Rock Tumbling – The top 5 mistakes to avoid

Have you considered getting a Rock tumbler?

Many would say no.. Why would I want that? I make Jewelry.. I am not into geology or lapidary!.

Well not so fast! These machines are actually incredibly useful for may other things than rocks.. As a matter of fact for the rest of the post I’ll actually skip the “Rock” part and just call them tumblers.

So what can the tumbler be used for other than rocks then?

  • Well for Jewelers they are especially useful for polishing odd shaped objects. This is achieved by filling up the tumbler with steel shots before adding your jewelry pieces. The shots acts in exactly the same way as a burnisher.
  • They are great for polishing metal clay work
  • Its great if you want to create “sea glass” i.e. matted rounded glass chunks like the once you find on a beach
  • Obviously rock polishing, for Jewelry work semi pressures stones can be shaped and polished and used

There are actually two different types of machines that can be used for “tumbling” one is the rotary tumbler and one is the vibratory type.

Rotary Tumbler

As the name implies this machine utilize a cylinder shaped container that is being spu around at relatively slow speed to create the motion required.

Lortone A3 Rock Tumbler

Lortone A3 Rock Tumbler

Vibratory Tumbler

Vibratory TumblerI guess you can’t actually call this a tumbler in that the method used to create movement i.e. friction is vibration more so than tumbling or rotation, although some machines do have a combination of rotation and vibration.

Both types of machines will be effective in polishing however if you are doing rocks the tumble polisher will create a more rounded look of the rocks where the vibrating polisher will maintain the shape of the rocks better. For Jewelry polishing/burnishing using steel shots the rotating model definitely works best.

Before you buy

So before you rush out an get yourself a machine you need to have considered at least some of the following:

What will you be tumbling

As mentioned above each of the machines have different properties in the method used to create the friction and hence have different results. So if you need to polish rock but don’t want to rounded edges the vibratory model is the way to go. If you on the other other hand want to also do polishing of jewelry a rotating model is the way to go.

How much will you tumble at any one time?

Well size matters.. At least in the world of tumbling if you intend to do big batches of rocks you obviously need a large machine that can handle the load. If on the other hand you only intend to do ne or two jewelry pieces at a time the smallest you can get is the obvious choice.

Are you concerned about power usage

One thing that is often not mentioned in connection with these machines is that fact that they will be running for weeks at a time to create smooth rocks. Most manufactures are recommending 7-10 day per grit in most cases you go through at least 4-5 grits to create a smooth polished rock. So you can do the math that is a fair amount of runtime..

So it may not be worth while picking the biggest most powerful machine you can get your hands on if you really only do small jobs that don’t require a really powerful motor.

Acceptable noise level

Another thing to consider is the location you intend to have the machine running. Depending on the media you use, the objects you tumble and the material and shape of the drum the machine will be more or less noisy. Well that and the motor and general mechanical noise of the machine.

Generally speaking the round rubber drums used by Lortone will be less noisy than a machine using a hard hexagonal shaped plastic barrel.

The Vibrating model will be noisier with steel shots compared to a drum model.

Reliability

No need to go too much into this it is pretty obvious that the machine has to be relyable. No point in leaving it to do it’s thing for 7 days only to come back to find that it only rand 4 hours before overheating or tripping a fuse.

On that point one thing to note is safety.. Regardless of what type of machine it has to operated in a ventilated space so it does not overheat and catch fire. But you also need to consider who have access to the area where the machine is running i.e. if you have small kids or pets is there any risk whatsoever that they can get fingers paws, tails or any other body part stuck or squashed?

Quality

Quality and reliability generally goes hand in hand the better quality mashine you get the better the reliability. As always my recommendation is to buy the best quality machine you can afford. Although it may be tempting to conclude that you will only be running the machine 2-3 times a year don’t compromise on the quality and buy some cheep import.. in the long run you will be much more satisfied with a good reliable quality machine.. That and I guess just as a principle it good to support the local manufactures where ever possible!

Starter Kits

Tumble Starter KitA really great way to get everything (and more) you need to get going is to get a starter Kit. I got mine from a local lapidary supplier called Aussie Saphire Lapidary Warehouse (LINK: https://www.aussiesapphire.com.au).

They have put together their own starter kit consisting of the smallest Latrone 3A rotary tumbler, Different grit abrasives, tumbling media, books, sample rocks to get started on and even a cap and a loupe.. for the price it’s pretty good value I think.

The only additional thing I got was a bag of steel shots for jewelry polishing.

But if you live in the US or any other country lucky enough to be serviced by Amazon, you can find similar rock tumbler starter kits Lortone 3A Rotary Rock Tumbler Kit

there at a much better price.

Tumbling Media

Jewelry Tumbling Media 3

When buying a starter kit you generally speaking get some sort of tumbling media included in the pack. Basically the media is just a broad term for odd shaped “pellets” that is added to the drum.

You normally add media if you have only a small amount of items that you wish to polish so the items are not just bumping into one another or if you wish to achieve a specific effect as an example the burnishing effect using steel shots.

The steel shots I use is a mix of different shapes and sizes the theory being that it will get into all nooks and crannies as opposed to just round shots.

Jewelry Tumbling Media 2  Jewelry Tumbling Media 1

There is an almost endless array of shape, sizes and types of material media available. All have different properties and are used for different types of polishing tasks. The best way is to check the description on the supplies site, find a product that gives you good result and stick with it.

Grid Powder

All of the starter kits come with some array of grid powder from coarse to fine. Like any other sanding or polishing task you go from coarse to fine with some thorough cleaning in between but much more on the actual process of tumbling in the “Mistakes to avoid when Tumbling post”

Like the polishing media there is a vast variety of different powder grids made of different material available all used for different applications.

For Rock tumbling Silicone Carbide is the most used material. But again each manufacture and brand of tumbler recommends different types of grit powder for their specific machine. Like with the media, some trial and error will be required to find what works best for your needs.

When tumble polishing Jewelry using steel shots. You generally don’t add any grit powder to the drum only water and some dishwashing liquid.

What I use

Lortone A3 Rock TumblerI got my tumbler as part of a starter kit from Aussie Saphire it was by far the most cost effective way for me to get a small drum tumbler. The tumbler in the kit is the 3A rotary tumbler from Lortone.

I only really needed a small machine for tumble polishing Jewelry the fact that the kit came with all the stuff needed to tumble rock was just an added bonus seeing my plan was not actually to get into rock tumbling but I gathered that I might give it a go to see what I could get out of it.

As mentioned I bought a bag of steel shots separately but nothing more than that. I chose the Lortone tumbler after having done a fair amount of research online.

The feedback on the machine I could find online was only positive and since the device ticked all the other criteria I had around noise, quality power usage etc. it was an easy choice.

Although I am not a heavy user of the machine I have been very happy with it so far, it is relatively quiet with the rubber drum, the motor itself makes very little noise so I can have it sitting in my workshop running without annoying the rest of the household.

Next Step

So if this a sparked your curiosity I suggest you head over to the “Mistakes to avoid when Tumbling post” where I go through what I learnt on my first tumbling experiments you’ll be amused when you read how I went..

You can also check out the resources page I have put a couple of links there for the top lapidary supply sites.

Let me know your thought and experiences with the different types of machines what have you found works best for which types of tasks?

Have you got some super secret combo of media and grit for a specific task that you can share? I’m keen to try making “sea glass” so if you have the recipe for how to get good results I’d love to hear that too.

Links for more info