As mentioned earlier I was considering adding a band of
turquoise inlay around the center where the two halves join. It seems like a good idea but there are times
that what seems like a good idea isn’t.
To hedge my bets a sample piece sounded like a good way to go. Taking a small leftover piece of the oak I
turned a disk similar in shape but at a much smaller scale and added a narrow
groove. You can’t see it in the photo
but the groove is undercut. By that I
mean the sides are tapered so the bottom is wider than the opening. Just a little extra insurance to form a wedge
to better hold the material in place.
The inlay isn’t really turquoise laid into the groove but
is a synthetic set in what I believe is a polyester resin. I started by giving the groove a good blast
of compressed air to make sure it was clean.
Next is to weigh out ½ an ounce or because I was using a metric scale,
14 grams of the matrix, add 8 drops of the harder and mix well. The consistency ended up about like
applesauce almost thick enough to hold its shape but not quite. Using the wooden stirrer, I packed the
material into the groove turning the lathe a little at a time working my way
around the piece.
Unfortunately, the material was not quite thick enough to
stay in the groove and it slowly started ooze out the bottom. The good news is that the working time of
the mix is not very long so I spent the next 10 minutes or so slowly turning
the lathe by hand until the material had setup to a point where it would hold
its shape.
After giving the material a full day to cure it was time
to try my hand at turning it. Since I
was not sure how it would work first was to sharpen the lathe tool, crank the
lathe speed up to about 1,200 RPM’s then using a light touch begin turning the
excess away. Surprisingly it turned very
easily and smoothly. When done removing
the excess material I was left with a seamless turquoise band the shape of the
groove with sharply defined edges and no staining of the oak. Last is to sand the piece up through 320 grit
except for the turquoise band. For it the
final grit is 800.
The next step is to duplicate the finish used on the
actual piece; dye in alcohol, a coat of lacquer to seal, and the gel stain to
fill the pores. The impact on the
turquoise band is slight I believe mostly due to the slight amber color of the
lacquer. Here it is ready for the final
coats of lacquer. I am happy with how it
looks and will probably go ahead and do a similar banding on the actual
project.
As I was about ready to put the lacquer top-coat on it
seemed like a waste to just throw it away when done with the test. A little thought and some doodling led me to
decide to try to add a finial to the top and a base that would fit into the test
piece mounting hole at its bottom.
The finial is the first piece to be turned starting with
a roughly ¾” square by 5 ½” long piece of cherry. Why cherry rather than oak? Well, because I want the finial to be pretty
thin and delicate, I needed a finer grain wood than oak. Here it is pretty much done except for the
final work on the tip at the right and being cut off at the base of the tenon
on the left. While it does not show up
in the photo the base is undercut so it conforms to the curve of the top of the
test piece.
I needed a ¼” hole centered in the test piece to glue the
finial in. That’s accomplished by
remounting the test piece back on the small jaws which lets me easily drill a
centered hole in-line with the test piece’s center axis.
Next is the base.
A small piece rough cut to a circle is mounted between centers then
turned round. Once round the chuck with
the small jaws is mounted on the lathe.
What you see in the photo is the tenon that will fit in the hole in the
bottom of the test piece. That hole was
for the small chuck jaws to expand into and hold the piece in place. Again, the first step down is undercut so
there will not be a gap between the base and the test piece when it is glued in.
This photo shows the tenon fitted and ready to start
working on the transition to the flared part of the base.
When the transition is pretty well done the base is
removed from the chuck, flipped end for end and the chuck jaws use the newly
turned tenon to hold it. Now the bottom
can be turned getting rid of the drive spur marks leaving a nice smooth bottom.
Because there is a fairly small space where the base and
the test piece come together, I decided to finish them separately before
assembly. Here they up on stands ready
to be sprayed. I put them on stands to
get them off the cardboard which helps minimize getting any dust kicked up by
the overspray. The blue tape will keep
the lacquer off providing raw wood for gluing.
After the lacquer cured overnight the base and the finial
gets glued on. Later that day the top
half of the test piece and the finial get a couple coats of lacquer. I know that I went off on a tangent in what
was supposed to be a simple test of the inlay material and method. Nevertheless, since I don’t have to make a
living at this, I can follow wherever the project leads me. Besides, I like way this little piece turned
out.
Next up – Glue-up & Finishing
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