How to Tumble Agates
Agates are stones that usually have a dull, rough outer surface. By tumbling them in a rock tumbler, their inner beauty can be revealed. A rock tumbler uses a series of coarse to fine grit and polishing powders to remove the dull outer coating and bring out the internal luster of agates. The tumbling process generally takes 4 to 5 weeks to polish the rough agates to a high degree of shine.
Things You'll Need
- Rock tumbler
- Grit: coarse, medium, fine, polishing
- Water
- Pail
- Soap
- Scrub brush
Instructions
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1
Rinse any dirt off the surface of your rough agate stones so that the grit will be able to make full contact with the agate easily. Place the agate pieces in the rock tumbler barrel with a small amount of coarse grit according to the recommendations made by your tumbler's manufacturer. Fill with water to just above the level of your stones. Turn the tumbler on and allow it to run for one week or as otherwise recommended by the manufacturer.
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2
Remove your agates from the tumbler after one week. Pour the contents of your tumbler into a pail of water and separate the agates from the spent grit slurry, which should be discarded outside. Check to see that rough or sharp edges, pits and nicks are removed before changing to a finer grit. Put your agates through a second cycle of the same coarse grit if you are not satisfied with the overall shapes and smoothness at the end of the first cycle.
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3
Rinse all of the residue carefully from your agate stones and clean out the tumbler barrel thoroughly. Inspect crevices to be sure that all of the coarse grit slurry has been removed so that it will not scratch your agates during the next round of tumbling. Remove any stones that have broken into pieces smaller than your minimum desired size or 1/4 inch. Examine stones and if satisfied with the shapes and smoothness, place your stones once again into the tumbler, the recommended amount of medium coarseness grit and water to cover the stones. Turn on the tumbler and allow it to run for one more week or as recommended.
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4
Repeat the process of pouring out and rinsing your agates after this medium grit cycle. Remove any subsized stones or those that have broken and have sharp edges that will scratch your now smoothed and lightly polished agates. Give your agates and the tumbler barrel a thorough inspection and scrub the barrel with soap and water and rinse well to assure that you have removed all coarse grit that could scratch the stones if present during the polishing cycles.
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5
Place your agates into the tumbler barrel again and add the finer, polishing grit and water. Consult your manufacturer's instructions since some recommend that the water level be just below the level of the stones for this last cycle. Turn on the tumbler and allow it to run for 7 to 10 days. Check the status of your stones and if more polishing is required, rinse the spent slurry from the stones and barrel, add more polishing grit and repeat the polishing cycle again. Remove stones from the tumbler when they have reached the desired degree of polish. Wash, rinse and dry your tumbled agates and clean your tumbler well.
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Tips & Warnings
Follow manufacturer's recommendations regarding the weight capacity of your tumbler barrel and the exact amounts of grit to add (generally 1 to 3 teaspoons).
In order to work, the grit must have a higher rating on the Mohs scale of hardness than the stones you are tumbling. If there are areas of differing hardness in your stones, softer areas will abrade differently than the harder areas.
Avoid mixing batches of stones of different hardness to get the best results with the least amount of tumbling time.
Never pour grit slurry into sink drains, as it can harden and severely clog the drain. It will also harden into a cement-like cake if left to sit in your tumbler barrel. Discard outside in a place where the fine grit can be rinsed into the soil.
Use proper caution when using water around electrical appliances such as your rock tumbler.
References
Resources
- Photo Credit agate image by Hubert from Fotolia.com
