Tumbling: What size barrel, how much media?

How to choose the right size tumbler for your job (Aussie Sapphire) When deciding what size tumbler to use, it can be confusing comparing all the different types available. This article provides all the dimensions and volumetric capacity data you need to help choose the right size for you. (copyright Aussie Sapphire)

When deciding what size tumbler to use, it can be confusing comparing all the different types available.  Combined with this, many tumblers are manufactured in the USA and specifications are quoted in a range of imperial units.

The other difficulty is that a range of tumbling media can be used and it can be very confusing trying to work out how much is needed. To help overcome some of this confusion, Aussie Sapphire has measured a range of tumbler barrels and bowls as well as the bulk density of a variety of tumbling media to assist you in making the right choice.

Please download this pdf document which gives dimensions, weight, volumetric capacity and recommended load limits:

Information on Tumbling Barrel/Bowl Size and media Density


Although tumblers are usually described in terms of a weight rating, it is not actually the most useful measurement - it is more important to think in terms of available capacity in terms of volume. So the datasheet in the link above describes all the models in our range in terms of litres of volume so you can easily visualise how much space you have to work with and compare it to a batch size of the material you will be working with. 

When choosing a tumbler for rock tumbling, remember you need to fill the barrel to optimal level.  This is about 2/3 full - if you tumble rocks in a barrel more than 3/4 full, there is not enough room for the rocks to tumble freely but if you fill the barrel less than half full, then the tumbling action is far less efficient.  If you get a tumbler that is too large, then you need to make sure you have enough material available to load the barrel efficiently or you will need to use a lot of filler media (eg. porcelain shapes). If you choose a tumbler that is too small, then it can be frustrating not to be able to tumble enough material at once or have to break up rocks that are too large.  

The rule of thumb when rock tumbling is the use a MIX of sizes up to about half the diameter of the barrel.  Use the data in the info sheet above to determine the maximum size for each model.  Dont add too many large rocks so that the load wont move freely within the barrel.  Make sure you do include smaller rocks in the load as these help to grind the whole surface of the rocks evenly.

Please note that this information has been compiled by Aussie Sapphire from a range of sources including users instructions from manufacturers.  It is intended to assist our customers but you should always read the owners manual for your particular tumbler and not rely solely on the information presented here.