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Step 9: Cast the Inner Assembly to Make the Final Ring

Picture of Cast the Inner Assembly to Make the Final Ring
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Once you have your full mold made, cut a sprue out of the silicone and two small vent holes for bubbles to escape from as shown in the first two pictures. Put the inner assembly into it, with the chip facing 180 degrees from the sprue hole, then put together and wrap the full mold with two rubber bands.

Make sure they're not so tight as to deform the mold, just hold it together firmly. Then mix up your epoxy resin, THOROUGHLY. Make sure to mix for at least a few minutes, scraping any off the walls of the mixing container as you go. I used: and it worked well. Get a syringe and pour the epoxy into the syringe. Inject it into the sprue until it comes out the vent holes.

Put the whole thing into a pressure pot for no less than 24h at 60psi, this is to collapse the bubbles into solution so that there are none in your final ring.

You should be able to pull it out of the mold/wear it at 24h, but be gentle with it. That epoxy takes a week or so to fully cure and strengthen. Until that point, be careful with it. It will scratch and potentially even snap easily until full cure. When you cut the sprue and vent hole pieces off the ring, don't cut terribly close to the ring. 1/4" or even 1/2" away is good. If you try to cut flush with the ring body or even too close, it can break off below the ring surface. Just cut 1/4" or more away and then file it down. It's not worth it to try for closer after all this effort.