This post is a cousin of a previous one in which I made a clock out of my firehouse patch. Instead of a clock, this time I wanted to make a large medallion (about 18" in diameter) to inset into our kitchen tables in the firehouse. Instead of dying the individual pieces in various colors as I did with the clock, I wanted to do an inlay pattern with different species of wood. Due to its prominent and highly visible location in the firehouse, I also wanted the finished product to be nearly or completely seamless.
The kerf adjustment hell this would unleash, combined with my somewhat successful, but not perfect attempt at seamless marquetry in the past prompted me to try something different. Instead of trying to shrink the seams to near zero, I embraced the gaps. I became the gaps. I left them nice and wide. The idea was to pour black epoxy resin into all the negative space to create the seamless look I was going for.
After gluing all the pieces down to a nice thin flat piece of mdf, I worked a thin seal coat of clear epoxy down into all the grooves and over the entire surface. This kept bubbles from forming in the final epoxy pour. It also kept the dye in the epoxy resin from leaching into the wood fibers.
After about 6-7 hours to let the seal coat cure a little, I filled all gaps and negative space with a black epoxy. There was quite a bit of overpour and there was epoxy resin everywhere (sadly I forgot to take a picture of this), but all gaps and recesses were successfully filled above the level of the wood. Honestly, it was easier to work with than I anticipated. I spent about 15 minute with a torch popping surface bubbles as they formed and then let it cure for about 24 hours. After it cured I used my router in a surfacing sled I built to remove most of the overpour and finished it off with some light sanding. Overall very pleased with the results and can see this technique being very useful for all sorts of projects in the future.