Lapidary Equipment Supplies

Rock Tumbling is a fun project that the entire family will enjoy. It will take some patience, but it is a fun way to use special rocks you collect. The end result will be a beautiful selection of rocks that you can think of lots of uses for. A few ideas: add interest to the dirt in your houseplants, add to a vase for use with flowers, put in a shallow bowl in a display area such as a bathroom.

 

How to tumble rocks: With a tumbler, you will start out with a coarse grade of abrasives, tumble for about 10 days, check progress and then change the abrasive to finer and finer grit until the surface becomes smooth. Rock tumbling projects should always be supervised by an adult. Generally, you simply add water and an amount of silicon carbide grit as an abrasive to smooth and shape the stones. In the initial tumbling phase, you may also add small chips of rocks to aid in the smoothing process. The abrasives used: coarse silicon carbide (60/90 grit), medium/fine silicon carbide (120/220 grit), polish material and reusable plastic pellets. The process takes about 4 weeks, unless you are starting with smooth stones, and then it may be slightly less.

 

How to Choose a Tumbler:. When you buy a rock tumbler, you will get what you pay for. A rock tumbler sold as a toy will be prone to breakage and the failure of rubber belts and components will end up being more expensive than you may anticipate. Also, a cheap plastic barrel will be noisy and will generally indicate an inferior quality of machine. The replacement of belts will be expensive enough that you may as well buy a better machine (you can even find used ones) than buy a cheap tumbler. Quality built tumblers are built with a sturdy metal base, a motor and a thick rubber barrel, to minimize the noise from the tumbling. Good tumblers are designed to give you a smooth polished finish on rocks, glass, and can be used on metal fragments. Some of the nice quality tumblers include Thumlers, Lortone, and Diamond Pacific although the latter is quite expensive. We have read that the tumblers made by Harbor Freight (Chicago) have belts that break easily.

 

Size of Tumbler: You will be running your tumbler for weeks, so you want to size your batch to your tumbler. You will want to fill your tumbler between 2/3 and 3/4 full to get the best tumbling results. For home/hobby size with rocks about 1 to 1 1/2 inches, you can use a 4 1/2 to 6 lb tumbler. For stones about 1 inch maximum, a 3 lb tumbler will work fine.

 

Rotary vs Vibratory Tumblers: The vibratory are less capable than a rotary tumbler, and they often require continuous addition of water (every hour). A well made rotary tumbler with a rubber barrel will be much quieter than a vibratory tumbler. The vibratory tumblers are used for material which is already formed, and is not useful for rough rocks.

 

How to Choose your stones: Some will take a polish and some will NOT. Rock tumblers can only bring out the NATURAL beauty in the stones. Rocks and stones typically used in gravel and driveways do not tumble and polish well. As a check of your stones, clean then and wet them with water. If there is some color and some interesting texture, the stone will probably be a good tumbler. For best results, the stones should be somewhat similar: keep rough stones with rough, and smooth stones with smooth to achieve consistent results. Also, if you can determine the hardness of the stones, keep them compatible. Sandstone will not work at all with agate!

 

Buying stones: There are several reputable sellers on Ebay that sell stone lots for tumbling. We have a favorite seller listed on our website that has provided us with lovely, colorful stones. We have purchased 10 lbs which fits into a 8.95 postal box, which makes shipping cheaper than you may expect. Read seller feedback and a high feedback will probably provide you very nice stones.