My wife asked me to make a set of these. The wood is walnut (no stain, that’s the natural colour). The fill is Ecopoxy flowcast epoxy with a seaform green metallic tint. I had to figure out a good way to keep the stock clamped down to the wasteboard without bulky clamps getting in the way. I wanted to maximize the use of the material since it’s expensive stuff.
After a couple near disasters where the workpiece lifted and I had to hit the emergency stop button, I ended up using two layers of blue painters tape with CA glue in between. That held the piece down well against the force of the upcut spiral bit.
Here’s the wood and epoxy in the form:
Then after resawing it in half to make two sheets, about 8mm each and lots and lots of sanding:
Here’s the last little bit of cutting the second sheet:
I cut the little holddown tabs with a razor blade and sanded the edges. Then I soak them in mineral oil and finish with a beeswax and mineral oil finish.
Here is a set of the square shaped coasters: