How To Use A Rock Tumbler

A beginners guide to rock tumbling for rock collectors.

how to use a rock tumbler

How To Use A Rock Tumbler

Have you ever looked at someone else’s rock collection and wondered how in the world they got such beautiful looking gemstones?  Believe it or not, you can also make your rocks look just as good!  In this article, I’m going to explain exactly how to use a rock tumbler to elevate your rock collection to the next level!

The Rock Tumbling Hobby

Rock tumbling, or rock polishing, is an incredibly fun hobby for children and adults alike It gets you outdoors, keeps you active and is a relatively inexpensive hobby to get into.  In addition, the stones you walk away with at the end of a tumbling session are so beautiful and different than what you started out with. Often times you never would have imagined that dull looking rock could be so beautiful!

The first time I saw a rock tumbler in action was when I was about 9 years old.  Ever since, I have been intrigued by the idea that we can turn ordinary looking stones into beautiful gemstones.

The Rock Tumbler

A rock tumbler is a fairly simple machine which has the sole purpose of taking ordinary looking rocks, turning them over and over in a mixture of grit (sand) and water and polishing them into smooth, round, brilliant stones.

The tumbling machine has a barrel which is connected to a motor.  The motor is what keeps the barrel constantly moving. Inside the barrel is where the grit, water and stones are.  As the barrel moves, the grit slowly wears away the sharp edges on the rocks, eventually shaping them and polishing them. This is the exact same process that wears away rocks in nature, just on a much faster track!

Single Barrel Rock Polishing Tumbler and Geology Kit

how to use a rock tumbler

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There are two different types of tumblers available. Rotary tumblers and vibratory tumblers.  The most common type, especially with beginners to the hobby, are rotary tumblers.These are the ones you may have seen, with the barrel that turns around and around.  Rotary tumblers will not only smooth and polish your rocks, but they also make your rocks round, changing the overall shape of the rock.

Quick-n-EZ Vibratory Rock Tumbler

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Vibratory tumblers are a little more advanced, and are generally used to polish rocks that have already been tumbled.  The advantage of vibratory tumblers is that they are much faster at polishing your rocks than rotary tumblers are.  Many people will even have both kinds of tumblers on hand.  First they shape their rocks in the rotary tumbler then transition to the vibratory tumbler to smooth and polish.  Doing this can decrease the time it takes to shape and polish your rocks by almost 66%!

Where to find rocks for tumbling

Rocks for tumbling can be found virtually anywhere. Take a walk around your neighborhood, or a hike through the woods. Always be on the look out for spots that may reveal special kinds of rocks.  These areas might be riverbeds, streams and beaches where erosion has occurred.

Other locations to consider for where to find rocks for tumbling are quarries, construction sites and roadside ditches.


Rough Rocks In Bulk For Tumbling

If you don’t live in an area where rocks for tumbling aren’t easily accessible, not to worry. You can get your rough or raw rocks for tumbling without ever stepping foot outside!  With the click of a mouse you can have delivered to your doorstep bulk rocks for tumbling.

If looking for a source of high quality rough rocks to use in your rock tumbler, you may find my recent post, Rough Rocks For Tumbling And Raw Gemstones For Polishing useful.

Fantasia Mining 3 lbs Bulk Rough Madagascar Stone Mix with 30 Page Stone Info Book

I like this mix of rough rocks because included with the rocks is a 30 page identification booklet.  In addition to being able to identify the many different types of stones you’ll receive, it also gives information about each type of stone.

how to use a rock tumbler
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How To Use A Rock Tumbler

Rock tumbling is done in four different stages. Please note, that a thorough cleaning of the barrel is absolutely necessary between each stage.  You want to remove ALL of the grit from the barrel and the rocks before moving on to the next stage.

Stage 1: Shaping (60/90 grit)

The first step in tumbling is to shape with coarse grit.  What this does is knock down all of the rough and sharp edges from the rocks.  This stage also reshapes your rocks into a more round looking stone.

For this stage you want to fill the barrel about half or a little over halfway full of rocks.  Then you’ll add the coarse grit to the barrel.  You want to read the manufacturer’s instructions for your tumbler, but a good rule of thumb is about two tablespoons of coarse grit per pound of rocks.  So be sure to weigh your rocks first!

You can add plastic tumbling pellets to the barrel in this stage if you want, but it is not necessary unless you don’t have enough rocks to fill your barrel.

Finally, fill your barrel with just enough water to cover the rocks. Close the lid.  Attach the barrel and turn your rock tumbler on!

Please note, that if you’ve never used a rock tumbler, they are typically pretty loud.  So think about finding a place in the garage or out in the shop where you can let your tumbler do its thing and not be too disruptive.

In about a week, check on the progress of your rocks.  Are they changing shape?  If so, then it’s time to move onto step 2 of the tumbling process.

Stage 2: Medium/Fine Grit (120/220 grit)

After thoroughly cleaning out all of the coarse grit out of the barrel and rinsing off all of the rocks, repeat the same process as before.  Except this time you will use medium/fine grit and plastic tumbling pellets to help protect the rocks from hitting each other.  This stage of the process will remove any scratches, cracks or dimples that might be visible on the rock.

I tend to keep a closer eye on the rocks during this stage. I like to take a peek at them every other day.

Stage 3: Pre-Polish (500 grit)

After another thorough cleaning, you’re ready for stage 3. Same process as before.  This stage also takes about a week.  Again, I like to keep an eye on things by taking a look every other day or so.

Stage 4: Polishing

After your final barrel cleaning, you’re finally ready for the polishing stage!  If you haven’t used plastic pellets in the previous stages, please use them now.  In this stage you MUST use plastic tumbling pellets to prevent your rocks from hitting against each other and ruining all of the hard work you’ve put in so far.

After a week or so in this stage, your rocks should come out looking brilliant and beautiful.

how to use a rock tumbler to polish rocks
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Now that you know how to use a rock tumbler, it’s time to get out there and start collecting rocks to tumble!

Are you new to the rock tumbling hobby?  If so, leave a comment below and tell us how you got into it and what kind of rocks you’re currently tumbling.

Happy tumbling!