Rock Tumbling is a technique used to smooth and polish the rough surfaces of small rocks to make them beautiful and attractive so that they can be used in jewelry and other decorative functions in homes. Rock tumbling works on the same principle as barreling in metal work. Its main goal is to make rocks smooth and bring out their natural beauty.
If you have ever picked up a smooth and perfectly rounded rock on a river bed or on the beach then you have seen what tumbling does to rocks. Such smooth rocks are usually tumbled by the river waters for hundreds of years to achieve such smoothness. But, the same can be done at home in a couple of weeks using the right equipment.
Rock tumbling is mainly a hobby for people who love to collect different rocks and then use them for making decorations, crafts, jewelry, etc. It is a simple hobby for a lot of people and can be enjoyed by the whole family.
All you need to start is some basic equipment to get started, and some rocks of course!
A Brief History of the Rock Tumbler
While naturally tumbled rocks have been collected from rivers for thousands of years, the modern rock tumbling has only been existence for around a half a century. The first rock tumbling machines were built in the 1950s giving rise to the hobby. The machines were meant to cut and make smooth rough rocks from nature so that they can be used in jewelry. Before that, people relied on rivers and waterways to collect beautifully smooth rocks for use in home decorations and in jewelry.
With the invention of tumbling machines, rock tumbling quickly became a popular activity first with small gemstone and jewelry companies which begun manufacturing tumblers. Back then tumbler barrels were made out of old paint cans before plastics and rubber materials were adapted.
In the 1960s there were several dozen companies manufacturing tumblers. Most of these firms either collapsed or changed their focus from the tumblers. Today only a few remain that build quality tumblers. Most of the tumblers in use are by hobbyists using small machines in their own homes.
Why Tumble Rocks?
Rock tumbling is not just a hobby. Some people are commercially tumbling rocks to sell at gem shows and other similar venues.
Some of the fun uses of tumbler rocks that could get you rock tumbling include:
Tools and Equipment you need to start Rock Tumbling
To start rocks tumbling you need a number of tools, equipment, and materials. Due to the growth of the hobby, all these can easily be found online. Some of the best tumbling tools and equipment you should use include:
1. The Rock Tumbler
This is a simple machine used to tumble rough rocks. It turns a barrel full of rocks, grit, and water round and round for a number of weeks until the rocks are smooth and polished. The machine comes with a barrel that you fill with the rocks you want to tumble.
You also add grit and water to the barrel. Grit is used as sand paper for cutting and smoothing out the rocks while water act as a lubricant for the process.
Currently, there are two general types of rock tumblers in the market: the Rotary tumbler and the Vibratory tumbler. The rotary tumblers are the most common tumblers in the market. This is because they are designed to shape rocks by knocking off edges and smoothening out your rough rocks. In fact, most people only know of the rotary tumblers.
Vibratory tumblers are far much less common. They are mainly used for polishing rocks already worked on by rotary tumblers. Because of this, they are only used by people who want to produce professional grade tumblers. If you don’t want to change the shape of your rocks but just polish them then this is the type of tumblers that you should use. The main advantage of the vibratory tumbler is that it speeds up the process of rock tumbling.
If you are just starting out then the rotary rock tumblers will do just fine.
Other than the machine for tumbling you need supplies to be able to tumble your rocks. The important supplies include:
Grit is the course materials that rub against your rocks during tumbling cutting the rough edges and shaping them to produce the desired outcome. Grits come in four primary courseness levels:
Grit is made from different materials and in different forms for different tumbling machines. It is, therefore, important you read the user manuals of your tumbling machines so that you buy the right grit for it.
b) Plastic pellets
Other than grit you may also need plastic pellets. When you don’t have sufficient rocks for the size of your barrel you will need to fill it with these plastic pellets so that you can tumble your rocks.
Without the pellets, you will have to wait much longer for you to get enough rocks. Even if you have enough rocks, during tumbling the process cuts them reducing their size. You will discover that your rocks cannot fill the barrel of your rock tumbler for polishing. Here the plastic pellets come in handy to take up the extra space in the barrel for you to do the polishing of your rocks.
Other than taking up empty space, plastic pellets help absorb the excess impact of rocks on your rock tumbler and speed up the process by countering the sliding effects of smooth stones. The plastic pellets are reusable and thus you don’t need to buy a lot of them. It is important to note that they are only for use in rotary rock tumblers.
If you are a serious rock tumbler then you may want to consider advanced tools such as:
You also need rock collecting tools if you plan on collecting your own rocks, but some of the best rocks for tumbling can be found easily be searching along river banks and gravel bars.
Where to Get the Right Rocks for Tumbling
Although a number of people prefer to buy rocks for tumbling it is really rewarding to find your own rocks in nature. Finding rocks is a very rewarding hobby that gets you way from the busy city life. It’s good exercise and adds a lot to the experience by finding your own rocks.
Quality rocks for tumbling are hard, nonporous with no cracks. Most quartz rocks such as jasper and agate fall in this category. These rocks are found in areas with a history of volcanic activities, along waterways and on ocean and lake beaches.
In the United States, the agate is the most popular rock for rock tumbling. This is because the rock is easily available and has great features such as being translucent with many beautiful patterns. Agate is mainly found in the western part of the United States particularly in states like Michigan, Arizona, Wyoming, Montana, California, Oregon and South Dakota.
Jasper is another common form of quartz used in rock tumbling. It is also common in western states such as California, Idaho, Utah, Arizona, Texas, Washington, Oregon, and Arkansas among others.
Other than the above two examples, quality rocks are found in different places across the United States and the world over. All you need to know where to find the right rocks in your locality is to buy a local rocks guidebook. Study various rocks and choose the once you think will give you the best results.
The Rock Tumbling Process
Rock tumbling is a relatively simple process, but it does involve a number of steps and stages. It is important that you go through and every stage to ensure that you get the best results. Here are the steps for the rock tumbling process:
1. Inspecting Your Rough
Whether you buy your rocks or you collect them from nature, the first important step in rock tumbling is to inspect your rocks. Remember starting with quality rocks results in high-quality finished stones. Examine the rocks you have carefully and discard any poor quality rocks that you may have.
Start by checking for porous rocks. Remove and discard such pieces. Sometimes, a large solid rock may have some porous pieces attached to them. Clean such pieces and remove all the porous parts for a better tumbling.
Next check for signs of fracture in your rocks so that you can deal with such pieces. Usually, fractured rocks will break into pieces during tumbling and this will not only produce poorly tumbled stones but will also scratch your other rocks in the same batch and thus lower their quality too. Discard fractured small rocks.
Also, sort your rocks depending on their level of softness. If you have different types of rocks it is important that you only tumble those with the same general hardness together. Tumbling both hard and relatively soft rock together will result in the softer rocks wearing out faster than the hard rocks and you may even completely grind away the softer rocks before the harder rocks are finished.
Finally, check the size of your rocks. If all your rocks are small and of relatively the same size then you don’t have to worry about the size. However, if you have both large and small rocks then size if great importance to you. You need to have small rocks in between the large rocks during tumbling so that the large rocks can be shaped evenly. Make sure that you fill the barrel with both large and small rocks to allow for smooth tumbling.
2. Loading the Tumbler Barrel
This is another important step that you need to pay attention to. First, make sure that the barrel is perfectly clean for loading. Check and remove any grit or piece of rocks from the previous tumbling. The rim and the lid of the barrel should also clean free from any form of particles that might cause leakages.
Once the barrel is clean, add rocks of the right sizes to about two-thirds of the barrel. In case you don’t have enough rocks to fill 2/3 of the barrel use artificial materials such as plastic pellets. This is important because if there is too much space in the barrel the rocks will be tossed around and can bruise the barrel. Add grit and water and start tumbling.
3. Coarse Grinding
This is the first step of the actual tumbling. Before you start the process make sure the barrel is 2/3 full with rough rocks. Add about two tablespoons level course grit for every pound of rock in the barrel and then add water to just cover the rocks. Now seal your barrel and run the tumbling machine for seven days.
After seven days, switch off the machine and open the barrel. You will discover your rocks covered in muddy water. Empty and wash the barrel. Also, put the rocks in a backed and wash them to reveal beautifully tumbled rocks. Make sure you rinse the rocks and remove all grits and tiny rock pieces before you move to the next step.
Remember to also inspect the rocks so that you discard those not suitable. Often a number of rocks will crack during tumbling and although they may appear to be well tumbled the crack may lower their quality. Also, check for rocks that still require further grinding so that you can take them through the process again. Often some rocks may not be ready for your intended use, return them through the course grinding process for another week until they are trimmed further.
4. Medium Grinding
After washing your rocks and inspecting them you can now move the next step with those ready for the process. Fill the barrel to about 2/3 with rocks. If you don’t have enough rocks you can use artificial materials such as plastic pallets.
Remember, you don’t have to go to this stage directly from the previous stage. If you have many rocks to begin with, then you should start by doing course grind for all of them first so that you can have more rocks for the subsequent steps of tumbling.
Once you have filled a clean barrel with clean rocks up to 2/3 full add two tablespoons level of medium grit for every pound of rock in the barrel. Add water so that the water line is on the top rock surface. Switch on your tumbling machine and tumble for another seven days.
After seven days switch off the machine and empty the barrel. Now clean the barrel and the rocks for the next stage. At this point, the tumbled rocks should have a smooth surface. Inspect your rocks to check those with cracks so that they can be discarded and those that needs to undergo the process again so that they are put in the right group of rocks.
5. Fine Grinding
This is the third stage of actual tumbling. Fill a clean barrel with clean rocks from the previous stage up to about 2/3 full. Add fine grit and water to the required levels. Run the tumbling machine for another seven days. At the end of the seventh day, stop the machine and open the barrel to reveal the rocks.
Empty the barrels and wash it thoroughly. Wash your rocks to remove the muddy substance and the remaining grit. Inspect the rocks and discard broken rocks and those with cracks. Also check the rocks to ensure that all are very smooth and have started having luster. Remove any rock that you think is not ready for polishing and add it to those undergoing the fine grinding process.
This the final step of rock tumbling. Fill a clean barrel with the smooth tumbled stones and add two levels of your favorite rock polish and then water to just below the rock level. Start the tumbling machine and run it for a week.
After one week stop the machines and remove your rocks from the barrel. This is the fun part! Admire your lovely stones.
If your tumbled rocks look hazy the consider burnishing them. This is a simple process of cleaning and shining your rocks by tumbling them for a few hours in water with detergent. To burnish your rocks, all you need is to place the rocks in your polishing barrel and then add water and a detergent of your choice. Tumble for a few hours then remove from the barrel and dry your tumbled stones.
It is important to take note of your detergent choice. Quite a number of people insist on using ivory bar soap or borax but you can use just about any detergent. The most important thing is that make sure that detergent you choose does not have additives that may harm your rocks.
Golden Rules for Successful Rock Tumbling
i. Don’t use sub-par stones
Often you will find rocks with problems such as cracked rocks or those with defects such as porous sections. All such rocks are not good candidates for tumbling and should be discarded. Tumbling such rocks will only result in disappointment as the cracks are likely to become bigger and the other defects more pronounced.
ii. Avoid contamination
Clean the barrel and its lid and the rocks before any tumbling process to ensure that there is no contamination. If more course grit or other dirt get into the next stage of tumbling then this will affect the quality of tumbled rocks you end up with. Dirt may also cause other problems such as leakages during tumbling.
iii. Be patient
It takes a lot of time to have the best results. You may be tempting to speed up the process by using shortcuts. This will only affect your results negatively. To get the best-tumbled stones be patient and do everything one step at a time.
iv. Keeping Records
For great results keep records. This will help you remember the kind of grits used last, the date you started tumbling, and the supply you have. Record keeping will make it easy for you to manage the process.
v. Mind the Noise
Tumbling machines can be quite noisy. Because of this, it is recommended that you keep it in the basement so that you don’t disturb your neighbors or even your partner who may shut it down before the process is completed.
vi. Maintain your Tumbling Machine
Your tumbling machine is expected to run for 24 hours every day for weeks. If it is not in top condition when you start, then it is likely to breakdown midway the tumbling. This will likely cause a lot of inconveniences to you. Follow the manufacturer’s instruction and keep your tumbler in top shape at all times.
It is worth mentioning that if you are serious about this hobby, you should invest in a quality tumbler. There are cheap plastic tumblers on the market sold for children. While these do work, they are poorly made and will generally wear out after a few loads of rocks are polished. Invest a bit more money into a quality tumbler and it will last you years.