| A rock tumbler is a simple machine used to polish rocks. Here's how most tumblers work..
Rough rocks are placed into a rubber barrel with water and tumbling grit. The machine then rotates the barrel,
tumbling the rocks and wearing them smooth. The rocks are cleaned up and then tumbled with a finer grit, then
with a pre-polish and finally with a rock polish. Tumbling rocks is easy and many people enjoy the hobby. |
|
The rocks on the left are known as "tumbler rough" - crushed rocks that have an ability to accept a polish. The rocks on the right are tumbled gemstones that have been through the tumble-polishing process. See how the finished rocks have been rounded and their surfaces are now polished? What an amazing transformation! Kids really enjoy watching the rocks transform from rough to polished stones. We still enjoy opening the barrel! Wow! |
| How Do Rock Tumblers Work? |
| If you visit a beach, the rocks that you find there are usually rounded rocks and pebbles. They are round because the sharp edges have been worn off as they were rolled around by waves crashing onto the beach. A similar process happens inside of a tumbler barrel. Rough rocks are rounded and worn smooth by the tumbling action. Teachers sometimes use a rock tumbler to teach a lesson on mechanical weathering. |
|
This photo shows about two pounds of rough rock ready for the tumbler along with the four ounces of grit that will serve as an abrasive. If you look closely at the tumbler barrel you will notice that it is not perfectly round inside. Instead it has numerous flat surfaces. As the tumbler barrel turns these flat areas prevent the rocks from sliding and encourages the gentle tumbling action needed to produce nicely rounded gemstones. |
| What Types of Rock Can Be Tumbled? |
| Most types of rocks do not tumble well. The best rocks for tumbling are solid, free from voids or cracks and have a very smooth texture (instead of being grainy). Agates, jaspers, quartz, feldspars and obsidian are examples of rocks that can be tumbled. |
|
This photo shows what the rough on the left looks like as finished gemstones. From the top and left to right.... obsidian, rose quartz, unakite, yellow quartz, amethyst, tiger eye, green quartz, blue quartz. Many other types of rocks and minerals can be tumbled. |
| Tumbling requires patience. Most steps in the tumbling process take about seven days in a rotary tumbler. Using a calendar or a tumbling log is a good idea unless you have the memory of an elephant! We write down all of the details in a tumbling log. That log can be a very useful reference when you tumble similar rocks in the future. |
|
Lots of people do tumbling on weekends. They start their tumbler on Saturday or Sunday and let it run all week. The standard four-step tumbling process will take about one month. It teaches patience! Some people run the coarse grind two or three times in a quest for perfectly-rounded rocks. See our article: "How Long Does Rock Tumbling Take?" |
| Most rotary tumblers have a rubber barrel for a reason - it reduces the noise. Also, keeping the tumbler properly oiled according to manufacturer's instructions will help keep it quiet. A small tumbler makes about as much noise as vigorously shaking a 1/2-gallon carton of orange juice. |
|
Place your tumbler in a part of your house where a little noise will not be a problem. Many people place them in their garage, basement or laundry room. We have always run our tumblers in the basement. For more information see our article: "How Much Noise Does a Tumbler Make?" |
| What Can I Do With Tumble-Polished Stones? |
| Lots of people make jewelry items with their tumbled stones. Some rock tumbler kits include items for jewelry-making. Keychains, earrings, tie-tacks and rings are the most common items made from tumbled stones. |
|
Tumble-polished stones have a lot of decorative uses. Some people place a few in with their potted plants, some make refrigerator magnets or place them in a bowl around a candle. A jar of tumbles looks great on a shelf. They make great gifts, too. |
| Which Tumbler Should I Purchase? |
| Single barrel tumblers are the most popular. They cost a little less than a two barrel and they are less expensive to operate (you need less rock and grit). |
|
Double barrel tumblers allow you to process twice as much rock and have rocks in two different steps of the tumbling proceess. We own two of these. |
| What Type of Maintenance Does A Tumbler Require? |
| We oil the bearings of our tumbler every time we start a new batch of rock. Just one drop on each bearing. Check the instructions that come with your tumbler to know exactly how to care for it. |
|
The most common repair that a tumbler needs is a worn out belt. It is very easy to replace and you can purchase a new belt for a small tumbler for about three dollars. |
| Where Can I Learn More About Rock Tumbling? |
| Where Can I Get More Rocks to Tumble? |
| Some people live where rocks suitable for tumbling can be found in streams, outcrops, or on the ground surface. If you live in one of those areas you are very lucky! Whereever you go collecting, be sure that you have landowner permission or are in an area where public collecting is allowed. |
|
The easiest place to find rocks suitable for tumbling is on the internet. We sell lots of tumble-ready rocks right here on this website. There is nothing wrong with buying rocks. We do it all of the time! It is a lot cheaper than traveling to a distant location to hunt rocks. But we know that would be a fun trip! |
|
|
| Tumbling Articles and Resources |
|
