jamesp
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Post by jamesp on Dec 30, 2020 6:35:29 GMT -5
This experiment was done in the rotary and the Vibrasonic vibe using 11 pounds of Madagascar fluorite and tumbled glass media on the first attempt. The fluorite after being shaped in the rotary. It was fractured heavily when purchased. The fluorite was moved to the vibe and run with tumbled glass media using steps of aluminum oxide with no success. IMO the fluorite and the pea sized glass was not hard enough or big enough to break down the hard aluminum oxide. Fluorite at Mohs 4 and glass at Mohs 5 is no match for breaking down aluminum oxide at Mohs 9. Perhaps many steps of AO would have done the job. Say 220-500-1000-2000-5000-14,000. Maybe... So about 6 pieces of the least fractured fluorite was tossed into the vibe and run with agate with steps of aluminum oxide. Hail Mary style. The agates are certainly hard enough to break down AO 220-AO 500-AO 1000-AO 14,000 and ended up with a polish. The fluorite followed suit ! So the 6 pieces of fairly well polished fluorite.
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Post by orrum on Dec 30, 2020 7:34:41 GMT -5
Great thread Jim.
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kyoti
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Post by kyoti on Dec 30, 2020 9:38:32 GMT -5
That's amazing! I wouldn't have expected the fluorite to survive being tumble buddies with the agate in the vibe. Did you use a lot of ceramic media?
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jamesp
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Post by jamesp on Dec 30, 2020 11:27:29 GMT -5
That's amazing! I wouldn't have expected the fluorite to survive being tumble buddies with the agate in the vibe. Did you use a lot of ceramic media? 100% agate(coral) in a real good range of sizes kyoti go figure. Dropped my jaw too.
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Post by jasoninsd on Dec 30, 2020 11:28:04 GMT -5
So, out of that entire batch of rocks, there was a yield of 5-6 rocks that would be considered "good"...I don't feel so badly now!
That's not meant as poking fun at you or this tumble...rather, I feel better about some of the results I get with regards to what would be considered well-tumbled rocks. So many of what I thought would be good, turn out to have too many pits or fissures I feel they just need to become driveway gravel...
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Brian
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Post by Brian on Dec 30, 2020 21:15:09 GMT -5
Those pieces turned out lovely! They almost look like some of the glass that you tumble.
If you believe that the glass and fluorite alone weren't able to break down the aluminum oxide, do you think you would have any success in adding just a few pieces of harder material? In other words, how much harder material would need to be added to break the aluminum oxide down?
I'm still very much in learning mode, so I'm curious what your experience would tell you.
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jamesp
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Post by jamesp on Jan 1, 2021 8:09:24 GMT -5
The whole batch turned came out polished jasoninsd, the coral and miraculously the fluorite.
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jamesp
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Post by jamesp on Jan 1, 2021 8:43:47 GMT -5
Those pieces turned out lovely! They almost look like some of the glass that you tumble. If you believe that the glass and fluorite alone weren't able to break down the aluminum oxide, do you think you would have any success in adding just a few pieces of harder material? In other words, how much harder material would need to be added to break the aluminum oxide down? I'm still very much in learning mode, so I'm curious what your experience would tell you. That was my question Brian. About the best ratio was 30 to 35 percent mohs 7 pea gravel with 65 to 70 percent glass using AO 220 and AO polish in the vibe. 3 days AO 220, 1 day AO polish to brilliant polish. 20 to 25% quartz gravel took twice as long to polish and the final polish seemed a bit off on occasion. 50% quartz gravel broke AO down a bit quicker and always resulted in a brilliant polish. The AO 500 and AO 1000 step was skipped meaning that the AO 220 broke down to pre-polish. This HAD to happen. Resulting in a 2 step polish using only AO 220 and AO 14,000 polish.(in my vibe, perhaps not a different vibe...) Playing devil's advocate - what if Mohs 1 talc was being run, it is doubtful Mohs 9 aluminum oxide would ever be broken down. There must be some formula saying that abrasive must be softer for softer rocks. Maybe 2 Mohs notches higher than target rocks(most tumblers do Mohs 7 rocks with Mohs 9 AO and SiC).
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jamesp
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Post by jamesp on Jan 1, 2021 8:48:36 GMT -5
Note pocked surface of flourite to left. No explanation for why some of the fluorite had this defect.
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Post by HankRocks on Jan 1, 2021 9:07:28 GMT -5
Note pocked surface of flourite to left. No explanation for why some of the fluorite had this defect. Just a guess, but it may be due to orientation of the crystal structure to the surface being polished. Or maybe the presence of impurities.
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Post by jasoninsd on Jan 1, 2021 10:45:21 GMT -5
The whole batch turned came out polished jasoninsd , the coral and miraculously the fluorite. I misunderstood...now I'm back to feeling totally inadequate about my tumbles.
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jamesp
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Post by jamesp on Jan 1, 2021 11:00:05 GMT -5
The whole batch turned came out polished jasoninsd , the coral and miraculously the fluorite. I misunderstood...now I'm back to feeling totally inadequate about my tumbles. Well Jason, once you get the recipe to perfection I suppose it is easy to tumble. It did not come easy to for me. I had a 3 pound tumbler when 13 years old and scored well with first attempts. Even polished Apache Tears. 40 years later I started tumbling again and must have messed up a half dozen loads before dialing in. This experience was very humbling. You know you are at the right place for best advise. I'd do it right by the book till you succeed. Good luck. And Happy New Year of course !
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Post by jasoninsd on Jan 1, 2021 11:05:38 GMT -5
I misunderstood...now I'm back to feeling totally inadequate about my tumbles. Well Jason, once you get the recipe to perfection I suppose it is easy to tumble. It did not come easy to for me. I had a 3 pound tumbler when 13 years old and scored well with first attempts. Even polished Apache Tears. 40 years later I started tumbling again and must have messed up a half dozen loads before dialing in. This experience was very humbling. You know you are at the right place for best advise. I'd do it right by the book till you succeed. Good luck. And Happy New Year of course ! Happy New Year to you too James. I gripe about my tumbles and cabs too much! LOL I have to remember Rome wasn't built in a day...and I'm really only a couple months into this venture (adventure)...and yes, I'm totally in the right place!
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jamesp
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Post by jamesp on Jan 1, 2021 11:06:21 GMT -5
Note pocked surface of flourite to left. No explanation for why some of the fluorite had this defect. Just a guess, but it may be due to orientation of the crystal structure to the surface being polished. Or maybe the presence of impurities. You may have it right Henry. It was mysterious. I will say that felspars seem more difficult to polish. Felspar at Mohs 6 and fluorite at Mohs 4 go figure. It might be a good idea to purchase a few tumbled fluorites and toss them in with a load of agate in polishing stages and see if they un-polish and then re-polish...The oversea folks tumble polish fluorite. I think they use powerful bowl vibes with super thick slurry. How do they do it, rock shops often sell tumble polished fluorite.
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jamesp
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Post by jamesp on Jan 1, 2021 11:13:17 GMT -5
Well Jason, once you get the recipe to perfection I suppose it is easy to tumble. It did not come easy to for me. I had a 3 pound tumbler when 13 years old and scored well with first attempts. Even polished Apache Tears. 40 years later I started tumbling again and must have messed up a half dozen loads before dialing in. This experience was very humbling. You know you are at the right place for best advise. I'd do it right by the book till you succeed. Good luck. And Happy New Year of course ! Happy New Year to you too James. I gripe about my tumbles and cabs too much! LOL I have to remember Rome wasn't built in a day...and I'm really only a couple months into this venture (adventure)...and yes, I'm totally in the right place! Time/trials/effort goes a long way. Trust me, you will be laughing at the reason for your failure one day.
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Brian
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Post by Brian on Jan 1, 2021 21:21:03 GMT -5
Those pieces turned out lovely! They almost look like some of the glass that you tumble. If you believe that the glass and fluorite alone weren't able to break down the aluminum oxide, do you think you would have any success in adding just a few pieces of harder material? In other words, how much harder material would need to be added to break the aluminum oxide down? I'm still very much in learning mode, so I'm curious what your experience would tell you. That was my question Brian . About the best ratio was 30 to 35 percent mohs 7 pea gravel with 65 to 70 percent glass using AO 220 and AO polish in the vibe. 3 days AO 220, 1 day AO polish to brilliant polish. 20 to 25% quartz gravel took twice as long to polish and the final polish seemed a bit off on occasion. 50% quartz gravel broke AO down a bit quicker and always resulted in a brilliant polish. The AO 500 and AO 1000 step was skipped meaning that the AO 220 broke down to pre-polish. This HAD to happen. Resulting in a 2 step polish using only AO 220 and AO 14,000 polish.(in my vibe, perhaps not a different vibe...) Playing devil's advocate - what if Mohs 1 talc was being run, it is doubtful Mohs 9 aluminum oxide would ever be broken down. There must be some formula saying that abrasive must be softer for softer rocks. Maybe 2 Mohs notches higher than target rocks(most tumblers do Mohs 7 rocks with Mohs 9 AO and SiC). Looking at the Mohs hardness for various abrasives, it looks like it could be possible to test that theory. If fluorite has a Mohs hardness of about 4, a search of a list of possible abrasives shows that pumice has a Mohs hardness of 6. Rottenstone is fairly easy to come by. It certainly seems reasonable that the ideal abrasive for any given material should be based on their relative hardnesses. I just did a quick search and it looks like you already explored this route: forum.rocktumblinghobby.com/thread/80576/pumice-tumble-polishing-soft-rocks. How did that experiment work out? It doesn't look like you ever reported back on that experiment. One thing I have also been curious about is the effect of density on tumbling. The density of fluorite (3.1) is closer to that of not too far from that of AO (3.9) and SiC (3.2). Agates and jaspers have a density of around 2.6. Pumice might act differently due to its very low density or the fact that it just breaks down quickly.
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jamesp
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Post by jamesp on Jan 2, 2021 4:32:25 GMT -5
That was my question Brian . About the best ratio was 30 to 35 percent mohs 7 pea gravel with 65 to 70 percent glass using AO 220 and AO polish in the vibe. 3 days AO 220, 1 day AO polish to brilliant polish. 20 to 25% quartz gravel took twice as long to polish and the final polish seemed a bit off on occasion. 50% quartz gravel broke AO down a bit quicker and always resulted in a brilliant polish. The AO 500 and AO 1000 step was skipped meaning that the AO 220 broke down to pre-polish. This HAD to happen. Resulting in a 2 step polish using only AO 220 and AO 14,000 polish.(in my vibe, perhaps not a different vibe...) Playing devil's advocate - what if Mohs 1 talc was being run, it is doubtful Mohs 9 aluminum oxide would ever be broken down. There must be some formula saying that abrasive must be softer for softer rocks. Maybe 2 Mohs notches higher than target rocks(most tumblers do Mohs 7 rocks with Mohs 9 AO and SiC). Looking at the Mohs hardness for various abrasives, it looks like it could be possible to test that theory. If fluorite has a Mohs hardness of about 4, a search of a list of possible abrasives shows that pumice has a Mohs hardness of 6. Rottenstone is fairly easy to come by. It certainly seems reasonable that the ideal abrasive for any given material should be based on their relative hardnesses. I just did a quick search and it looks like you already explored this route: forum.rocktumblinghobby.com/thread/80576/pumice-tumble-polishing-soft-rocks. How did that experiment work out? It doesn't look like you ever reported back on that experiment. One thing I have also been curious about is the effect of density on tumbling. The density of fluorite (3.1) is closer to that of not too far from that of AO (3.9) and SiC (3.2). Agates and jaspers have a density of around 2.6. Pumice might act differently due to its very low density or the fact that it just breaks down quickly. That experiment got abandoned for some reason Brian. A few quicky runs were made with no easy success. I remember trying graded pumice, graded garnet, graded quartz, diatomaceous earth and iron oxide. All of those are softer than AO and used as abrasives for various reasons. I still have the rough shaped fluorite to work with and hope to continue that experiment. Different abrasives do have different uses. SiC cuts by shattering being brittle and exposing sharp cutting edges. Aluminum oxide does not normally shatter being tough. It rounds and makes a polished surface. SiC for material removal, AO for smoothing. Not sure how pumice works. Garnet for example is tough like AO, it does not shatter but rounds. Diatomaceous earth is very porous like pumice and shatters like SiC. Both probably break down quickly. Density does play a role in tumbling. Alumina based ceramic media is about 3.9 density, Zirconia ceramic media is like 6. So a 10 pound quartz capacity hopper can hold like 24 pounds of Zirconia media. Zirconia media is used on hard metal parts in commercial vibes and known for damaging softer aluminum parts due to it's high density. Vibes can generate a deceptive amount of 'hammering' forces which is why they break abrasives down so much faster than a rotary. Increasing the density increases the hammering forces(exponentially if not mistaken). Zirconia is also tough to avoid breakage during a run. A single broken ceramic can scratch target rocks.
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Brian
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Post by Brian on Jan 5, 2021 19:31:13 GMT -5
Looking at the Mohs hardness for various abrasives, it looks like it could be possible to test that theory. If fluorite has a Mohs hardness of about 4, a search of a list of possible abrasives shows that pumice has a Mohs hardness of 6. Rottenstone is fairly easy to come by. It certainly seems reasonable that the ideal abrasive for any given material should be based on their relative hardnesses. I just did a quick search and it looks like you already explored this route: forum.rocktumblinghobby.com/thread/80576/pumice-tumble-polishing-soft-rocks. How did that experiment work out? It doesn't look like you ever reported back on that experiment. One thing I have also been curious about is the effect of density on tumbling. The density of fluorite (3.1) is closer to that of not too far from that of AO (3.9) and SiC (3.2). Agates and jaspers have a density of around 2.6. Pumice might act differently due to its very low density or the fact that it just breaks down quickly. That experiment got abandoned for some reason Brian . A few quicky runs were made with no easy success. I remember trying graded pumice, graded garnet, graded quartz, diatomaceous earth and iron oxide. All of those are softer than AO and used as abrasives for various reasons. I still have the rough shaped fluorite to work with and hope to continue that experiment. Different abrasives do have different uses. SiC cuts by shattering being brittle and exposing sharp cutting edges. Aluminum oxide does not normally shatter being tough. It rounds and makes a polished surface. SiC for material removal, AO for smoothing. Not sure how pumice works. Garnet for example is tough like AO, it does not shatter but rounds. Diatomaceous earth is very porous like pumice and shatters like SiC. Both probably break down quickly. Density does play a role in tumbling. Alumina based ceramic media is about 3.9 density, Zirconia ceramic media is like 6. So a 10 pound quartz capacity hopper can hold like 24 pounds of Zirconia media. Zirconia media is used on hard metal parts in commercial vibes and known for damaging softer aluminum parts due to it's high density. Vibes can generate a deceptive amount of 'hammering' forces which is why they break abrasives down so much faster than a rotary. Increasing the density increases the hammering forces(exponentially if not mistaken). Zirconia is also tough to avoid breakage during a run. A single broken ceramic can scratch target rocks. I'm certainly curious to see what would happen if you try out the fluorite/pumice experiment again. The question of what pumice does has been occupying my gray cells a lot over the past couple days. I went to the trade school right up the road from you, so I am always getting lost in these little thought experiments. I've lost track of number of variables that I imagine would impact the ability of an abrasive to provide the right level of polish. I definitely need to do some more research on crystal structures and fracture patterns before I lose much more sleep over this. I really have a hard time imagining pumice surviving long enough to really accomplish much of anything. I've used pumice as an abrasive for cleaning and polishing wood, and it seems to break down extremely quick. It's low density also seems like it would pose problems. I keep thinking about what it would like like within a tumbler and I imagine it "floating" around and squirting about between stones sort of like trying to pick out a piece of dust from water with your fingers. It seems like the denser water would push away the pumice. I have a large bag of diatomaceous earth sitting around, but would not have considered using that as an abrasive either.
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jamesp
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Post by jamesp on Jan 6, 2021 6:52:59 GMT -5
Far out brian. Did you go to Ga Tech ? I have a BSME from there and have been cursed with brain storms ever since. Not many subjects are allowed to be simple lol. It's a curse ! Comparing pumice to silicon carbide(diatomaceous earth included): Both are brittle and crush or breakdown. Suggesting that both stay sharp for most of their life as an abrasive. Also suggesting they are probably poor polishing abrasives. Diatomaceous earth and pumice are both totally porous. My findings with silicon carbide breakdown rate when tumbling Mohs 7 stones in a rotary: In a small 3 pound tumbler it breaks down slow. It simply lacks enough weight in rocks to break it down quickly. In an 8 inch barrel rotating slow breakdown is faster. Simply more weight and therefore crushing ability. If you really want fast SiC breakdown spin a 6 to 8 inch barrel faster. Speed is the trick for fast shaping. Speed with consequences. Low viscosity water slurry seems to crush SiC and is not as efficient at cutting rocks at higher speeds due to the slamming impact action(rattling and klanking sounds emanate from barrel). However if you add a slurry thickener rock cutting occurs faster and fast breakdown occurs both at the same time. The thickener creates more of a rubbing effect between rocks.(sounds like a steady grinding sound from barrel). A great pumice test would be to dose a load of freshly broken soapstone with a dose of coarse pumice in the rotary and see if the soapstone rounds off. If it does then step up to Mohs 3 calcite and do the same run. If it rounds off then step up to fluorite and see if pumice can round it off. Pumice abrasive stuck to an abrasive pad for finishing glass(take note tumbling is very different than lapping): "Pumice can be a very versatile abrasive for use with glass. Unlike loose abrasive like silicon carbide or aluminum oxide, pumice is a very friable abrasive that allows you to achieve a very fine surface grind on your glass. It can be used to give a pre-polish finish on your glass from a fine grit surface or even achieve a near polish on your glass without the use of cerium. Pumice can be used with a brush wheel or MJ wheel on a lathe, it can be used by hand with a Scotch-brite pad, it can be used with a cork belt on an upright belt sander, and it can be used with a felt pad or cork pad on a flat lap grinder as well. It's a highly versatile abrasive that can be utilized with virtually every type of cold working equipment." This link will explain pumice as used on glass as a lapping operation clearly. I bought my graded pumice from this fellow. www.hisglassworks.com/support/loose-abrasives/using-pumice-on-your-glass.htmlHowever I use SiC and AO exclusively when tumbling glass. Examples: www.flickr.com/photos/67205364@N06/sets/72157689895637020
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Brian
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Post by Brian on Jan 6, 2021 21:34:36 GMT -5
Far out brian . Did you go to Ga Tech ? I have a BSME from there and have been cursed with brain storms ever since. Not many subjects are allowed to be simple lol. It's a curse ! Comparing pumice to silicon carbide(diatomaceous earth included): Both are brittle and crush or breakdown. Suggesting that both stay sharp for most of their life as an abrasive. Also suggesting they are probably poor polishing abrasives. Diatomaceous earth and pumice are both totally porous. My findings with silicon carbide breakdown rate when tumbling Mohs 7 stones in a rotary: In a small 3 pound tumbler it breaks down slow. It simply lacks enough weight in rocks to break it down quickly. In an 8 inch barrel rotating slow breakdown is faster. Simply more weight and therefore crushing ability. If you really want fast SiC breakdown spin a 6 to 8 inch barrel faster. Speed is the trick for fast shaping. Speed with consequences. Low viscosity water slurry seems to crush SiC and is not as efficient at cutting rocks at higher speeds due to the slamming impact action(rattling and klanking sounds emanate from barrel). However if you add a slurry thickener rock cutting occurs faster and fast breakdown occurs both at the same time. The thickener creates more of a rubbing effect between rocks.(sounds like a steady grinding sound from barrel). A great pumice test would be to dose a load of freshly broken soapstone with a dose of coarse pumice in the rotary and see if the soapstone rounds off. If it does then step up to Mohs 3 calcite and do the same run. If it rounds off then step up to fluorite and see if pumice can round it off. Pumice abrasive stuck to an abrasive pad for finishing glass(take note tumbling is very different than lapping): "Pumice can be a very versatile abrasive for use with glass. Unlike loose abrasive like silicon carbide or aluminum oxide, pumice is a very friable abrasive that allows you to achieve a very fine surface grind on your glass. It can be used to give a pre-polish finish on your glass from a fine grit surface or even achieve a near polish on your glass without the use of cerium. Pumice can be used with a brush wheel or MJ wheel on a lathe, it can be used by hand with a Scotch-brite pad, it can be used with a cork belt on an upright belt sander, and it can be used with a felt pad or cork pad on a flat lap grinder as well. It's a highly versatile abrasive that can be utilized with virtually every type of cold working equipment." This link will explain pumice as used on glass as a lapping operation clearly. I bought my graded pumice from this fellow. www.hisglassworks.com/support/loose-abrasives/using-pumice-on-your-glass.htmlHowever I use SiC and AO exclusively when tumbling glass. Examples: www.flickr.com/photos/67205364@N06/sets/72157689895637020Great to meet a fellow Tech alum, jamesp! I did my undergrad in chemical engineering, and, glutton for punishment that I am, went back for a degree in chemistry. I clearly needed to do more brainstorming. If pumice is anything like SiC, then it may be possible to improve results using a small tumbler with a thicker slurry. The thicker slurry should help slow the movement of the pumice so that it doesn't "float" too much and the smaller barrel should help minimize breakage of the pumice by decreasing the distance the rocks are tumbling. It also seems like using more pumice than you would typically use for SiC may also help by simply increasing the number of particles that can make contact with the rocks before breaking down. I have my eye on some softer rocks, so the pumice experiment you laid out certainly seems like one worth trying. I've read several different approaches for working with those softer rocks, but it sounds like it is still a challenge to get good results.
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