Rock Tumbler Polish & Grit

Grit Is a Sequence, Not a Product

Tumbling stone to a shine is a multi-stage process. A coarse grit does the shaping and grinds off the rough surface, a medium grit erases the scratches the coarse stage left, a fine or pre-polish grit refines the surface further, and the polish stage brings up the shine. Each stage typically runs for days in a rotary barrel, and the grit particles fracture and dull as they work, which is why grit is bought by the bag and not once. Skipping a stage rarely saves time; the polish just spends its whole run trying to erase scratches it cannot reach.

Keep the Stages Clean

The whole system depends on separation. A few stray particles of coarse grit riding into the polish stage will scratch an entire load in its final hours, so rinse the stones and the barrel thoroughly between stages and never pour used slurry back over a batch. Many tumbler owners keep a dedicated barrel or bowl for the polish stage alone. Match the grit quantity to the media and load size your machine calls for, and let each stage run its full time; this process rewards patience more than any other variable.

Coins, Stones, and the Rest of the Setup

Rockhounds run the full grit sequence on stones. Detectorists usually come at tumbling from the other side, cleaning a season of dug coins, and that job leans on tumbling media and finishing compound more than on a four-stage grit run; both live on the tumbler parts and media page along with bowls and replacement hardware. The machines themselves, and the rest of the find-cleaning lineup, are under all tumblers and cleaning, including the classic rotary line on the Thumler's Tumbler page.