Hello all,
As a former professional furniture maker, whose favorite wood has
always been walnut:
1/16 outer plys??? Not likely. Typical Walnut ply had face veneers of
only 1/42 inch (or less!) back in the late 80's... I'd imagine it's
thinner now. (I work almost exclusively with solid walnut lumber now;
see the next paragraph for some reasons.)
Be VERY careful when specifying walnut ply. There has been a tendency
for mfrs to use a paper thin walut (forcolor/grain) with an obeche or
similar wood "backing it up" to make the outer veneer APPEAR thicker.
This ply is VERY subject to scratching (phono plug tips anyone?);
which will leave a lighter (and permanent) mark. You cannot "sand
this out" as you WILL go through the outer veneer!
Using a lumber core type plywood will generally result in thicker
outer veneers and a stiffer panel in the sizes and shapes you'll need
for synth cabs. Keep in mind that in a board, all the fibers run one
way, increasing strength; while a conventional ply will have over 1/2
the fibers running the "wrong" way for the stiffness you need from
the top and bottom panel of a wide synth cabinet. Specifying 8x4 (as
opposed to 4x8) will help if you must use conventioanl crosslaid ply,
as this spec will make the outer veneers run in the "short"
direction; which will result in more inner layers running "with"
the "outer" grain...
Also, the comment about LENGTH moving 1/4 inch was WAY off. Wood
moves a great deal in WIDTH, and nearly not at all in LENGTH. It also
moves in thickness. Width and thickness movement will be related to
the woods' tangential and radial movement. Which one is related to
width and which relates to thickness will depend upon how the board
was sawn from the tree. (i.e., quarter sawn will have radial across
the width, and tangential in thickness.) Some woods have a LARGE
variation in tangential versus radial movement; American black walnut
(Juglans nigra) does not. Tangential movement is nearly always
greater than radial; often up to two times as much. This matters
because it will affect the size of the rabbets you are mounting your
panels to, which will affect the overall height provided for the
synth panels. Carefully choosing boards can minimise or constrain the
movement AWAY from areas where you need tight tolerances.
You can look up the shrinkage/movemnt percentages for many common
woods at the Forest Prodcuts Laboratory site. They are located in
Madison, WI. and publish everything technical you need to know about
using wood.
California walnut (Claro) and Bastogne, which is actually
transplanted English; usually have MUCH more figure (tiger, or
fiddleback) than the typical Eastern Black sold more commercially.
Most gunstock walnut comes from Northern California, for example. One
reason to laminate your own ply is to get such a figure; along with
the desirable thicker outer veneers. Remember the old ply Aries synth
cabinets? Yech!
Anyway, don't fret about using GOOD QUALITY walnut in board form to
make synth cabinets. Walnut has been used in furniture with tightly
fitting doors and drawers for centuries. And also by a guy named
Moog<G>. I stress the good quality part because commercial walnut
trees are getting smaller every year, and many/most boards now
contain the sapwood which is white. This has led to lumber mills
staining the sapwood to mute it and blend it with the harder and more
durable (and more stable dimensionally) heartwood.
The biggest variable is the moisture content of the wood when it is
mfg'd and shipped. Jerry Metz repeatedly tells Furniture mfrs to
meter ALL their wood as it comes in and to specify 6-1/2% moisture
content.(And he's speaking to factories which control their humidity
and temperature 24/7.)
I've shipped furniture all over the world, and you have to take into
account the final destination when fitting something like a synth
cab, since the synth panels will not move(much<G>), but the wood WILL
MOVE(at first; then it will settle into EMC-equilibrium moisture
content) with its surroundings. What this means is that Larry had
better make things a bit sloppy or tailor each cabinet to its
intended location for best long term "modularity" (means ability to
add and remove modules at will, without needing to deepen a rabbet;
or remove a finish...
I made my first walnut synth cabinet in the late 70's. Used boards
for the keyboard and module cabinet; with 1/2 walnut ply for the
bottom of the keyboard and back of the module cab. Ply is a good
choice for the back; as the width there is enough that without ply
(or some other type of construction designed for movement; like frame
and panel, or batten and board) the cabinet back will be always
fighting the sides/ends...
Hope this helps, Sorry for the verbosity,
Ballendo
P.S. Funny how when I mentioned making cabinets for you guys awhile
back, there was only one reply. I guess I'm just not in with the "in"
crowd.
--- In motm@yahoogroups.com, gareII@a... wrote:
<snip>Only the outer plys would be walnut, maybe a 1/16" or so. The
other plys would be something else,such as pine.
> Good cabinet grade plywood is readily available in
walnut,oak,cherry,and maple,to name a few.
>
> Gary