Stones found alongside rivers and oceans are generally smooth to the touch. That smoothness is attributable to the friction from the water and abrasion from sand and other stones. Polishing tumbled stones in a rock tumbler produces similar results depending on the type of stone and how long it has been tumbled. Stone polishing is a craft that has been practiced since the beginning of civilization, and remains popular among lapidaries and jewelry makers for both fun and profit.
Place the stones inside of the tumbler. Do not fill more than 2/3 of the tumbler with the stones.
Add enough water to just cover the stones.
Pour in approximately 4 tbsp. of coarse grit. Close the tumbler and check to be sure it is securely sealed before turning it on.
Allow the stones to tumble for approximately 5 to 7 days.
Pour the stones and grit out of the tumbler into a sieve and then rinse the stones thoroughly with clear water until they are entirely free of grit.
Place the stones back into the tumbler and repeat the process 2 to 3 more times replacing the coarse grit each time with a finer grit.
Place stones in the tumbler with enough water to cover but for the last tumble, pour in plastic pellets instead of grit. Run the tumbler for 5 to 7 days.
Examine the stones to see if they have been polished as desired.
Tips & Warnings
- Stone polishing is not an exact science. Depending on the type of stone, polishing time may need to be shortened or extended depending on the desired finish.
- Stone tumblers are available in several sizes. Choose the appropriate size that will allow the stones and grit to tumble freely.
- Rotary tumblers are more effective at both shaping and polishing. Vibrating tumblers are generally used for polishing only.
- A rotary tool with sanding and buffing accessories can be used to make minor adjustments to a stone, but the primary method is still a tumbler.
- When rinsing stones and grit, avoid pouring the grit into a household drain or toilet, as it is likely to cause a clog. Instead, discard grit in the trash after using. Do not reuse grit as it becomes less effective over time.
Things You'll Need:
- Rock polishing kit (containing silicon carbide grit and plastic pellets)
- Rotary tool with sanding and buffing accessories
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