Post by TheRock on Oct 2, 2017 23:34:31 GMT -5
Some fine looking granites there braat . Lots of aluminum oxide in those granites you tumbled.
Most felspar is full of aluminum oxide particles.
Granted felspar is softer than quartz but it still has aluminum oxide particles.
Aluminum is the 3rd most common element in the earths crust. Much of it in felspar.
Granite is composed of mostly quartz and felspar. Weathering granite makes felspar rich clay.
Felspar rich clay is often 20-30% aluminum oxide.
So your slurry probably has a higher dose of aluminum oxide than the recommended dose of a tumbling recipe.
Crude albeit, but it's there. And has the ability to put a matte polish on your rocks after the short lived brittle silicon carbide has broken down.
Side note: Ceramic media also has a high percentage aluminum oxide. Denser high quality media typically has higher Al2O3 content. Not all is created equally.
Harbor Freight ceramic media. The cheap stuff. 40% aluminum oxide:
Name 5 lbs. Medium Ceramic Abrasive Polishing Tumbler Media
SKU 60547
Brand Central Machinery®
Abrasive material 49.6% silicon dioxide (SiO2); 40% aluminum oxide (Al2O3); 5.5% potassium oxide (K2O); 2% sodium oxide (Na2O); 0.4% iron oxide (Fe2O3); 2.5% calcium oxide (CaO)
Application Polishing And Light Deburring
Back to naturally occurring aluminum oxide:
Maybe another way of looking at it is looking at the composition of the earth's crust. Note 15% is Al2O3, aluminum oxide.
If you live in a predominately granite area your clay is likely 25 to 30% aluminum oxide.
Since I live in the leading kitty litter producing state (Georgia) I will say that your kitty litter is likely high in Al2O3 if materials came from here.
Fuller's earth is used and it has a high content of kaolin which in turn has a high percent Al2O3(both from weathered/eroded felspar).
Not saying you will get a perfect polish using raw clay or kitty litter. There are other ingredients that will likely impede a great polish.
So Jamesp so are you saying if you are polishing Granites you would have better luck using Aluminum Oxide -VS- Silicone Carbide? If you have any recipies for Granites from start to finish I would like to hear it.. Thanks ~Duke