how do rock polishers work

Do you enjoy pretty things and being in nature? If you answered yes, then you may consider starting a rock tumbling hobby. Tumbling rocks is something almost anyone can do. It doesn’t require a lot of work or a considerable upfront investment.

The key to rock tumbling is understanding the equipment you will use. Rock tumblers are relatively straightforward machines once you learn the basics of the hobby. So, how does a rock tumbler work? 

What Is a Rock Tumbler?

A rock tumbler is a machine that uses sand and water to polish and smooth rocks. It has a soft rubber barrel where you put the rocks, sand, and water. The tumbler has a motor that then turns the barrel to allow for friction to smooth out the stones. 

There are different types of rock tumbling machines that may work slightly differently, but the main goal is to use friction to smooth out the edges of the stones to create a beautiful finished product.

How Does a Rock Tumbler Work?

The most basic tumbler is a rotary tumbler, which has a barrel that turns around. This version is the most common option and is also the cheapest type of tumbler. 

If you want to know how to polish rocks with a tumbler, the operation is very simple:

  1. Put your supplies into the barrel. 
  2. Turn on the motor.
  3. The rocks tumble inside for one week at a time to become polished and smooth.

Using a rotary tumbler mimics the natural process of how rocks get smoothed out in nature.

As a beginner, rotary tumblers are probably the best rock tumblers for you to choose. They are easy to operate and won’t break the bank. You don’t want to invest too much in the hobby until you are sure it is something you will stick with, so a rotary tumbler is a good choice.

The other option is vibratory tumblers. With a vibratory tumbler, you will not actually tumble rocks. Instead, the machine uses vibrations to smooth the stones. You put your supplies in a bowl where they are rapidly shaken together to grind the rocks.

Vibratory tumblers are not as good at handling the smoothing process as rotary tumblers. A vibratory tumbler does best at polishing. You would probably need both a vibratory and rotary rock tumbler to get the tumbled stones in the shape you want them.  

polished rocks from a rock tumbler

What Are Rock Tumblers Used for and Why Use a Rock Tumbler?

Rock tumbling gained popularity because of the rise in people doing crafting as a side hustle. Tumbled rocks are helpful in a range of crafts, such as jewelry making or home décor. You’ll also find that people will buy them from you if you have gorgeous and varied rocks. 

The rounded shapes and shiny tumbled stones you get from tumbling are unique and allow you to create something of beauty that people will pay for.

Plus, people love rock tumbling because it is fun to create something from nature that others appreciate. Producing nicely rounded stones can give you a sense of calm and allow you a peaceful way to spend your free time.

If you love geology, then rock tumbling is an ideal hobby. You can explore nature and get to the hidden beauty beneath the rocks you find.

How to Use a Rock Tumbler

Using a tumbler machine is pretty easy once you learn the basic steps. You will also need to gather the proper supplies and find rocks you wish to polish. These steps are for the typical rotary tumbler since a vibratory tumbler cannot complete all the steps from raw to polished stone.

Step One: Coarse Grit Stage

The first step to tumbling is shaping the rocks. You will want to fill the barrel with:

  • Your stones 
  • Coarse grit 
  • Water 

It is essential to ensure the tumbling barrel is at least half full of rocks and that once you add the grit and water, it is 3/4 full.

You should weigh your rocks and add in two tablespoons of the coarse grit per pound. Also, when sealing the barrel, make sure it is clean of the rough grind, and the seal is tight, or water will go everywhere.

The goals of the coarse grit step are to get rid of the rough edges and get more rounded rocks. Do not expect polished stones at the end of this stage. Let your rocks tumble for about a week, and then check them. The tumbled stones should not have sharp edges. 

There should be no more rough rocks, and they should have a somewhat smooth surface. They will probably not be shiny rocks and may not be 100% smooth, but the tumbler should transform them from their original state.

Keep in mind: This coarse grind step is where the shaping of the rocks takes place. You will get the stones smooth in the next step. 

If you have specific shapes you want, you will need to pay attention closely as the form will not change much in the rest of the process. In addition, if you are using soft rocks, you will need to watch more carefully, as they will take shape much quicker than harder rocks.

Step Two: Medium Grit Stage

Before you can move to the next stage, you need to clean your rocks and clean the tumbler barrel. Make sure you get all the grit off the rocks and out of the tumbling machine.

This next step uses a medium grind grit. It just continues the first step by smoothing out the rocks. By the end of this stage, you will have the smoothness you desire. It will also slightly shape the stones, but no significant changes will happen.

The main goal with the medium grind tumbling process is producing nicely rounded stones. They should be free of:

  • Cracks 
  • Scratches 
  • Dimples
  • Other markings 

You should check the tumbled rocks every other day or more often during this stage.

Step Three: Fine Grit Stage

Again, before starting this step, make sure you completely clean your tumbling machine and the rocks. You will use a finer grit for this stage, which is also known as the pre-polish stage.

When you tumble tocks this time, the goal is to get them shiny. You will polish rocks in this step, where they take on the final look your wish to achieve. They should be nicely rounded before you reach this fine grind step because the fine grit grinding compound will not shape them at all.

It will take about a week for this stage to reach completion, so you can check them at that time. You will want to inspect them for a smooth finish before moving on to the next step.

Step Four: Polishing Stage

You have now reached the polishing stage. Be sure to clean the rocks and tumbler before moving forward.

This stage will bring out the luster of the rocks. It will help define colors and give you that shiny look you want in the final product.

Instead of the rough grit you used before, the polishing step requires plastic pellets. The rocks tumbling around need the cushion of these pellets, so they do not end up with damage. 

It is essential to fill up the space within the tumbling barrel. If you do not fill it with pellets, your rocks will suffer harm.

You will tumble polish the rocks for a couple of weeks. Keep checking on them. Look for damage and add more pellets or water as needed. You want stones with a good shine that have the final appearance you desire.

Step Five: Burnishing Stage

The last step is burnishing. Burnishing means adding the final element to keep the rocks looking good forever. You will not have to clean the barrel before this step.

Using polish liquid in the barrel instead of any tumbling grit or polish, you will add the rocks and some water. To this mix, add in a cup of powder washing detergent. Do not use liquid for this.

This step only requires a few days of tumbling. It will clean off the rocks and put a protective layer on them.

What Should I Put in the Rock Tumbler, and How Do I Choose Rocks to Tumble?

You can use all types of rocks in tumbling. Be aware that softer rocks will process much quicker than other rocks, so you should always separate your rocks before tumbling.  Check out our article on the best rocks for tumbling for more info.

Putting harder rocks with soft rocks will also damage the soft ones in rotary tumblers. The same applies when using a rough rock with smoother rocks. The type of rock doesn’t matter. You can tumble: 

  • Rough stones
  • Large stones
  • Angular stones
  • Uncut stones

Find rocks anywhere. You can visit rocky beaches or a local rock shop. You can also buy them online wherever you buy rock tumbling supplies.

How Long Does It Take to Tumble Rocks?

The amount of time rock tumbling takes from start to finish depends highly on the type of rock you are using. 

Vibratory tumbling generally takes less time than rotary tumbling because it doesn’t handle all the early stages of shaping and polishing. 

Generally, rotary tumblers take about three to ten days per stage to finish smoothing and polishing the rocks. Vibratory tumblers are similar but use fewer steps, so they take less time.

Wrapping Up

As a beginner to tumbling rocks, you should have everything you need to begin tumbling. Make sure to keep this guide handy so that you can refer back to it. 

Always read through the manufacturer’s instructions on your machine before you start, as well. The next step is starting on your new hobby and producing beautiful, smooth stones.

If you have any further questions, comment below, and I’ll try to help you out.

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