What is stabilized wood?
Stabilized wood that is to be used for knife handle material is wood
that has been impregnated with a chemical stabilizing solution. This
stabilized wood can then be worked with normal wood working tools.
Cutting, shaping and sanding will be similar to working with a dense
hardwood. The purpose of stabilizing wood is to make it more durable and
less prone to warping or cracking than natural, untreated wood. The
cost of a piece of stabilized wood compared to a natural, untreated
piece is usually about $10 more.
The stabilizing process.
Dry wood (preferably lower than 10% moisture content) is placed in a
container with the stabilizing solution. It is put under a vacuum and
then high pressure to insure that the solution completely penetrates the
pieces of wood. After the wood has been completely infused with the
stabilizing solution it is heat cured. This curing process turns the
liquid stabilizing solution into a solid.
What to expect from stabilized wood
Many knife makers look at using stabilized wood as an insurance
policy. Properly stabilized wood is more durable and much less likely to
develop problems in the future. Stabilized wood is also easier to get a
good finish because the stabilizing process tends to fill some open
pores and evens up the hardness of the wood.
Different woods will respond differently to the stabilizing process.
Some woods such as Maple, Ash and Box Elder will have a significant
weight gain from stabilizing often more than doubling in weight. Other
woods such as Redwood and Walnut will have a lesser weight gain and may
end up not quite as hard. When stabilized these woods are still much
harder and more durable than the natural untreated wood.
Working with Stabilized Wood
Working with stabilized wood is a lot like using natural, non-treated
woods. It can be worked using the same tools and abrasives as with
natural woods. The stabilizing process will even up the hardness of the
wood as well as fill in a portion of the open pores in the wood. This
makes the wood easier to sand and get an even finish that will often
times show off the grain patterns and figure in the wood better than the
results obtained using the same procedures with natural wood.
Not all stabilized woods will be the same hardness. Some types of
wood will not attain the same hardness as others. While the hardness and
durability are improved by the stabilizing, care should be taken when
working with them. Examples would be some Spalted woods, Redwood and
Walnut. These are best worked by hand after rough shaping. Power sanding
will remove material faster than harder woods so attention is required
when working with these.
Care should also be taken when power grinding/sanding stabilized wood
to avoid overheating the material. Using sharp abrasives and not
applying excessive pressure helps to avoid overheating. Once again,
paying attention to what is happening with the wood can help to avoid
problems. Overheating can cause warping and cracks much the same as when
working with other natural or manmade handle materials. Easiest way to
avoid problems is to throw away abrasive belts when they start to become
dull and take your time when sanding and shaping.
How to do fills
It is not uncommon to need to do minor fills with stabilized wood.
Especially when using burl. Different types of wood may have small
voids, bark pockets, open eyes or checks (shallow hairline cracks). Some
people choose to leave these unfilled calling it the natural character
of that piece. But if you choose to fill them it is a fairly easy
process.
Filling checks is very easy. Using thin CA glue run
it into the crack and allow it to settle. Then apply a little more so
the glue level is slightly above the surface of the wood. While the glue
is still wet take a piece of the last used grit sandpaper and sand the
area that has the checking. This mixes sanding dust with the glue to
fill the check and blend with the surrounding wood. Let this dry and
then sand any remaining glue from the surface of the wood. Done
correctly small hairline checks will disappear.
Small voids and open eyes are also fairly simple to
fill. Small ones can be filled with a couple drops of CA glue. Apply a
few drops of glue into the opening. After a few minutes the surface will
drop a bit as the glue soaks into the opening. Let that dry and then
apply a couple more drops. Repeat until the dry glue level is equal to
the surface of the wood. Sand away any dry glue on the surface of the
wood.
Larger voids can require just a little bit more
effort. Using epoxy mix with sanding dust from the wood and fill the
void. A flat toothpick usually works well for getting this mixture down
into the void. While this mixture is still wet, poke down into the void
with the sharp end of the toothpick to push it down into the opening and
to get rid of any air pockets. As the epoxy mix dries it will likely
settle below the surface of the wood. In that case you will want to
repeat this process until the dry mixture is level with the surface of
the wood. Finally sand away any dry epoxy that remains on the surface of
the wood.
Bark pockets are fairly common with burl. When
stabilized the bark is hardened but will usually have a small open area
surrounding the bark pocket. Fill the openings the same way as mentioned
for larger voids. But you might want to mix the epoxy with a dark color
sanding dust so the area filled blends with the bark instead of the
surrounding wood. The epoxy fill also helps to secure the bark portion
to the surrounding wood.
After your fills are completed you are ready to finish your wood.
How to finish stabilized wood
In the early days of wood stabilizing there were only a few different
types of wood being stabilized. These were light colored, small pore,
non-oily woods. Stabilizing companies would say all you needed to do was
sand and buff, no finish required. While this process can give a
reasonably good finish to the stabilized wood, you can finish it to look
a lot better utilizing slightly different processes.
There is not one process that will give the absolute best finish with
all stabilized woods so I am going to list a few methods to accomplish a
good finish. Then you will have some ideas how to adapt your methods of
finishing for the best results when finishing stabilized wood.
The very easiest stabilized woods to finish will be the light colored
woods with very small pores and fine grain. A good example would be
Maple. The quick and easy way is to shape and sand your handle to a
minimum of 1000 grit. You can go finer but if you stop at a lesser grit
you are not obtaining the full potential of the wood. Especially with
figured woods. Usually the finer you sand the wood the more defined the
grain patterns become. Think of it like focusing a picture. The lower
grits can look a bit out of focus while the finer grits bring the
picture into focus with a crisp, clear image.
This method is easy and works well on most
woods. After you have sanded as fine as you are going to, then blow off
any dust with compressed air. Then using an oil blend like Danish oil or
Tru-Oil apply a light coat of oil rubbing it in with your fingertip.
Wipe off any excess with a soft rag like an old t-shirt and let it dry.
Repeat until you like the way the wood looks. The reason to use an oil
blend is that it will fill very small pores with a finish that dries
hard, giving a smoother more even surface. This method tends to make the
colors more vibrant and adds depth to the figure in the wood. After the
final coat has dried apply a paste wax over the dry handle followed by
hand buffing with a soft cloth.
Medium grained woods such as Koa, Mango, Silky Oak and Sycamore can
be finished the same way as the finer grained woods.
Power Buffing - Unless you get it just right,
power buffing can burnish the wood eliminating a lot of the flash and
movement in the figure. Some woods will take on a smeared, muddy look
when power buffed. Coarser grained wood with larger pores tends to get
clogged with buffing compound. My opinion is that you can get a better
look by hand buffing and it is a lot safer too.
Maintaining the finish of stabilized wood.
Stabilized wood will keep a good finish much longer than natural non
stabilized wood. But over time you might want to freshen it up a bit or
maybe you will need to repair some scrapes or scratches.
If there is no damage to the surface you can usually brighten things
up just by applying a couple coats of paste wax followed by hand buffing
with a soft cloth. Much like polishing a pair of leather shoes.
If it needs a bit more than the simple waxing you can rub down the
wood with extra fine steel wool to remove any surface gunk. Then apply a
couple coats of an oil blend and allow it to dry. Finish with paste wax
and hand buff with a soft cloth. This method works out well with
kitchen knives and others that see a lot of use.
If the surface has scrapes, scratches or other surface damage you
will want to re-sand with a fine grit sand paper. After you have sanded
away the surface damage follow up with a couple coats of the oil blend
followed by paste wax and hand buff.
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