Soundboard shims via Spurlok method

[Robert Goodale]

Hold the phone, don't do anything yet!!

The spurlock system is an AWESOME way to repair sound boards.  I have used
it to repair literally hundreds of cracks and would never use any other
system again.  When the repair is done it is seamless and virtually
invisible.  If you can't get it to work then you simply aren't doing it
correctly.  It takes practice and patients but when you get it figured out
you will never go back.  Your customers will nick name you "piano god".

First things first.  I found that right out of the box the slots in the jig
are a bit to narrow.  (Make certain you are using aluminum, NOT steel!)  If
it is tight ream the slots using a hacksaw blade held slightly sideways.
Then clean it up a bit with some sandpaper.  Do not over do it or the jig
will ride sloppy on the rails.

Next remove two of the plastic screws on one side.  The rail will elevate
the jig only on one side so the other side just needs to be raised level
it.  I found on mine that screwing them in all the way provides all the
leveling I need.

You are correct, the crown of the board does not allow the rail to rest
flat.  Mount the rail using double sided foam tape.  On the outside ends
use two pieces stuck together, (three if needed), to make up the distance
of the crown.  Problem solved.  The rail may wobble slightly from side to
side but the rail is only to steer the jig straight, not to support it.
That's where you come in.  You will need to guide the tool along while
applying downward pressure, not unlike running any ordinary router.
Assuming that it is level, (via the bottom plastic screws), it should glide
along with no problems.  Just keep a tight grip.

One of the most critical points which I suspect may be your biggest problem
is that the rotation of the router must be so that the cutting edges move
toward the rail.  This means that there is only on direction that the
router may be moved.  You need to determine which end of the rail is where
you will start at before you begin.  If you move the router backwards it
will chatter and bounce around, completely ruining your slot in the
process.

If you do this correctly the shim should fit in the slot like a glove.  Use
cold hide glue only.  Yellow glue will not only be more visible but it also
doesn't have the "glass hard" properties that hide glue has which works
better in preserving the acoustic properties of the board.  Allow the glue
to completely dry before trimming since the glue will cause the wood to
swell slightly.  Once it is dry use a block plane to shave the shim down
flush with the board.  Carefully use a sharp chisel to clean up the
underside of the board if necessary.  When using a chisel always remember
the rule:  Make it sharp, go with the grain!

If the board has a yellow/orange color, carefully apply thinned coats of
orange shellac until the color of the shim matches the surrounding wood.
Once you lacquer the entire board, apply a new decal, and restring the
piano, the repair will be virtually invisible.  Structurally it will also
be the best repair you can possibly make.  You will NEVER use epoxy again!

Rob Goodale, RPT
Las Vegas, NV

Greg Newell wrote:

> I've got trouble. I just started using the sound board router system
> the venerable Mr. Bill Spurlock sells. I don't like it! Maybe it's just
> me but I can't get a handle on how to affix a rail to the crowned sound
> board. I would be easier if the board was flat bu then I'd be replacing
> it not shimming it. I've always been taught that a glue joint is only as
> good as the mating surfaces. I have several small gaps in various places
> and I've gone as wide as I dare with the shims that I have. Kind of like
> the wobbly chair syndrome. I've never had a router bit cut so poorly,
> chattering and pulling like it did.
> I am gluing the shim in now with as much of the gaps minimized as
> possible but I'm finicky. I'd rather not see any at all. I think I'll
> switch gears here and try the epoxy method. Would any of you be so kind
> as to detail this method to me along with the product you use and your
> results with it. Before the forum police come to get me, I know this has
> been posted before. Nevertheless I'd appreciate a complete approach if
> any of you are so inclined.