Tripoli as a slurry thickener for Tumble Polishing

I have a friend that gets a fabulous final polish, on both 7-mohs stuff and obsidian, using nothing but tripoli and water. However, he re-uses his polish slurries indefinitely, adding a bit more tripoli each time, so it gets as thick as pea-soup. He also runs the polish stage for a month. He is known as a tumbling guru in his area, and does this professionally. When he sells his polished rocks at gem fairs they are the envy of the other vendors. However, I know most people consider tripoli just a pre-polish. I guess it depends on how you use it, and my friend has hit on a formula and process that excels for him.

That said, I don't have a clue whether it's a good idea to mix the two grits. However, I'm nothing if not an experimenter, and I've definitely gone against the grain of established lore, but that fact has led to some fun breakthroughs that I have shared on this forum. My biggest hesitation here is frankly the cost of the grits if it doesn't work out. Even tripoli can become expensive if you use enough of it really thicken a slurry to the pea-soup stage. I think cost is why my friend stumbled onto reusing his slurries, and then he fell in love with the results of having a super-thick slurry.

If you decide to go for it, please post back with your results.

Cheers!

The aluminum based felspar clay I use as a slurry thickener in the rotary in coarse and AO 500 stage is apparently 35% aluminum oxide.
Being that I use 3 to 4 cups at each clean out the aluminum oxide content is like 1 cup of AO for 8 pounds of rock or glass.
Running the last addition of coarse SiC for a week with the AO rich clay yields a vibe ready finish. This clay is a rock tumbler's delight.

Running glass I use SiC coarse in the rotary and then a quick AO 500 in the rotary for security measure, both with clay, then to the vibes.
The clay here is used for firing aluminum oxide ceramics. No question about it's composition of aluminum oxide.

The clay is referred to as kaolin and occurs from erosion of felspar bearing granite.
It averages 40 feet deep in the Atlanta/peidmont zone of N Georgia.

5 million tons mined in 2011:

"In the US, the main kaolin deposits are found in central Georgia, on a stretch of the Atlantic Seaboard fall line between Augusta and Macon. The deposits were formed between the late Cretaceous and early Paleogene, about 100 million to 45 million years ago, in sediments derived from weathered igneous and metakaolin rocks.[14] Kaolin production in the US during 2011 was 5.5 million tonnes.[15]"

Problem is they rarely sell it in bags, usually by the train car load.
Or it can be dug from most any spot in N Georgia but will have some quartz sand in it. OK for rotary up to 500 grit.
The kaolin mines separate the silica from it in massive operations, then it can be used in the vibe.

Kaolin magnified(felspar platelets)

Bob. Explanation for where you have been please.

Hi Henry,
I know I am resurrecting an oldie here, but may I ask: how'd it turn out using tripoli as a thickener?

I've been experimenting with it lately, and I like the slurry consistency it produces! I just used it as a "polish" for rose quartz and I thought it worked real well.