Selecting the Proper Tools for Polishing Rocks
There is nothing like seeing the transformation of seemingly ordinary rocks as they are polished into beautiful gemstones. There are a number of options available to help you polish your rocks.
There are a number of factors that you should consider when selecting a polisher including, the size and shape of the rock, cost, and processing time.
The following guide will help you to select the polisher that is right for you.
Rotary Tumblers
Rotary tumblers are what most people think of when it comes to rock polishing. They are the most common method used to polish rocks today. The action created by rotary tumblers simulates the action of waves or rivers as they wear down the rock eventually rounding them and giving them a shiny finish.
Using rotary tumblers is one of the slowest methods of polishing rock however they are also the most affordable of all the 5 methods.
Completing the process using rotary tumblers takes several weeks. Rock is added to the tumbler as well as water and a quantity of grit. Coarse grit is used at first and finer grit is used after the rock has polished for days or even sometimes weeks. The process is continued with finer and finer sizes of grit until eventually only a polishing compound is needed as the final process.
Between each phase of polishing it is very important to wash the rock as well as the tumbler completely before moving on to a smaller grit. Many people use toothbrushes or tumble stones in Ivory soap between steps. If there is any grit leftover from the previous step it will contaminate the grit used in the subsequent step and you will not get a good final polish.
Rotary tumblers can also be used for metals with the use of stainless steel shot.
Source: Wikimedia commons
Vibratory Tumblers
Vibratory Tumblers work very similarly to rotary tumblers except they work much faster. What takes weeks in a rotary tumbler will take only days in a vibratory tumbler.
There are several types of vibratory tumblers available the lowest cost ones are designed for metals such as shell casings or jewelry. These machines are not ideal for using with rocks. They usually have a low weight capacity and are not designed to hold water.
For use with rocks, you should use a vibratory tumbler that has a heavyweight capacity and a liquid drain hose. For this reason, it is best to select a wet/dry polisher.
Vibratory tumblers do not round the corners of the stone as much as rotary tumblers so your stone will keep its original shape better rather than becoming rounded.
Sonic Tumblers
Sonic tumblers are usually quite a bit more expensive than rotary or vibratory tumblers however they work faster than either one. Sonic tumblers have little or no moving parts so they tend to require less maintenance or replacement parts.
Flat Lap Vibrating Polisher
Flat lap vibrating polishers are a specialized type of polisher used to polish flat stones such as bookends or coasters.
Wheel Type Grinder / Polisher
Wheel type grinders/polishers are by far the most expensive method of polishing rocks however they are also one of the fastest.
Using a wheel-type polisher with diamond wheels you could shape and polished a finished cabochon in a few minutes with the proper experience.
Don’t expect those kinds of results the first few times you use a wheel-type polisher or a grinder. Speed and gemstone quality increases with experience with this type of polisher.