Introduction: Fossil Inlay Table
150 million years ago a creature bridging the gap between dinosaurs and birds fell to the ground, died, and was covered in layers of earth. Minerals replaced its bones over the millennium, forever preserving its form. After this unimaginably long rest people extracted this form, and digitized its image. Finally, in May of 2014, I placed a sheet of tracing paper over my monitor, captured the image of this fossilized creature, and recreated it in ebony and curly maple on the surface of a contemporary end table.
I do not give exact dimensions for this project as they are not critical, and can be approximated by someone attempting this build. Furthermore, I describe the steps in this build as I completed them, but multiple techniques to obtain the same result are possible. If you do not have a tool I use then focus only on the end result, and perhaps you'll find a different way to get there.
Step 1: Make Slats for Laminated Legs
The legs for the table start as 7/8" thick sapele that must be made into slats so that they can be glued together in a curved form. Dimension these slats for length on the miter saw, and width on the table saw. Glue these boards together in pairs of two with a piece of similarly dimensioned scrap wood in between. Next, dimension for thickness at the band saw, (the scrap wood in the middle allows for full use of the sapele without getting fingers or push sticks too close to the blade).
Step 2: Bent Lamination Glue Up
Glue the slats together by first laying them edge to edge, and spreading glue generously on one surface. Then stack them up, and place them against a curved MDF form that is covered in tape to keep glue squeeze out from sticking. Use clamps to bend the slats to the curved form, and hold them in place while the glue dries. In the picture you will notice an additional stack of longer, unglued slats that is placed against the glued slats to spread pressure from the clamps. Glue squeeze out should be visible at every point along the length of the stack.
It is worth noting that I did not sand after making the bandsaw cuts, the faces of the slats still had the kerf marks from the saw blade. I found that this did not matter structurally or ascetically, but you will want to make sure that you bandsaw blade does not leave particularly deep kerf mark before you decide to skip sanding. Alternatively, you could cut the slats on the table saw which leaves much cleaner faces, but wastes more material.
Step 3: Bent Lamination Clean-up and Dimensioning
After the bent lamination glue has dried the rough forms need to be refined to the final dimension of the table legs. Before taking the legs out of the form decide which end of the form will be the feet of the legs, and mark the legs accordingly. This is important because the form will not be perfectly symmetric, and joinery is easier if the asymmetry is consistent. Remove the bulk of the glue squeeze out with a belt sander, then pass the legs over the jointer to flatten the surface. Then use a planer (not pictured) to dimension to final width. Finally, clamp the legs back in the bending form and make two cuts with the miter saw on each end of the leg. Make sure that a flat surface on the bending form registers against the miter saw fence, this ensures that the top and bottom surfaces of the legs will be parallel after the miter saw cuts. Also, stops clamped on the miter saw fence ensure that the length of the legs will be exactly the same, so that the table top will be level. Make sure you mark the leg feet again, if you are cutting your marks off with the miter saw.
Lastly, a flat area has to be created on the the inside curve of the legs to meet up with the floating box. Make no mistake, this is a bit tricky, do not assume that each of the legs is exactly the same, there will be subtle differences in the curve. Use a square to mark a line perpendicular to the feet of the table, intersecting the leg at two points a bit (1/2") further apart than the height of the floating box. This will ensure that each of the legs has a bit of extra flat area so the are no gaps between the box and the legs, even if the curvature is not perfectly Identical.
Step 4: Floating Box
The center box of the table is made from three identical pieces, each with 30 degree miter saw cut ends. Each of the three sides is about 8 inches long, and 4 inches wide. Glue these three pieces together with strap clamps, and flatten the three corners at the disc sander. Cut the bottom out of 1/4" stock on the band saw, glued to the three sides with clamps, and flush trim (using a bearing guided flush trim bit) at the router table.
A top for the box is made by gluing a thick wood piece with inside dimensions of the box to a thin wood piece with the outer dimensions of the box. I drilled a hole and installed a handle, the one I found was actually a rock, to compliment the prehistoric fossil theme.
Step 5: Splines
The joints at the corners of the floating box are not yet very strong. This is corrected with six splines, two at each corner. Use a table saw jig that holds the box with a corner flat against the table, and cut recesses for the spines. Depending on how thick you want these to be you might need to make several passes, I chose to make them the same thickness as the bottom of the box, so that I could use scrap pieces to make the splines. Glue the splines into the recesses.
Step 6: Table Top
I would recommend not determining the final dimension of the table top until after the box and legs are constructed. Then it is simple to lay these out, and determine what size of table top will create a desirable overhang from the legs.
The table top is is triangular, and consists of three pieces. It is important that the grain of the wood is be parallel to the circumference of the table. This is pleasing aesthetically, and ensures that wood movement will not cause the edge banding to break off (wood expands and contracts across the grain, but not with the grain). The angled cuts for the three pieces of the table top are a bit tricky, I made them at the table saw with a table saw sled, and had to make multiple passes to get the three pieces to come together without any gaps. Use biscuits or dowels on the seams to hole the table together, but do not put these too close to the top, as they could be exposed during the carving and inlay. I made the table about 1" thick.
Step 7: Inlay
To begin the inlay, first find an image that you like, and draw it onto tracing paper (I placed the tracing paper directly on my monitor, and drew the picture, don't press too hard if you do this!) Next, use carbon paper to draw each piece on strips of ebony about 1/8" thick. Cut the pieces out with a scroll saw, and use a rotary carving tool to shape each piece with rounded but somewhat jagged edges, so that it looks like a bone. Use carbon paper to trace out the image on the table top, then use double stick tape to stick the bone pieces in place. Use a hobby knife to cut a small grove around the parameter of the bone piece. Next use a plunge router with a small bit to excavate a recess for the bone piece. This should be about 1/16" deeper than the thickness of the bone piece. Glue the piece into the hole with tinted glue, so that squeeze out is not noticeable, and repeat these steps until the image is finished.
Note: hang in there, this is tedious, but can be done in a day, try and find some good podcasts or audio books to listen to!
Step 8: Edge Band
The outside of the table top is edges with 1/4" sapele. Steam bend these strips before gluing them on. This can be done with a standard steam bending kit., once they have steamed for 30 minutes they can be bent around pegs to impart a curve to match the table. Expect that they will spring back to have of the peg curvature, so make the peg curvature twice that of the table. Some creativity is needed to clamp these to the table for the glue up, I used a curved MDF piece, some flexible strips of wood, and a wood block to direct the clamping pressure to the table and not the fragile partially finished edge band (see picture, this is most challenging for the last long strip. Since the table corners are flat rather than pointed 3 small edge band pieces were needed to completed the perimeter edge banding. When the glue is dried I flush up the edge banding with a hand plane and flush cut handsaw.
Step 9: Carve and Epoxy
Use a carving gauge to excavate around the simulated fossil. Your goal is to make it look like the bones were buried in the wood, and you exposed them as an archeologist would have, so let this concept guide your hand as you work. Make sure that all of the carved area has been lowered under the original plane of the table, it will not look good if wood is poking up through the epoxy.
I used EnviroTex Lite epoxy to fill the carved voided space. Ensure that the table is level perfectly level, mix the two epoxy portions, and pour over the table. When I did this project I filled only the void left from the carving, but this created a "seam" where the epoxy ended and the regular table began. If I had to do it over again I would use painters tape along the outside parameter of the table to create a 1/16" wall. This would allow the epoxy to be poured over the entire table, and thus void the seam. The transition to the normal finish could be dealt with at the edge where it is harder to see
Step 10: Assemble and Finish
Drill holes through the splines in the box that are large enough to allow screw to pass through without the threads catching.
Clamp the legs to the box, and carefully position the legs and box so that each of the legs is level (pointed straight up), and the box is level as well. Mark the legs where they meet up with the holes in the splines, and drill pilot holes in the legs for the screws. Also, use a dowel jig to drill 3/8" holes on the upper legs for dowels to joint the legs with the table. Glue and screw the legs onto the box, then use dowel centers to locate points to drill 3/8" holes in the table top for dowels. Glue the legs and dowels together, apply pressure by stacking some heavy objects on the table.
Sand the table to at least 200 grit everywhere, and 2000 grit on the top. Further polish the top of the table with 5000 grit pads, followed by polishing compound. Apply the finish of your choice, I used several coats of thinned polyurethane.