Step 3 of the process
Pre-polish
The stones should look smooth and slightly satin when dry. If they do not, polish will not save them.
- Goes in the barrel
- fine grit, 500 or 600 silicon carbide
- Typical run, rotary
- about 7 days
Step 3 is the fine grit, usually 500 or 600 silicon carbide. Some kits use a 1000 grit aluminum oxide instead. This is the step that decides whether the polish works: it leaves a surface so fine that polish only has to brighten it.
Wash everything again, load as before and run for about 7 days. Many dull batches trace back to this step being cut short, so give it the full week.
Check the stones dry, not wet. Water hides scratches. A stone that looks satin and feels silky when dry is ready. One that still looks chalky or shows lines goes back for another run.
Ready to move on when: Dry stones look satin and feel silky, with a faint glow on the best ones.
Common mistakes at this stage
- Judging the stones while they are wet.
- Cutting the run short to get to the polish.
Gear for this stage
Useful at every step
- How much grit to use in a rock tumblerHow much grit, rock and water for your barrel, with run times for every step.Tool
- Rock tumbling grit chart: grit size, amount and time for each stageRock tumbling grit chart for all four steps: grit size, what each step does, days per step and how to tell it is done, plus about 2 tbsp of grit per pound.Chart
- How long to tumble rocks: time for each stage and the full runHow long rock tumbling takes: about 7 days per stage and 4 to 6 weeks for a full batch, with times by rock type and the signs that a stage is finished.How-to
- How to tumble rocks: a step-by-step guide for beginnersHow to tumble rocks in a rotary tumbler: load the barrel 2/3 full, run four grit steps of about 7 days each and clean between them. 4 to 6 weeks in total.How-to