Refining rock tumbling 📝

Refining rock tumbling 📝

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:

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.


Polly Plastics final polish 1200 fine aluminum oxide

Ceramic media:

ceramic media



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?

Beautiful polished semi precious stones from our rotary tumbler

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