Silicon Carbide or Aluminum Oxide that's the question.
Let's discuss preferences for Tumbling pre-polish. The common preference for use of a pre-polish in step 3 of the standard rock tumbling process is to use either Silicon Carbide or Aluminum Oxide 500 which are about the same grade of 500.
So which abrasive media is best to use? Many prefer SIC to ALOX and that is because of the relative hardness of the SIC. Without any doubt it just holds up better throughout a long tumbling cycle. That is chemistry and there is no getting around the realities of the atomic makeup of these two compounds.
So people say, well my job will be done by the abrasive for a longer period of tumbling. While this may be the case it is often overkill. If I am driving across the country it may be nice to have a really cushy seat. But if I am just driving down the street, I probably won't even notice before I am out of the machine. And thus with abrasive media, it is the case then that Aluminum Oxide is a perfect pre-polish and this is the truth with most small barrel capacity name brand tumblers like Smithsonian and National Geographic.
Recommended by the Manufacturer
We follow the manufactures guidelines and provide the item that they recommend for you in this pre-polish step.