It takes years and years for nature and its elements—dirt, rock, water, and sand—to smooth a rock's surface. But a rock tumbler can get you those same results in considerably less time. A tumbler rolls or vibrates the rock over and over until the sharp edges and dull exterior are worn away, revealing a smooth, shiny surface. Use a variety of rock sizes for best results. Small rocks are good for getting inside the nooks and crannies of larger rocks.
A barrel that's too full won't allow enough room for the rocks to go down. A barrel that isn't full enough won't allow the rocks to "climb" the wall. Whether using a rotary rock tumbler or vibrating rock tumbler, getting those pretty pebbles is a 4-step process: Step 1 rounds the rock. Step 2 removes deep scratches from the rock. Step 3 removes fine scratches. Finally, step 4 adds a glossy shine.
1. Selecting the size of the rock tumbler you need is pretty simple and follows what common sense would tell you. For stones smaller than 1 inch in diameter, you can go as small as a 3 pound rock tumbler. Six pound and 12 pound barrels can handle stones up to 2.5 inches.
2. Rock tumblers that accommodate only around 1.5 pounds should be reserved for small, coin-sized stones. These size restrictions are important because, for a good polish, it is necessary to keep the tumbler about half full.
3. If you want to eliminate the risk of jeopardizing your rock polish in the last stage or you want to expedite the process, a second tumbling barrel is a great choice for getting this done.
4. Of course, purchasing a two-barrel tumbler is a bit more expensive. This is naturally cheaper than buying a second machine, and you get a lot more rocks at a quicker pace.
5. The question of vibrating vs. rotary rock tumblers is one you're bound to be faced with. Essentially, they both produce a good polish, but rotary models are easier to operate and make a more smoothed, rounded polish.
6. The specific purpose of vibrating rock tumblers is that they keep the shape of the stone constant while rotary rock tumblers will drastically round them out. Therefore, if you go to a lot of trouble to shape your rocks prior to polishing, a vibrating tumbler would be best.
7. An additional feature of the vibrating tumbler is that they finish in 7 to 10 days, compared to the month to 45 days required by a rotary rock tumbler.
8. The advantage of rotary rock tumblers is their ease of use and price relative to the vibratory models. Rotary tumblers can, at times, be almost half of the price of a similar-sized vibratory tumbler.
9. Rotary rock tumblers, because of their more kinetic activity and need for more polish, are not recommended for fragile rocks. They are also occasionally prone to leaks.
10. Plenty of rock books are available about rock polishing and tumbling for hobbyists and professional jewelers.
