The main principle in polishing stone is to start with a coarse abrasive for grinding, and work through a series of increasingly finer abrasives to the final polish. The whole process is basically this simple, but there are variations in gemstone properties, types of abrasives, many recommended grit (abrasive) sequences, and results produced by the different types of tumblers. All these variations and choices can be confusing, especially to a beginner, so it should be remembered that tumbling is basically simple, not an “exact science”, and can be great fun once the basics are mastered.
The first choice to be made is the type of tumbler to be used, Rotary or Vibratory. A brief description of the two types is given on our types of tumblers page. Further descriptions can be found on the pages of the catalog listing the tumblers themselves.
Both rotary and vibratory tumblers use the standard silicon carbide grits with water in the mix as well as a filler of some type. However, Vibra-Dry mixes can be used in vibratory tumblers for the polishing steps, and produce higher polishes on almost all stones and metals. Vibra-Dry mixes do not use water, and can be re-used multiple times.
The beginner should be aware that some stones will not polish in either type or tumbler nor with any grit sequence. In order not to waste your time and money, be selective. See page on “Selecting Stones”.
Over the years, individuals have developed procedures and grit sequences that give them good results, but what works for one person doesn’t always work for someone else. As a result, you will find that advice, books and manufacturer’s instructions vary in their recommendations. All follow the basic principle of tumbling, but reading “Use 80 grit to start” in one source and “Use 60/90 to start” in another is confusing. Both work, and there is actually little difference between those grit sizes. In fact, most grit sizes that are used actually cover a range in particle size. The 60/90 range includes 80 grit, a sample of 220 grit might range from 100 to 300 in particle size. Finer grits and polishes are more closely graded so that particle size is more uniform and so are the results. As a consequence, finer grits and polishes are move expensive
Fillers are recommended for use in both types of tumblers and in each step in almost all grit sequences. Fillers soften the action, fill space between stones, and carry the grit to the stone’s surface more efficiently. Fillers generally can be reused if thoroughly cleaned between grit sequences. We recommend the ceramic bits for both stones and metals as they seem to do the best job and will last longer.