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Post by Starguy on Oct 22, 2022 13:02:33 GMT -5
I hear you. You can stretch polish a long way too. Whatever you did, they turned out great. They must have run in the rotary for quite a while or were they wave tumbled?
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Post by Son Of Beach on Oct 22, 2022 14:39:15 GMT -5
I hear you. You can stretch polish a long way too. Whatever you did, they turned out great. They must have run in the rotary for quite a while or were they wave tumbled? Thank you, trying to be patient so they can be that match of nice shape and finish. I run them at least one week in coarse, but the waves did most of the action
Some run for months, I'm sure you know the feeling with your bots...
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,564
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Post by jamesp on Oct 23, 2022 10:03:59 GMT -5
RTH taught me to use AO. Never looked back. Others have used tin and cerium oxide and had great results. If the polish is hard enough to polish a hard rock to a 1 micron surface level then all should work out fine. Notes on the flexibility of AO: It's been mentioned over the years(and my experience) that(Rock Shed's) AO 500 will reduce in size in a Lot-O and other brands of vibes to polish sized particles in 3 to 7 days depending on conditions. Note that AO 500 doesn't reduce as well in a rotary, but one more rotary step of polish will bring a fine polish. That is what sold me on AO. The only proof that the AO 500 is breaking down unless someone looked at it under a microscope is the 1 micron+ level polish AO 500 lays down in those vibes. For that level polish to happen the AO 500 sized particles have to reduce in size in harmony from their 35 microns size to .5 to 1 micron size which is amazing. For reference 35 microns = 500 grit, 1 micron = 14,000 grit, and .5 microns = 50,000 grit. Playing devil's advocate comparing diamond, diamond 500 would never meet that size reduction performance because it is so much harder than aluminum oxide and all other abrasives. Diamond is noted for its ability to not wear down and it would probably maintain its 500 size for months in a vibe and no polish would happen for a very long time. By the same token 1 micron diamond polish would likely not reduce from a 1 micron/14,000 polish to a .5 micron/50,000 grit polish. IMO many members tumble polishes easily move into the 50,000 to 100,000 grit level polishes due to reduced size abrasives. Jewelers commonly use .5 micron/50,000 diamond paste on their work. 50,000 and 100,000 grit polishes are those that are just blow you away shiny. There is no other way to have a dead wet shine unless the worked surface is .25 to .5 microns. Unakite and other Mohs 6 or less rocks are more of a challenge to get a high polish on. Back to the tin oxide, a great test would be to run tin oxide 500 in a Lot-O and see if it will reduce in size to the point it will polish a batch like AO 500 does. Nice to be able to skip fine steps when able. If an any type of tumbling abrasive will go to(or close to) polish level from a much larger size it is a fine abrasive. This would be an example of a .25 to .5 micron polish and it was accomplished by running giant AO 22(!) in a vibe for 10 days. A testimony as to how flexible aluminum oxide can be: PS Chad it is real tricky taking photos to compare polishes. I finally figured out how. Best is to have lots of light and excellent reflection as in the above photo. The one pound rock was run in a vibe in 100% quartz pea gravel with no other larger rocks to possibly damage the delicate polish surface. It is not required to run a rock in 100% media to get a super polish but it does reduce chances of a damaged polish especially when running a 1 pound rock. Some of the highest polishes are gotten when the batch is all small hard agate type rocks.
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jamesp
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Member since October 2012
Posts: 36,564
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Post by jamesp on Oct 23, 2022 10:45:28 GMT -5
Starguy Garnet, especially high grade almandine breaks all kinds of records for being one of the 'toughest' abrasives on earth. Rocks can be hard but they also have another property called 'tough'. The Mohs test is ok for testing hardness and toughness. The Knoop test is much better for testing toughness. This issue comes into play when sandblasting and impact tumbling(like in a rotary) is involved. Almandine garnets can be shot at tough steels for many cycles before breaking down to smaller pieces. Silicon carbide is much harder and cuts faster but shatters like glass into tiny particles after being shot once rendering it useless for such an application after that. That is why water jet drilling machines use good ole almandine garnet abrasives for jetting say a long 4 foot long tiny hole in a chunk of tool steel. They toss the almandine garnet when it rounds and smooths to the point it won't cut well. Granted some of the garnet particles do crack into smaller pieces. I remember those large garnets you tumbled. That must be a slow process. If tin oxide polishes those garnets that says a lot about tin oxide.
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Post by Starguy on Oct 24, 2022 10:56:08 GMT -5
jamespTin oxide worked great for the garnets. I have some polished sand size jars around here somewhere. It’s funny that the Caddis Fly larvae in Emerald Creek incorporate the garnet sand into their protective casings.
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,564
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Post by jamesp on Oct 24, 2022 11:34:31 GMT -5
jamespTin oxide worked great for the garnets. I have some polished sand size jars around here somewhere. It’s funny that the Caddis Fly larvae in Emerald Creek incorporate the garnet sand into their protective casings. Wow, that is crazy. Any idea why garnet would serve them ? My concern about the tin oxide was that it was too soft to grind/polish that hard tough garnet. That answers a big question right there. There is few rocks tumbled on RTH that is harder than that rock ! I tried tumbling those BB sized almandines and finally gave up as it was taking a long time. Better to run them over and over as media perhaps. The guy I bought the garnets from - he said 100 and 300 grit emerald creek garnets are used in commercial water filtration systems. The filter is back washed constantly and the garnet sand gets pulverized constantly in the 'bead filter'. Those garnets were the most durable substance for the job but do need replacing after X hours/days. China made almandines ! lol
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Post by Son Of Beach on Oct 26, 2022 18:08:32 GMT -5
jamesp I keep coming back to the amazing shine on that stone.
Maybe it's worth trying a couple extra days on polish.
I just can't seem to get the shine others like yourself have put out.
As for pictures, I try to capture the rock itself rather than the glare so you can see the details a little better.
Your example hints maybe I should a different angle once in a while
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,564
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Post by jamesp on Oct 27, 2022 6:44:56 GMT -5
That rock was polished by itself with AO 22 in a vibe with 100% quartz pea gravel Chad. No AO 500 or AO 1000, just AO 22 after step 1 in SiC 30 in the rotary. i.e. 2 steps - SiC 30 in rotary and AO 22 in vibe. Just to be clear, AO 22 grit is giant at 800 microns or 1/32" in size. And that rock is a very hard piece of agate(waxy like surfaces). Hard agates are easier to polish than softer ones like some unakites. So when the rock was finished after 10 days the AO 22 particles were still in tact but rounded into tiny small balls. Conclusion - The AO 22 'rounded' off to tiny polishing balls(another term used is 'broken down' for smaller AO grits). For example AO 500 may 'round off' too but the particles are too small to see when doing a clean out. Can't prove that. But did prove that larger AO particles can round off (or break down) and impart a fine polish. Jugglerguy sent me a MFRB of Great Lake unakites and I was challenged in polishing a lot of it. I guess it depends on it's silica content ? Another member sent impactite from the Great Lakes area, same issue, it was difficult to get a high polish on it. Separate subject: Tumblers - My adjustable Vibrasonic vibe would not polish(soft/tricky) obsidian or glass. I tinkered with the adjustments and thickened the slurry until it ran gentler and finally it would polish glass. So the(minimal) tumbling schedule for glass and obsidian became this: rotary till rounded using SiC 30 vibe - 2 days in SiC 500(SiC 500 is a cutting abrasive and is much more aggressive than AO 220) vibe - 3 days in AO 220 Vibe - 9 hours in Rock Shed AO polish(AO 14,000). So the AO 220 was obviously breaking down to 500-1000-4000 or something like that for the AO 14,000 to do the polish step. BUT, if I put any chunks of glass in the batch over 30 to 35 grams the whole batch would not polish as well. The heavier pieces of glass mechanically(micro) damaged the 10 to 20 gram pieces. I noticed your tumbles in this thread are quite large like 60 to 80 grams. Try tumbling a batch of smaller rocks say 10 to 25 grams with no larger rocks. Lots of well polished rocks posted here are small rocks and the photos can make them look large. I don't think I could lay a polish down as good as yours that you posted here. Especially the unakite, those larger quartz cobbles, maybe the jasper and some of those others. If the stone rounds quickly in step 1 there is a good chance it is not going to get a high polish. Try Brazilian agates, Montana agates, moss agates, and similar 'glassy/waxy' agates, these are very hard and take a long long time to round off in step 1.
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