It’s all a matter of observation. A typical rotary batch takes about four weeks from rough rock to polished stone, but every load is different. The stones, the barrel and how full you run it all change the timing. Here’s what to expect, and how to keep track so you know when to move on.
Typical times
- Rotary tumbler: about 7 days for each of the four steps (coarse, medium/fine, pre-polish and polish), so about 4 weeks in total. The coarse step often needs a second week.
- Vibratory tumbler: 1 to 3 days per step, so about 1 to 2 weeks for already-shaped stones.
- Soft or fragile stones: run gentler and shorter, with more filler in the barrel, and check more often.
How often to check
Set a routine based on what you are tumbling and which machine you use.
- Rotary, first day: open the barrel after 24 hours to check for leaks and gas buildup. During the coarse step, vent it every day or two.
- Rotary, after that: check every few days. Look at the slurry, listen for a steady tumble, and make sure the barrel is still turning.
- Vibratory: check two or three times a day, and add a little water when the slurry thickens or the load slows down.
Keep a tumbling log
A simple notebook turns every batch into a lesson for the next one. Over time it becomes your own record of what works for your rocks and your tumbler. For each batch, note:
- the stones in the load and roughly how much they weigh;
- the grit, the amount, and the date each step started;
- what you saw at each check, such as slurry thickness, gas, leaks or noise;
- how the stones looked, dry, at the end of each step, and whether you repeated it.
Let the stones decide
The calendar is only a guide. Before moving to the next grit, rinse a few stones, let them dry completely and check them in good light. Read how to tell when a tumbling step is done for what each stage should look like, and see our grit stages guide for run times by stage.