Rock Tumbling Instructions-Vibratory Tumbler
The following are the most common instructions for general rock tumbling in Vibratory Tumblers to guide you. Many variations can be found in regard to tumbling instructions that make adjustments for different tumbling equipment and different types of rocks. The most important tips are standard. Your tumbler manufacturer may have specific instructions for your tumbler. Presented here are general guidelines and the most common consensus on tumbling methods. You might find the rock hardness information helpful on the Mohs Scale reference.
Be sure to see our grit kit designed specifically for the vibratory tumbler
Rock Tumbling Instructions For Vibratory Tumblers
The tumbling process starts with good rock selection. Pick rocks that are of the same hardness and similar size ratio (the biggest should be no more than four times the smallest) to coordinate their development in the tumbling process. Gather enough rocks to fill your barrel between 2/3 and 3/4 full. Avoid using unusually odd and non-rounded shaped rocks with the more common rounded shapes as these will be more difficult to sculpt.
Rotary tumblers use a three step goal oriented tumbling process:
Between each of the four steps remove, thoroughly rinse your rocks, clean out the barrel and remove any grit or rock debris. This is really important as the coarser grits from one step will act adversely in proceeding steps,scratching rocks as you are refining them with finer media. As always, it is advised not to throw used grit down a drain as plumbing will be damaged. Use a bucket and a screen to collect used grit and slurry.
Step One (Grind)
The goal of this step is for all surfaces of your rocks to be well-rounded.Place rocks in the tumbler and add the 120/220 silicon carbide grit. You are looking to round your rocks in this step over 7 to 10 days. The Grit to rock ratio here is 2 tablespoons of grit per pound per pound of rock. Add water until it is just below your top layer of rocks. Some of the rocks may be now too small or too odd to continue working with them, so you will remove these rocks. Your goal again in this step is to see that all the scratches from the first step are ground away, and the rocks have a smooth, matte finish. Using a magnifying glass may help check for smoothness. If that is the case and once you see rounding has occurred for most or all of your rocks this move on to step 2.
Step Two (Pre-polish)
In this step the goal is to make the rocks extremely smooth. As always start as with Steps One and Two, put cleaned rocks in the cleaned and fresh barrel to make a full load. Use a pre-polish of either silicon carbide 500 or aluminum oxide 500 for this step, about 1 tablespoon per pound of load, and then add water up to the bottom of the top layer of rock. Tumble time here is up to 7 days, with more checking slurry consistency and general progress every day or two. You may be pulling some of the rocks out earlier than others as they will become smooth sooner and even show some luster. For softer rocks, you may need to do a second pre-polish step or just keep them in a little longer. At the end of this step it is most crucial to really clean the rocks and barrel which will be more difficult as you are using a finer grit. This is so important because any grit can ruin the progress of your rocks in the final polish step.
Step Three (Polish)
By this time your rocks are looking pretty good and ready for that lasting final shine. You have been extra diligent on cleaning the rocks and barrel. Place your rocks in the tumbler and add Aluminum Oxide Polish, about 1 tablespoon per pound of rock. Step four takes up to seven days but be sure to check the rocks as you are proceeding because some will be finished earlier. The best check for completed rocks is that they look as now as they would if wet. Once that is the case you are done with this step. One final detail, its best to clean up now by cleaning your equipment thoroughly before everything dries and encrusts. So you'll be ready for your next project with rock tumbling.
If you have a Rotary Tumbler we have instruction for those here.
General Tips for Tumbling and doing Pretty Much Anything Else
Belief that you can make something great
Attention to detail