When people think of rock tumbling they usually just think of the small toy tumblers they saw as kids, but rock tumblers can be much more varied and sophisticated than that. The biggest divide in the type of rock tumblers is between rotary and vibratory tumblers. I’ll dig into all of the differences between them and why you might choose one type over the other.
Rotary tumblers polish rocks by turning them in a cylindrical barrel, while vibratory tumblers shake the rocks in a bowl and take much less time. Both types of tumblers use varying sizes of grit to polish the rocks. Rotary tumblers produce more rounded finished rocks, while rocks in vibratory tumblers tend to hold their shape.
There are a lot of subtle but important factors that will determine which type of tumbler is the best choice for you. Both types have their pros and cons, and sometimes it’s even best to use them in conjunction with one another. The type of tumbler you choose at each stage of the rock tumbling process will have a significant impact on the finished product you produce as well as the time it takes to get there.
Tumbler Type Affects Rock Shape
One of the biggest reasons you might prefer a rotary tumbler over a vibratory tumbler (or vise versa) is the effect that choice has on the overall shape of the rocks at the end of the process.
A rotary tumbler will reshape angular and irregularly shaped rocks into well rounded, near-spheroidal specimens if left in the tumbler long enough. In contrast, vibratory tumblers will tend to retain the overall shape of the original rock, just smoothing the contours to a fine polish.
The reason a vibratory tumbler doesn’t change the original shape of the rock as much is due to the nature of the movement, all sides and surfaces of the rock are worked almost equally. In a rotary tumbler, the more prominent parts of each rock tend to get hit harder and more frequently, causing them to wear down and for the stone to become more rounded over time.
It’s worth noting that this reshaping happens almost entirely in step 1 of the tumbling process with the coarsest grit. This initial phase is enough time for rocks to lose most of their irregular shape, so in subsequent steps they won’t change nearly as much.
There is no ‘right’ decision here. Rounded or more naturally shaped stones are mostly a matter of personal preference but do keep in mind what you are planning to do with the rocks when you’re done. Personally, I like the variation and more natural look of rocks polished in a vibratory tumbler. I feel like it makes each stone a little more unique and adds character.
Vibratory Tumblers Take Less Time
This is, without a doubt, the biggest advantage that vibratory tumblers have over rotary models. You can crank through a batch of rocks in about half the time with a vibratory tumbler, so if you are the impatient type or need to be able to churn out a lot of material quickly then you will definitely want to invest in one.
Depending on the type of rocks you’re working with the time it takes to tumble the batch with a vibratory tumbler might be even less than half of what it would take with a rotary. This is in large part because you can skip the first step (coarse grit) you’d do with a rotary tumbler, but the subsequent steps all take less time as well.
| Grit Step | Vibratory Days | Rotary Days |
|---|---|---|
| Coarse | 0 | 14 |
| Medium | 7 | 10 |
| Fine | 4 | 7 |
| Polish | 2 | 7 |
| Total | 13 | 38 |
That is a huge time difference! In my opinion, that increase in speed is a HUGE advantage for vibratory tumblers and was a complete game changer when I discovered it. Using a rotary tumbler now feels like ancient technology. When you start a fresh batch of rocks tumbling it can sometimes feel like the wait to see the finished product is unbearably long – the vibratory tumbler is the solution to that!
A lot of advanced tumbling hobbyists and pros like to use a combination of rotary and vibratory tumbling. If the desired end product is a more rounded stone then you simply can’t skip the first step with a rotary tumbler. It’s the only way to create that uniform shape and there is no substitute for time.
Once that first step in the rotary tumbler is complete, however, there really isn’t much difference in what the end product will look like whether you continue using the rotary or switch to vibratory. That’s why beginning from Step 2 a vibratory tumbler becomes a clear favorite if time is a big concern.
Switching between the two types of tumblers comes with the obvious drawback of needed to own both types. If you get into this hobby for long enough chances are you will end up owning both types so this won’t be a concern, but for beginners it is definitely best to choose one and use it for a while to make sure they want to continue with the hobby.
Rotary Tumblers are Quieter
So far, vibratory tumblers are sounding pretty good. But they also sound LOUD. Neither type of tumbler is particularly quiet, but rotary tumblers are definitely much quieter than their vibrating counterparts.
Depending on your living situation and tumbling setup this may or may not matter to you. Many people choose to put their tumblers in a basement, garage, or work shed so that they won’t hear them in the house. For others, however, it’s just not possible to put enough distance between the tumbler and their living & sleeping space.
If noise is a big concern for you then I would definitely advise you to go with a rotary tumbler. The noise factor is a big reason that a lot of tumblers end up going unused after their first couple of runs. If you’re kept awake at all hours of the night by the sounds of jostling rocks then you’re just not going to use it very much.
Thankfully, there are some things you can do to mitigate the noise levels of both kinds of tumblers. Make sure that the tumbler is filled to the appropriate level with rocks and/or filler material like plastic balls or ceramic media.
I would recommend putting your tumbler on some old pieces of carpet (cardboard would do in a pinch). You can also create a makeshift sound-dampening barrier with an old cardboard box and bedding.
Some rotary tumblers come with rubber barrels which are significantly quieter than their steel barreled counterparts. Don’t worry – they are just as effective as steel. The polishing action comes from the grit and grinding against other stones, not the barrel itself.
I also have another tip for people really limited on space and looking for a solution to their noise problem. Get one of those Christmas light timers and program it to run your tumbler while you’re away at work or school! This won’t work unless the tumbler just has a simple on/off switch, and it will significantly increase the amount of time it takes to complete a full batch since the tumbler isn’t running all the time.
Cost Differences & Potential Savings
Tumbler Price Ranges
Most rock tumblers tend to run in the $75 to $200 range. The rotary tumbler I personally bought and would recommend is surprisingly affordable on Amazon. You can read my full review and why I recommend the National Geographic 3 lb Professional Tumbler here.
You can spend a little more or less, but in my opinion, you should probably keep it in that range. Anything less than that and you’re probably getting something too small and cheaply made. Anything more than that and you’re getting something that’s likely too needlessly over the top for a normal enthusiast’s use.
Up-Front Cost Differences
Vibratory tumblers tend to be a little bit more expensive than rotary tumblers, but not by much. The up-front cost difference between rotary and vibratory tumblers is low enough that it is not going to be a significant determining factor in which type to buy.
An entry-level rotary tumbler will cost you about $50, while a similar-sized entry-level vibratory tumbler will run around $70. Larger, higher-end rotary tumblers with grit and accessories included cost about $120, while the biggest and most expensive vibratory tumblers I’ve seen cost over $200.
Costs & Savings Over Time
Up-front costs aren’t the only thing to consider, however. Vibratory tumblers can actually be significantly cheaper to run over time for two reasons:
- They require less grit per step in each batch of rocks
- They run for less time per batch, consuming less energy
The grit used in rock tumblers can’t be re-used, and it while it isn’t super expensive it isn’t exactly cheap, either. Aside from the rocks themselves (unless you find the rocks yourself) it is the biggest reoccurring expense in rock tumbling.
Vibratory tumblers typically use about half of the grit a rotary would. The exact difference will depend on the model of your tumblers, and what rocks you’re tumbling, but the difference is significant. Also take into account the fact that the first step of coarse grit is skipped in vibratory tumblers, so that cost is usually avoided entirely.
There is also the added electricity cost. As I explained above, vibratory tumblers often require half the time or less that rotary tumblers do. Depending on which models you’re comparing, that electricity cost will add up over a series of weeks and months.
The Bottom Line
Vibratory tumblers may cost a bit more initially, but with each successive batch of rocks that you tumble it will save you a little money compared to a rotary tumbler.
Personally, I don’t think that the cost differences (either up-front or ongoing) are significant enough to be a large determining factor in which type of tumbler you should buy. Get the type and model that will work best for your needs and know that it will be well worth the money.
Vibratory Tumblers Have a Steeper Learning Curve
One big factor to consider when choosing between a vibratory or rotary tumbler is how much experience you have. You don’t want to bit off more than you can chew when starting a new hobby, and there is no sense in buying a piece of equipment that you aren’t comfortable using yet.
Rotary tumblers tend to be a little more forgiving and easier for beginners. There is more leeway in the amount of grit and water you can mix in with your rocks and are a little more ‘set and forget’ than vibratory tumblers. There will still be a bit of a learning curve when you first get started, but chances are you’ll be able to get pretty good results with a rotary tumbler even on with your first batch of rocks.
On the other hand, vibratory tumblers are a little trickier to get the hang of. I don’t want to put anyone off of buying one if that’s what you want to do, because beginners can absolutely have success right off the bat with one. It will just take a little more initial learning and trial-and-error than a rotary tumbler.
In my opinion the easiest thing to screw up with a vibratory tumbler is the ratio of grit and water. The amount of grit you put in should be pretty well defined in the instructions for your particular tumbler model, but nailing down the corresponding amount of water takes some experience.
You want to add just enough water so that the rocks tumble and flow freely while being coated in grit. It should look like a thin slurry covering all of the rocks. Be careful not to put too much water in, though, otherwise the grit will remain stuck on the bottom.
Tip: Use a spray bottle to add water to your tumbler for better distribution and portion control
You’ll also probably want to check on your vibratory tumbler a little more often than a rotary tumbler. Since they work faster the slurry will thicken more quickly and may require additional water to keep the consistency right.
Which Type is Best for You?
If you’ve reached this point you probably have a pretty good idea of which way you’re leaning. If you need a refresher, here is a quick list of the differences, pros, and cons of each:
| Category | Rotary Tumbler | Vibratory Tumbler |
|---|---|---|
| Rock Shape | Well-rounded, more uniform | Retain more initial shape, more character |
| Process Time | Takes longer, ~40 days | Much faster, ~2 weeks |
| Noise | Quieter, but still noisy | Very noisy |
| Cost up front | $50-120 | $70-200 and above |
| Cost over time | More grit & running costs | Less grit & running costs |
| Experience Level | Easier for beginners | More difficult but manageable for beginners |
Which type you use is ultimately up to you – there isn’t a right answer here that will pertain to everyone. There are plenty of people who own and use both! My personal recommendation for beginners would be to go with a rotary tumbler because it’s a little easier entrance into the hobby and they aren’t quite as noisy. The tumbler I personally recommend is the National Geographic 3 lb Professional Rock Tumbler (link goes to my full review).
Once you get into the hobby you will likely get a feel for what you like and don’t like in a tumbler. You may realize that a rotary tumbler just takes too long and you’d rather have a vibratory, or that a vibratory is too loud to stand. The good news is that they aren’t prohibitively expensive, so if you’re enjoying the hobby you can always upgrade or switch types.
If you do ever end up buying a second tumbler, I would recommend buying the opposite type of the one you already own. This way you can really experiment with different combinations in your process and see which type you prefer using. Lots of people start with one type and like them well enough, but once they switch they realize that they actually prefer the one they just bought!