For full details on how to get the very best shine from using the National Geographic tumbler, I came across this great YouTube video by a rock tumbling expert: https://youtu.be/CsTc1kXUuPo
His detailed advice:
- Tumble better rocks: hard rocks, all the same type at a time in the drum
- Tumble slower
- Take it slower on the first stage: run more times to remove flaws (3 days at a time at speed one)
- Use ceramic media mixed with the rocks after the first stage
- Use quality polish - 1200 aluminum oxide as final polish
- Keep the barrel at least 3/4 full
- Always wash rocks and scrub holes and cracks with a toothbrush then run through borax for a few hours
- Use 3 tablespoons grit per bin at every stage
He inspired us to order 1200 aluminum oxide polish, ceramic media, and borax from Amazon. We're going to run the polished stones through a borax cycle and then we will use the polish and ceramic media to see if we can get them shinier.
We will tumble some stones in there, all the same kind at a time, with the ceramic media taking it up to 80% full in the bin, and we will let you know what happens.
Update from weeks later: any shinier?