How not to make a cool wood-and-epoxy gemstone ring

How not to make a cool wood-and-epoxy gemstone ring

Obligatory finished shot
This was probably the most physically difficult part of the project. You need to break some kinda-thick wood. Wood is not easy to break. I set up some plywood and my project wood (black walnut) in my bench vise and just kept tightening until it broke…
Which it did violently. Like, I thought I had broken my vice. The walnut did not go quietly into the night.
From here, it's pretty easy to finish the break with your hands.
The broken wood, with all that fun interesting texture at the top.
Apply wood glue. I used Titebond II, but any waterproof-ish wood glue should be fine.
Spread it evenly. Unglued spots are weak spots!
Smoosh the pieces together. Try to keep the seam even. I failed. For the record, you don't *have* to glue the pieces together. I only did because I was hoping I could get three ring blanks out of this piece of wood, and wanted to epoxy it all at once. I still only got two. 🙁
Clamp! Tight. Wood clamps are the best thing. If you're going to do woodworking, get clamps. Lots of clamps.
After the glue is dry (give it 24h or so. Just follow the directions on the bottle. They're all different), you need to smooth out the seam to prevent leaks in the the epoxy step. Again, this gluing was overkill. Did not need to be done.
Next, apply masking tape around the top, higher than any of the peaks. This will be your epoxy … mold. Kinda.
Mix up some two-part epoxy. Color it somehow. I used Ultra Glo finish epoxy and fountain pen ink (Arabian Rose). The ink was probably not a great idea, as it adds moisture (moisture is bad in epoxy, I think), but it seems to have worked. YMMV.

Mix your epoxy *really* well, btw. Better than you think you need to. Usually, bubbles are fine. I ran into some issues, I think, due to the nature of this pour, but I'll explain soon.

So, this epoxy is supposed to take 72 hours to fully cure. This took less than 24 hours. I *think* it was because it's usually meant to be poured at like, 1/4" thick, for finishing woodworking projects. When you pour it thicker, there's an exothermic reaction, and the heat accelerates the process significantly.

The thicker pour and fast cure, I think, trapped a ton of air bubbles in the epoxy, making it cloudier than I'd have liked. In a thin pour, some bubbles are fine, as you can just breathe heavily on them to bring them to the surface and pop, or run a blowtorch over the surface at a distance to do the same. Here, the bubbles were too deep for that (a blowtorch did smooth out the top surface, though).

For my next attempt, I'll do the pour in stages, I think. Getting the color to match through the stages will be hard, but might be a good opportunity to do some color gradients.

Wear a respirator for this step. Epoxy dust sucks. It is not good for you. Plus, sawdust causes lung cancer, so wear a mask whenever you sand.

Anyway, smooth out the piece (my tape mold bowed a bit, as you can see in the previous post-pour picture). This step is where I remove that bulge in the epoxy, and, even though I didn't remember to take a picture, this is also where I added the facets to the "stone". I used a belt sander for both steps.

For the facets, just pick random angles and hold it steady against the sander to make cool shapes. Keeping the piece steady makes the facets flat with sharp corners (which get rounded off later, so keep them sharp now). Try to keep your facets kind of big, and don't do too many. I'll explain why later.

Cut the exterior curve with a band saw. I marked the interior and exterior with a compass. These lines eventually meant basically nothing, as I changed the hole position a bit.
Forgot to take a picture of drilling the hole, but… drill a hole. I used a forstner bit and a drill press, but there's no real reason you couldn't use a hand drill. Or lasers. Make a hole.

In this part, I'm sanding round the edges with a "sanding mop" (just a bunch of sandpaper flaps stuck together that spins). Totally unnecessary. Just easier and something I had. Just hand-sand it. Whatever.

Here, I'm using a pencil wrapped in sandpaper to smooth out the inside of the ring hole. Sometimes you don't have all the right tools, so you make do.
Now we get to polishing the "stone". This is 150-grit sandpaper (well, it was supposed to be. I screwed up and started at 220), stuck to a flat piece of granite with water. Keep the sandpaper wet while you do this. You still don't want to breathe the epoxy dust.

Anyway, this is why you want the facets big. You're going to be holding each one against the sandpaper, then rubbing it around. That's basically it. It just sucks when you've got like, 10+ facets, some of which are too small to be able to feel if you have the sandpaper just right on them.

I ended up using 150-grit, 220, 600, then switching to a set of polishing pads called Micro Mesh. Basically, just keep wetting and sanding.
This is at the start of the micro-mesh. The white spots on the ring are bubbles in the epoxy that I've sanded down to. They'll mar the finish at the end.
Anyway, this is after all of my sandpaper and micro-mesh, then rubbed with some mineral oil. I also hit the epoxy with a little bit of plastic clarifying compound from a car headlight clarifying kit. It didn't help. Probably needs to melt the plastic a little, and couldn't, since this is a different material.
Ultimately, I'm happy with it, but the epoxy is not nearly as gem-like as I would have liked. The bubbles inside contributed to this, but I also just couldn't get it quite glossy enough. Changes in the polishing technique might help. Not sure. I also used an epoxy that's a little softer than others, so it just might not take a shine as well.

Another option, that I think I'll try next, is to shape the "stone", then just pour fresh epoxy on it. That stuff is glass-like before you sand it, so an extra, exterior coat might save a ton of sanding time. I'm just not sure how to blend it with the wood. Maybe just with a brush.

I also did not make the ring *nearly* thin enough. Nobody would want to wear this. I'll get it thinner next time. A little less color in the stone, too, to make it more transparent.
Anyway, thanks for reading!

Source : rootyb from Reddit