How to Use a Rock Tumbler: Step-by-Step Guide
Loading, grit stages, water level, run times and cleanup: everything you need to know to run your first batch.
1. Choose your rocks
Tumble stones of similar hardness together. Harder stones such as agate, jasper and quartz take a good polish, while soft stones tend to wear away or scratch. Mixing sizes helps the stones cushion each other, so use a range of small and medium pieces.
2. Load the barrel
Fill the barrel about half to two-thirds full of rock. Too empty and the stones fall instead of grinding against each other; too full and they cannot move freely. Add the amount of grit recommended for your barrel size.
3. Add water
Add water until it just reaches the top of the rocks. Too little water leaves a thick paste, while too much dilutes the grit and slows the work. Wipe the barrel rim clean so the lid seals.
4. Run each stage
Run the tumbler continuously through each stage, using a finer grit each time. A typical run goes through coarse grind, medium grind, pre-polish and polish. Our tumbling timeline shows how long each stage usually takes, and the grit guide explains what each one does.
5. Clean between stages
Wash the stones and the barrel thoroughly before adding the next grit. Even a little leftover coarse grit will scratch the polish stage. Do not pour used grit slurry down a drain, because it can settle and clog pipes; let it settle and dispose of it in the trash.
6. Check the barrel
Look at the barrel after the first day or two. Some rough material can build up gas pressure in a sealed barrel, so open lids carefully and follow your tumbler manual's advice.
7. Polish and finish
In the final stage, add polish and consider plastic pellets or other tumbling media to cushion the stones. When they are finished, rinse well and dry.
What you need
A rotary tumbler such as the Lortone 3A or the Covington Single Gallon, plus grit and polish. A starter grit and polish kit covers the stages, and you can find more in our rock tumbler grit and polish collection. New to tumbling? Read Choosing Your First Rotary Tumbler.