Are you thinking about using a rock tumbler? Do you want to create beautifully polished rocks in a multitude of colors? Rock tumbling is a cool and fun hobby that promotes learning of geology. Despite how cool it is to open tumblers and view all the polished stones however, you should know that this is not a quick and easy process.
How Long Does Rock Tumbling Take?
The length of time that it takes to tumble rocks in a rock tumbler can vary depending on the size and type of rocks being tumbled, as well as the type of tumbling media and the desired level of polish. In general, the tumbling process can take anywhere from several days to several weeks.
For example, small, smooth rocks may only take a few days to polish, while larger, rough rocks may take several weeks to achieve a high level of polish. It is important to carefully follow the instructions for your rock tumbler in order to achieve the best results.
If you’re thinking about buying a rock tumbler as a hobby, here’s what you need to know:
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Types of Rocks Suitable for Tumbling
Certain rocks are particularly well-suited for tumbling due to their hardness and ability to achieve a polished finish. Rocks like agate, jasper, and quartz are popular choices among enthusiasts. These stones have the necessary durability and surface properties that allow them to polish beautifully, revealing brilliant colors and patterns. Beginners might want to start with these gems to maximize their chances of success.
Beyond agate, jasper, and quartz, rocks such as petrified wood, tiger’s eye, and aventurine are also excellent for tumbling. These stones not only polish well due to their hardness but also reveal spectacular natural designs and colors that make them appealing to collectors and jewelers. Starting with a variety of suitable rocks allows hobbyists to explore different outcomes and find which stones they enjoy working with most.
There Are Actually Two Types of Tumblers
First off, you should know that there are two types of tumblers in the market today. The first one is the rotary tumbler and is the most common one in the market today.
As the name suggests, this rotary tumbler works through continuous rotation of the barrel. The rocks inside smash against each other, polishing the surface and allowing the smooth color to come out.
The second version is called the vibratory tumbler which just shakes and vibrates to promote friction for polishing. Of these two, the rotary tumbler usually takes longer to produce the smoothened stones because of the different stages you need to go through as well as the various grit types that need to be used.
Of course, it’s perfectly possible to use both types, one after the other, in order to speed up the process.
Factors Affecting Tumbling Time of Stone
Type of Tumbler
Rotary tumblers usually take a total of 4 weeks to produce the polished stones. The first stage takes seven days and using the heaviest or coarse grind followed by another seven days of medium grind. The third week is a fine grind until eventually, you get to the final polishing stage.
With each stage, you throw out the garbage, put in a new grit material and allow the barrel to do its job without disturbing the contents. Some enthusiasts would sometimes extend the process by repeating a grind, especially if they’re not happy with what they got.
A vibratory tumbler however manages to cut that time cleanly in half. You also skip the coarse grit and go directly to a medium grit for 24 hours or until you’re happy with how the rocks look. You then follow this up with the fine grit and then the polishing grit for 3 days each. Check and repeat as needed.
What if you use both the rotary and vibratory tumbler to speed up the process? Indeed, this will speed up the stages further without reducing the quality of the stone you come up with. The rotary tumbler would be used with a coarse grind for 7 days before moving it to the vibratory tumbler.
The vibratory tumbler would be responsible for the medium, fine, and polishing grit, all three taking one week or less. This will produce beautifully polished stones that would look better than the stones you get if you only use a vibratory tumbler type.
Regularly checking each stage and maintaining the right amount of grit is also important. Always ensure the grit particles are not too coarse for the final stages, as this can hinder the polishing process. Some enthusiasts recommend using ceramic media as a buffering agent to prevent chipping and enhance the polishing effect. This technique can refine your results, especially when handling delicate stones.
So why not just use the vibratory tumbler to really get fast results? There are two main reasons for this. The first one is that a vibratory tumbler is much more expensive. It costs more than 50 percent of the rotary tumbler which can be off-putting for complete beginners.
The second reason is that vibratory tumblers do not create rounded stones. It smoothens out the surface, but if you want a softly rounded look, the vibrator type would not be a good choice.
Hardness of the Rock
The hardness of the rock will also determine how long it would stay in the tumbler for you to produce a smooth finish. Harder rocks like quartz, agate, and jasper may need all of four weeks or more inside a rotary tumbler.
The likes of marble, fluorite, and calcite however, are integrally softer may need only a short period of time inside the rotary.
As a rule of thumb, anything with a hardness of 3 in the Mohs scale would need only 3 days to smoothen out. For those that are between 4 to 5.5 in the scale, 4 to 5 days of rounding would be perfect. Anything beyond that however would need the full 7 days to create the rounded curves.
Note however that when we talk about rounding rocks based on their hardness, we are only referring to the course grind. Hence, a stone with a hardness of 3 only need to be on the coarse grind for 3 days.
After that, you can follow up with the medium grind, the fine grind, and the polishing grind – all for the requisite period of 7 days each.
If you’re picking up stones from the wild and not sure where it places in the hardness scale, try using common objects as a reference. For example, a fingernail has a hardness of 2.5 so if you can scratch the stone with your fingernail, that means that it is softer than your nail.
A copper penny is 3.5, a knife is 5.5, an ordinary steel nail is 6.5, and a drill bit us 8.5. Have these small things handy when checking stones and you should be able to tell which stones will take longer to tumble.
Understand that when rock tumbling, the rocks should be the same level of hardness, otherwise they might scratch each other inside the barrel. If this happens, you’ll ruin the end result of the rocks which can be disappointing.
Sizing of the Rocks and the Tumbler
Remember that the polishing action comes primarily from the friction you get between the rocks and grit you put inside. If the rocks are too big in relation to the barrel, it would take a longer time to finish it completely.
The same is true if you load the tumbler with too many rocks. You’d think that when loaded with rocks, there would be more “friction”, but that’s not the case at all. You want there to be enough space in between for the sanded part to float in.
So how big should the rock be? Ideally, it should not be more than 50 percent of the diameter of the barrel. This guarantees that there’s enough tumbling space in there to create friction.
As for the volume of the barrel, make sure to fill it only up to ¾ with rocks. Put in just enough water to fill the spaces between the rocks, making sure that it doesn’t go above the topmost portion. Finally, add in the grit, lock the tumbler and allow it to work.
The Integrity of the Rocks
When we say “integrity” of the rock, we’re talking about the likelihood of it fracturing in the middle of the stage. Even before putting the rocks inside the rotary tumbler, you should make sure that the rock itself looks solid with zero chances of breaking up inside the barrel.
Environmental Considerations in Rock Tumbling
It’s helpful to consider the environmental impact of rock tumbling practices. The process requires water for movement and rinsing, so be mindful of the amount used. Recycling water whenever possible can reduce waste. Also, disposing of used grit responsibly is necessary, as it contains residual stone particles. Many hobbyists recommend allowing the grit to settle in a separate container before safely discarding it. These eco-friendly practices ensure both effectiveness in tumbling and consideration for the environment.
Checking in Between Intervals
Keep in mind that checking the stones between each step is important if you don’t want to accidentally lengthen the smoothing out process. Check for fractured and pitted stones which look like they could break up when allowed to go through the tumbling process.
This is because these small portions can break off and ruin the other stones – especially if you’re already using a medium, fine, or polishing grit. Pitted stones can also capture the smaller grit particles and therefore prevent them from rotating and polishing the area.
With each tumble, do a thorough inspection and discard the stones that will not give you the results you want. Otherwise, you might have to repeat the process which will take longer.
To decide if rocks are ready to move to the next tumbling stage, examine them closely for surface smoothness and absence of sharp edges. Rocks should have an even texture, indicating that the current grit has done its job.
A simple rub test with a finger can reveal areas that still feel rough and need additional time in the current stage. A little patience at this step ensures the rocks achieve their best potential polish.
Can You Skip Stages?
Some enthusiasts want to see results quickly so they choose to skip certain stages or perhaps try to extend one stage and skip another. For example, there are those who would go directly to polishing grit after using medium grit, therefore bypassing the fine grit.u003cbru003eUnderstand that while this possible, the results may not always be as expected. There’s a reason why there’s a process for rock tumbling that has to be followed – even by serious enthusiasts. Each grit type has a particular purpose and by skipping one in favor of another, you might scratch the surface and produce unpolished stones no better than the ones you find on the road.u003cbru003eOf course, some enthusiasts will tell you that it’s possible to skip steps with certain stones. However, this is a trial-and-error technique that allows you to learn as you go. After some time with rock tumbling, you should be able to judge what to do next with the rock you got and thereby shorten the tumbling time as you understand the nature of the rock and the grits used.
Vibratory tumbler vs rotary ? Is there a difference?
The main difference between these two types of tumblers is the way in which they tumble the rocks. A vibratory tumbler uses a vibrating motion to agitate the rocks and abrasive grit inside the tumbling chamber, while a rotary tumbler uses a rotating motion to tumble the rocks.
What is stone or rock tumbler grit used for?
Stone or rock tumbler grit is a abrasive material that is used in a rock tumbler to smooth and polish rough rocks and stones. The grit is made up of tiny particles of hard, abrasive materials, such as silicon carbide or aluminum oxide, which act as a cutting agent to remove small amounts of material from the surface of the rock. As the rocks and grit are tumbled together in the tumbling chamber, the grit gradually wears away the rough edges and smoothes the surface of the rock, resulting in a polished finish.
Common Mistakes in Rock Tumbling
Beginners often make mistakes that can lead to suboptimal results in rock tumbling. Common issues include overloading the tumbler, which reduces the movement needed for polishing. Incorrect usage of grit, whether in size or amount, often leads to scratches or incomplete polishing.
Additionally, insufficient cleaning between stages can cause cross-contamination between grits, affecting surface quality. Paying attention to these details enhances the final polished product.
Conclusion
To wrap it up, there’s no fixed or perfect time for rock tumbling. No matter how excited you might be to open that barrel and find amazingly colored stones, the fact is that good results take time.
Hence, be patient and continue to learn about rock tumbling so that you can put your own spin on things and perhaps develop a technique that will let you get faster results without diminishing the quality of the polished rocks.
