Hi Quinn, Danny looks like he has worked out a way to get a good full polish on his stones using the diamond powders/pastes and he has polished a lot more stones than me...I'm sure there are several solutions. I will try his way with the wooden drums and a bristle brush at some stage.
It's basically about a process of sanding, going through the range of grits 400 - 3000 removing all the scratches from the previous grit (clean up the piece and tools after each grit) until a molecular change occurs
where the scratches are so fine you can't see them with the naked eye. Easier said than done he says!! Yep that's right, this is a patience game where skipping ahead won't work what ever method is used.
If you think you have all the scratches out at 3000 diamond you could then try going to 2000 then 3000 grit silicone carbide sandpaper wrapped around rubber drums or sticks, dowels etc to get a pre-polish.
Do this process dry and you will soon have a good shine. (Using a quality face-mask and dust extractor of course as the fine particles from dry sanding are toxic). Water can be used at this stage too.
I don't often like things too reflective and polished, but to get a full-polish I use:
1. Diamond grinding wheel, burrs and point carver for shaping
2. Silicone carbide rubbings sticks to refine shape
3. 3M diamond cloth 400, 600, 1200 with water (sanding in multiple directions) and sometimes diamond paste and hardwood sticks in hard to get places
4. Silicone Carbide (wet and dry) Sandpaper 800, 1200, 2000, 3000 (sanding in multiple directions, wet then dry for the 800, 1200 and just dry at 2000 and 3000 for a pre-polish)
5 Tin Oxide and water slurry on soft leather around drums, with heat and pressure (like Kenneth's but no diamond) when it pulls on the piece it's polished! Just keep moving in all directions until it pulls on all surfaces. The work area and piece must be spotless for this process.
This is probably the old-school way, but seems to work on a lot of different materials. Even though I have tried a lot of the expensive diamond technologies out there, I find I often come back to a simple piece of sandpaper in my hand.
Each stone is a different beast...I have never tried for a full polish on obsidian, but the 3000 grit sandpaper certainly gets it very close. As I have heard said here before some stones just don't want to polish at all or have too many inclusions (hard and soft areas)
so we just have to stop and be satisfied at the stage we think the stone looks it's best. We all also have our rejects pile!!
Good luck in your stone sanding meditations. Jason