How to Use a Vibrator for Polishing Rocks
There are two common types of rock polishers, rotating tumblers and vibrating tumblers. Rotating tumblers take four to five weeks and produce smooth, rounded rocks. Vibrating tumblers take only a week and a half to two weeks and produce highly polished rocks that retain much of their original geological shape. The tumbler uses sand-sized pieces of silicon carbide grit, which is much harder than common rocks, to grind the rocks smooth. Tumbling grit comes in different levels of coarseness and is available at any geological hobby shop.
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Things You'll Need
- Vibrating rock tumbler
- Various sized rocks, up to 1.5 inches in diameter
- Tumbling grit
- Water
- Soap flakes
Instructions
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The Initial Grind
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1
Fill the barrel of the tumbler 3/4 full with rocks. For every 4 lbs. of rock, add 3 tbsp. grit.
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2
Turn the tumbler on and begin adding water slowly until grit begins to cling to the stones. Do not overfill or grit will rinse away from the stones.
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3
Replace the tumbler lid. Check the tumbler at least twice a day for clumped buildup of grit and ground rock. Add water to thin it out.
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4
When you are satisfied with the shape and look of the rocks, usually after two to seven days, turn off the tumbler and thoroughly rinse grit from the rocks and bowl. Do not dispose of grit in a sink or drain.
Polish and Finish
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5
Return thoroughly rinsed rocks to the barrel. Follow the same steps as with the initial grind, except use half as much grit.
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6
After two to three days to pass then thoroughly rinse the rocks and barrel, removing all grit.
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7
Return the rinsed rocks to the barrel and repeat the steps for the initial grind, again using half as much grit as in the first grind.
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Rocks polished in a vibrating tumbler retain much of their natural shape. After two to three days remove and rinse the rocks and barrel once more. Return the rocks to the barrel with 1 tbsp. of soap flakes or detergent and run with water for a few hours for the final burnish.
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Tips & Warnings
Rock tumblers are noisy and must run constantly during the process. Make sure to set the tumbler up in as remote a location as you can. A garage is the ideal place. You can add steps to the polishing phase. Some enthusiasts like to use progressively finer grit with each step. As with sandpaper, the finer the grit the smoother the finish. The initial grind should always be done with coarse grit.
Never try to dampen the sound with any sort of cloth. It can burn out the motor and presents a fire hazard. You should take care to use rocks that are similar in hardness in each batch. Significantly harder rocks can damage or crack softer ones prepared in the same batch. Use rocks of similar roughness. Rocks taken off the ground are already partially eroded and will take less time to smooth than rocks you have broken with a hammer.
References
Resources
- Photo Credit rock collection image by Andrew Kazmierski from Fotolia.com rock art 49. image by mdb from Fotolia.com
