For gluing the finished board in, I like regular old F clamps and wooden
spacer blocks. The clamps are available commercially without having to make
them, and they are a general use clamp, rather than specifically dedicated,
which come in handy for plenty of other uses around the shop. I have a
couple of dozen 4.5"x24" I got from New Mexico Woodworking (I think),
because I couldn't find available Besseys in that size at the time, and a
dozen 2.5"x18" Besseys for the belly rail and less ambitious general
purpose around the shop clamping. Jorgenson, Record, and Stabil make pretty
first rate F clamps too. For clamping the panel to a cutoff bar, I use go
bars made from old maple flooring. Very low tech, and very effective. I
make a perimeter caul out of cheap 3/4" plywood, the width of the inner
rim, to help distribute the clamp load evenly on the panel and keep the
spacer blocks from denting the surface. 

Dry fit the assembly in the rim, trimming ribs as necessary to make sure
everything fits to your satisfaction (including a dry run with clamps)
before gluing. Here's where you locate and install the bridge too. Clamping
the board in, or temporarily screwing it down, you either locate the bridge
from a pattern made before teardown (if you want the bridge back where it
originally was), or you can lay the bridge on the soundboard, drop in the
plate, and locate both where you want them at the same time. Hint: you
can't slide the bridge in under the plate once it is down, so don't forget
to lay it on the board first. Another hint: you will probably eventually
verify this for yourself. Mark the bridge position on the board, pull the
plate, remove the board, glue and screw the bridge to the board, and you're
ready to install it. 

Do a full dry run installation or two with a helper so everyone knows what
to do when and work out the choreography so you're not gluing and clamping
one another instead of the board. With your board at whatever your working
%MC was when you glued on the ribs, quickly apply plenty of glue to the
inner rim and belly rail, lay in the board, lay on the perimeter caul(s),
set in spacer blocks and clamp as you go. I like to start clamping at the
right front and left rear, because these areas will have to be pushed down
farthest to meet the rim and this will tend to press the rest of the board
perimeter into wet glue as soon as possible. 

Don't try to crush the piano with the clamps, and don't forget to mop up
the squeeze out while it's still wet. 

Oh yes. Now that you have the board glued in - it's easier to finish the
bottom before you do that than after it's installed. Just keep the finish
off of the gluing surface, as you already know.

That's probably not everything, but it's a start. I hope it's of some help.

Ron N