How to Use a Rotary Rock Tumbler

Open the barrel of the rock tumbler. If the rock tumbler is new or hasn’t been used in awhile, you may need to use a butter knife or flathead screwdriver to pry off the lid.

Add rocks to the barrel. Make sure to fill the barrel 1/2 to 2/3 full of rocks. If you put too much or don’t put enough rocks in, the rock tumbler will not work properly. For best results, use rocks of assorted sizes, but make sure each rock is at least 1/4” in diameter.

Add the Coarse 60/90 Silicon Carbide abrasive. The amount you use is dependent upon the size of your rock tumbler and the amount of rocks you have loaded into it. In general, add approximately 1.5 – 2 tablespoons per pound weight of your barrel. For instance, if you are using a rock tumbler with a 3 lb. barrel, add 4.5 – 6 tablespoons of the abrasive. Use the lower end of this amount if the tumbler is only 1/2 full and the upper end if it is 2/3 full.

Add enough water to the rock tumbler to just barely reach the top layer of rocks. Be careful not to overfill. Too much water will cause the rocks to not tumble effectively. Some people choose to add a little bit less water in order to speed up the tumbling time a bit. You may want to try this after you have had some practice using the rock tumbler.

Replace the lid on the barrel and wipe off any excess water and debris with a clean rag. If the tumbler is new, it may be hard to get the lid to fit snugly. If you have trouble with this, apply a thin coating of dishwashing soap around the inside edge of the outer lid. This will help it slide in place easier. Don’t close the lid too tightly. It only needs to fit snugly.

Place the barrel on the tumbler and plug the rock tumbler into a nearby outlet. Remember that the rock tumbler will be running for several days so make sure that it is located in a place where it will not be in your way.

Check on the rocks every 2-3 days. After 5-7 days, depending on the hardness of the rocks, unplug the rock tumbler and remove the barrel. Rinse the rocks and the barrel in warm soapy water. Don’t dispose of the rinse water in a household drain.

Repeat Steps 1 – 7, substituting the abrasive in Step 3 with progressively finer grit: Medium (120/220) Silicon Carbide, Aluminum Oxide Pre-Polish, and, finally, Aluminum Oxide Polish.