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Gene Larson's Shop Notes |
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Cutting Logs and Planks
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By: Eugene Larson |
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It
should be realized that there are many excellent woods available in addition
to the highly coveted English boxwood. As our Washington club member Howard Chapelle said, and echoed by Merritt Edson
when he was Secretary of the Nautical Research Guild, woods such as maple,
cherry, and holly make beautiful models, and in are of equal status with box
wood. They both suggested that model builders use these woods local to us in
the In
order to pursue this endeavor you must realize that you need the proper
equipment and know how to use it safely. There is a considerable investment
involved if your only purpose is to produce model building woods as you will
realize as you read further. I
have harvested many interesting logs from various locations. I found apple in
an old orchard to be replaced in West Virginia and a cousin's home in
Wisconsin, walnut from a farm in Northern Virginia and our lake home in North
Carolina, cherry from my brother-in-law's farm in southern Maryland, basswood
and pear in a backyard in Alexandria, holly from a street development in one
of George Washington's old farms (probably an original tree based on the
size), Yoshino cherry from storm damaged cherry blossom trees on the D.C.
mall, and silver and sugar maple, pine, cedar, plum and oak from our NC home.
When
you run out of those types of sources you can search the specialty wood
stores for more exotic species. However, use caution in selecting your wood.
It can be very expensive and you need to be sure the quality you want is
consistent throughout the plank you choose. In some cases the mills subject
the woods such as walnut to a boiling process to spread the dark color in the
heart wood into the light colored areas of the softer sapwood. This has an
effect on the original rich color of the heartwood. This misleads the
customer and you can end up with a lot of expensive scrap. Also, the planks
in wood stores usually are rough cut, not planed smooth. The surfaces of
these planks age quickly, and it is difficult to tell the grain pattern and
the amount of sapwood. This is especially true of cherry. The greatest
advantage of store bought planks is they are already dry. Several
factors to realize are: This
"logging" process takes time to do and to wait for the wood to dry.
There
is probably up to 50% waste by the time you get to the final pieces of
modeling wood. The
cost of tools can be high. You
potentially could be tagged as a purist. The
final satisfaction is high. The anatomy of the tree is important to understand. There have been many articles in wood magazines on the subject, and there are numerous web sites on the subject. I will only touch on the more important aspects. |
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The three typical cuts that can be made in a log.
The quarter sawn is the most stable, and usually gives a straight grain
pattern down the length of the plank. The flat sawn will usually cup up on
the ends as it dries (as shown in this location), and will have a more
pronounced grain down its length. The rift cut will come out somewhere in the
middle. The
entire log could be quarter sawn by making all radial cuts, but that would be
a very large project, and the rift and flat sawn sections do have some use
after thorough drying. |
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The initial log as the tree is removed. This happens
to be a large oak tree in Note
the absence of knots in this log from the lowest portion of the trunk. This
wood was harvested for "furniture" pieces. Oak is not suitable for
exterior wood on ship models due to its pronounced grain which is not to
scale and is difficult to fill to a smooth finish. It can be used for
strength members on ship models in locations where it will not be seen. |
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The 22" diameter log was reduced in length to
five feet. It still weighs much more than even two people can pick up due
partly to being "wet", The quartering process has begun. Note
the sap wood (light color next to the bark, and the darker colored heart wood |
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The quarters are then cut into slabs about 4"
thick. The second slab cut in each quarter of the log is made perpendicular
to the first to keep grain as much as possible in the "quarter
sawn" orientation. However it does approach the "rift sawn"
condition in some areas, The
pieces to the left are "scrap" for fire wood. This
same principle can be used on any size log. Just scale down the size of the
cuts to fit your needs. Typically the plank thickness would be between
1" and 2". |
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The oak slabs are stacked with spacers (called "sticks') to permit air circulation. The rule of thumb is to allow drying of one year per inch of thickness if no "forced drying" is done. Note that the ends of the slabs have not as yet been coated with sealing wax. Note also the sap wood at the right edges of each slab. This will be trimed off, thus removing the unwanted bark. |
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Some black walnut lumber harvested in North Carolina
from a rotting tree. (Walnut and holly trees are much more desirable when
they are alive and growing.) Note the white areas are sap wood that must be
removed in the final cutting process. These slabs were harvested four years
ago, and even without end sealing only one split can be seen. Due to the poor
condition of the tree, there are areas in the walnut that are not usable due
to knots, rot and staining. The better pieces have already been used for a
model case base, decorations (cross), etc.
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Typical cutting of an 8" log into 1" thick
approximate quarter sawn planks. The plank grain actually ranges from quarter
sawn to rift sawn. Keep
in mind that the final piece of wood required for a ship model is typically
1/4" x 1/16", but usually not over 3/8" thick. This is smaller
than the size of this "o" in the drawing. |
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A stack of sugar maple that has been drying since 1997. The layers are separated by plastic strips. The ends have been sealed. Note the species and date of cutting are marked on each piece. |
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The Final Step Plan
ahead so your final cuts are approximately as shown in either drawing. The
drawing represents final planks of 1/6" thick by 1/4" wide, This is
typical of planks required for ship models. See separate shop note on one
process for achieving the final planks. The upper cutting process is well
suited to representing deck caulking by, prior to cutting, coating the
"top surface" with dark pencil, varnish and then black paint, or
black craft paper, depending on the model scale and thickness of the
caulking. |
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Wood ready for a model. The model is a Chesapeake Bay Oyster Sloop at a scale of 3/8" = 1' (1/32). The long cherry strips for hull planks are 1/16" x 1/4" (2" x 8"). The holly deck planks are 1/16" x 1/8" (2" x 4"). The holly has black craft paper glued to one edge to represent deck caulking. Note the larger pieces of uncut holly with the black paper attached. |
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Reference:
See the following web page for more specifics on log
cutting |
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Reference:
Wood Magazine issues 155,
156, 157 and 158 (May, June/July, September, and October 2004) had a four part
article on understanding wood. Perhaps you can find copies in the library or
on the web. A
great example of the beautiful "flat sawn" patterns available on
some woods such as walnut and cherry is the veneer cut from the logs. The
cutting process involves very sharp blades slicing off sheets of wood like
unrolling paper towel. These are the patterns not desirable in model
building. Generally
you only want to keep the heartwood of any log. Usually the sapwood is softer
and a different color. I also avoid the very center of the log The pith, and
try to work around knots. If you can manage to get a log from the bottom of
the trunk it should generally have fewer or no knots. It
is not necessary to remove the bark from the log as it will become a part of the
scrap wood as the cutting progresses. It will usually be removed with the
sapwood. Also I recommend cutting the log down to the minimum size you think
you will need. There are two reasons for this. One is the wet wood cuts much
easier than dry wood and is not as rough on your saw blades. The second
reason is that the wood will dry faster in the smaller dimensions. However,
leave sufficient material to allow for warpage,
twisting and bending during drying. The
initial cuts you make in a log are not critical to the desired final grain
pattern of the model wood, especially if the log is large. It is advisable,
however, to plan ahead. The
quarter sawn rule is not absolute. There can be some degree of rotation to
flat sawn without greatly electing the pattern or the tendency to warp. Every
piece cut out of a log cannot be exactly quarter sawn. For
large logs I use a chain saw to make the longitudinal cuts. This is very
imprecise, but a magic marker guide line helps. The surface will be very
rough, uneven, and probably curved. Cut slabs and chunks of the log down to
approximately If
the log is in the 6 to Continue
cutting the wood down to the minimum possible thickness based on the final
usage. For me this is usually one to two inches thick and whatever width
comes out of the cutting process. There
are mixed opinions regarding the need to "seal" the ends of the
wood prior to the drying process below. Some woods, especially when extremely
wet when cut, have a tendency to split along the grain several inches into
the billet. This is due to the end grain drying and shrinking faster than the
rest of the wood. Rather than experiment with what wood will and will not
split as they dry, I always seal the ends. I usually use wax, or paraffin as
it is called in the home canning process. I melt the wax in an old pan
carefully on the stove, then take it outside and dip the ends in about an
inch. When in the "field" without the wax readily available I will
use anything around that I think might work such as shellac, varnish, or
regular paint. These do not work as well as wax as it has been proven and
reported in woodworking magazines the paint/varnish finishes are not a
complete moisture barrier when used in furniture applications. However they
are a help and the wax treatment can be accomplished later. Now
stack the wood in a dry, out of the way location, and allow the drying
process to take place, with the rule of thumb of one inch per year. This can
be expedited somewhat if a fan is directed on the stack and left running. In
stacking the wood use layers, and place thin pieces of the same wood (or
plastic) across each layer to permit better air circulation. A different wood
for the "sticks", as they are called, could create stains in your
wood. When
the wood is dry it is ready to process into model planks. Now you can go to
the shop note on Your Own Lumber Mill on this web site. Just realize that you
will still need a band saw, a jointer, maybe a planer, maybe a Have
fun with woods! |
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