Inlaying the turquoise into the recess is next. The inlay consists of an ultraviolet cured resin used as a carrier and bonding agent for the fine turquoise granules. The photo below shows the resin, turquoise granules, a small UV light for curing and the small spatula used for mixing and application. Process is to mix the turquoise with the resin at about four parts resin to 1 part turquoise then carefully put it in the recess. Because the turquoise granules block the penetration of the UV light three layers are needed with each cured separately.
Here is the first layer application in progress. The small spatula is used to fill the recess about a third of the way full. Once the recess is partly filled the mix gets cured using UV light. The process requires a slightly different mindset since it’s not like epoxy, other types of glue or fillers that have a working time where all too frequently one is up against the time limit to get what needs to be done before the material sets. Not so here because the mix of resin and turquoise does not harden until it’s exposed to UV light. 
In other projects I have used a small battery powered UV flashlight and it works OK but does take some time to get the resin to cure because the light is not all that intense. Here in the Southwest, we do have a rather large natural UV generator – called the sun. It’s not that usable in the summer due to the heat and the potential for causing problems with glued up pieces. However, this time of year the UV radiation is still high but the weather is much cooler. My process is to sit in a lawn chair with the turned blank in my lap facing the sun while the UV flashlight helps the curing along. The photo below shows the first layer cured.
Once all the needed layers are in place and cured the body gets put back in the lathe and the turquoise inlay gets turned down flush with the wood. The whole part is then sanded smooth with the turquoise being sanded up through 800 grit dry paper. The next step is to start cutting the recess the oak blackwood accent piece will go into. The top drawing shows the area where the recess will be cut greyed out. The bottom photo between the two arrows shows the initial starting cut.
Here the recess is mostly done with the depth good and the width almost to the finished dimension although to give a margin of error when the center section gets cut out later it does need to be made a bit wider. I will explain why when I get there.
Drilling the reference hole deeper is next so it is available later on. The required finished depth from the face is ¾”. To drill that I first set the tailstock to show a one-inch extension shown in the top photo. The whole tail stock is then moved until the tip of the drill bit is at the edge of the ruler which is tight against the face of the body. 
Drilling the hole to the proper depth is a simple matter of turning the hand crank on the tailstock until the gauge reads 1 ¾” as shown in the top photo. The bottom photo has the completed hole drilled ready for the 2 ½” hole to be drilled down so it’s about 1/16” deeper than the bottom of the recess. 
With the center hole drilled to depth the material between it and the recess is removed and cut a little bit deeper leaving the bottom of the recess just a tiny bit higher. The bottom of the recess marked with the red arrow is then very carefully flattened. In the photo you can see that there is no light shining between the ruler and the bottom of the recess meaning the bottom is flat and in a single plane. Moving toward the center there is light between the ruler (at the 2” mark) and those surfaces meaning that there is clearance. This is so when the blackwood piece gets glued in, I only have to worry about the piece lying flat along the outer red arrow marked surface.
With the recess cut to size the first oak blackwood insert can be started. In the top right the red arrows point toward the two finished blackwood inserts. They start out as a glued-up blanks. The top left shows the first one being glued up while the bottom photo shows it being flattened using the thickness sander.
Once the oak blank is flattened a circle slightly larger than the finished insert is cut out on the bandsaw. For symmetry in the finished piece the disk is centered on the glue joint between the two pieces. The joint is a little hard to see because both halves are from the same board and adjusted so the grain matches up pretty well.
Once bandsawn a 2 ½” hole is drilled centered on the disk just like I did earlier on the main body blank. After mounting the disk in the lathe, the face gets aligned so it runs true or as close as I can get it followed by taking a very fine facing cut to bring it truly square. Turning the outer edge flat and square is next. Once that’s done a very shallow cut leaving a raised circle is very carefully turned down until it just fits inside the recess cut in the body. The red arrows point the this. Note that the edge is at a slight angle. This along with some trial and error lets me sneak to a perfect fit where the body will fit over the slightly narrower outside edge but the inside is still a little too big. 
With the outside diameter set a tenon needs to be turned to exactly match the depth of the recess in the blank. I got as close as possible measuring with the dial calipers overshooting the tenon length by a few thousands of an inch leaving a tiny gap between the lip and the turquoise. From there the tenon is carefully shortened until the lip on the piece just touches the turquoise band. Accomplishing this took quite a bit of trial and error because I couldn’t see how the tenon was to fitting to the bottom of the recess. 
Here is what the oak blackwood piece set into the body looks like. It’s not black yet but it will be when dyed with India Ink. There is still quite a bit of turning and other work before this piece can be installed but it gives an in-progress idea of how it looks.
Next Up – Turning, Dying & Gluing in the Oak Insert Profile – Part 2
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