Last update (this page): January 8, 2010
This website exists to gather in one place all the practical advice and information I can share based on my years of rock tumbling (tumble-polishing). I started in about 1994. Why maintain this site? It's a fun hobby and I want to share the fun.
More philosophically, as Edward Abbey put it perhaps awkwardly yet with deep meaning: Rock gives reality to the otherwise abstract notion of transhuman time. Making pretty, shiny things out of dull, immortal stones is reward enough. But on top of that there's a certain satisfaction and humility arising from the recognition that one of your polished stones could re-emerge and be appreciated by some intelligence in literally millions or even billions of years, long after the time when its creation has become a mystery and its polisher forgotten.
Anyway, back to Earth! There are many printed booklets on the subject too, and most tumblers come with instruction manuals. (See for example www.lortone.com; the photo nearby is of their 12 lb and 3 lb units running in my tumbler shop, along with buckets of rocks on the left, silicon carbide on the right, and an eyedropper bottle of motor oil against the wall.) But as you can see from the size of this website, there's a lot more you can learn about the subject than the essentials they cover.
There are many other websites out there that talk about tumbling, for example this one is amazing.
And here is a section of a website that discusses science and experimentation around grit sizes and effects.
I intend this website to be complete and sufficient enough that you can have fun and success rock tumbling without reading anything else, except the instructions that (hopefully) came with your equipment, as there are manufacturer-specific differences in lid and seal designs, lubrication needs, etc. Of course I welcome your comments, corrections, and additions.
My limited experience with vibratory tumbling was not good, so mostly this website talks about rotary tumbling. While the latter is slower, I think it's a lot easier and more reliable.
As a hobby, rock tumbling is relatively cheap, easy, and not time-consuming. However, it can also be disappointing if you dabble in it without a little bit of knowledge. Most rocks won't take a shine, and there are some simple mistakes you should avoid, like overfilling the barrel or letting the unit run too cold (freezing) or hot (bad for the motor).
Finally, bear in mind that things worth doing for fun are worth doing badly, there are no rules, and it's OK to explore and experiment. Also, tumbling requires patience. Vibratory tumblers are faster, but correspondingly require more babysitting and are more sensitive to error. Remember that you are speeding up a natural process that takes much longer, even on a beach, and taking it further too.