This Shadowbox clock is created from a cottonwood burl leftover from my Jet Engine Coffee Table Project, a Shou Sugi Ban-finished frame, and a Copper Sheet from K&S Precision Metals that I patinated using fire, water, and Borax.
Special Thanks to K&S Precision Metals for Sponsoring this video.
Here is a link to the Copper sheet I used
and the Borax
The Shou Sugi Ban Frame is made from white oak. I like how the grain of the white oak shows through the char left behind in the grain. On the front edges, the ray fleck that is traditionally seen on quarter-sawn oak shows through beautifully. You can see this in the video section, where I trim the clock’s second hand to fit. More on my Shadow Box Clocks
 The Build Process
I used white oak for the clock’s frame. This wood burns well while retaining its structure, and you can see the grain of the wood through the char. When I did the layout for the frame, I took care to keep all the boards in order so it looked like the grain pattern wrapped around the frame.
I made two rabbet cuts at the table saw. The first one will create a reveal to hold the burl wood. The second will create a ledge to hold the copper back. 
Now that I have the rabbets cut, the workpiece doesn’t sit flat on the table saw top, so to keep it flat and safely cut it, I used a spacer block to stabilize it throughout the cut. Yes, I could have cut the miters first and then cut the rabbets, but that didn’t feel safe as I would be using a push stick on an angle’s edge to cut the rabbets, which could have resulted in the push stick slipping down the miter.
I clamped a straight edge to my workbench to give me something to push against and line the workpieces. I then used blue tape to hold them together, allowing me to clamp the miters tight after adding the glue.
I used basic wood glue for this glue-up.
To add strength to the miter joint, I cut slots in the miters to glue in some splines, adding a cross-bond to what is mostly an end-grain joint.
These splines add considerable strength to a miter joint, sometimes called miter keys.
Then, I added the Shou Sugi Ban finish. I did a light char as I didn’t want to warp the wood or have the miter joints pull apart.
Moving on to adding the patination to the copper, I mixed up a solution of Borax and water to quench the metal once hot. I added borax to saturation until it stopped dissolving into the water. The borax quench will make the pink coloration we are going for in this project.
I also sprinkled borax on the copper after abrading and wetting the surface. This will mask off some areas from the air during heating and the dissolved solution, creating a cool texture and pattern.
I heated the copper with a weed-burning torch and watched the color change. From my test pieces, I wanted them to become red before quenching them.
After quenching the copper, these are the colorations I got. I think this will make a really cool backdrop to the burl wood, as it has a similar pattern to the grain.
After some final assembly, the finished clock. This is a great example of where wood meets steel.
I’m the owner of Benham Design Concepts, a mixed media art studio where I design and build custom furniture and other works of art using wood, glass, stone, and various metals.
In this blog, I talk about the art I create, my journey, and the things I learn along the way.