cosmetal
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Post by cosmetal on Feb 20, 2019 11:50:05 GMT -5
Hi, all.
It's my understanding that most bentonite based clays will contain between 1% to 5% silica.
Has anyone ever had problems with scratches if you use a bentonite based clay/viscosifier in AO pre-polish and AO polish?
Thanks! James
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RWA3006
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Post by RWA3006 on Feb 20, 2019 18:18:41 GMT -5
I guess we could find out. When the snow melts in Wyoming I'll get some bentonite from the badlands and send a flat rate box to anyone who wants to try it if they will just pay shipping.
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pizzano
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Post by pizzano on Feb 20, 2019 20:22:09 GMT -5
Hi, all. It's my understanding that most bentonite based clays will contain between 1% to 5% silica. Has anyone ever had problems with scratches if you use a bentonite based clay/viscosifier in AO pre-polish and AO polish? Thanks! James I bowl vibe everything now after rotary.......never use thickeners for pre-polish and polish stages..........I've also rotary polished quite a bit, never used thickeners then either.
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Post by pauls on Feb 20, 2019 21:10:01 GMT -5
I wouldn't worry about the silica in your coarse stages, if your grinding is working properly you should end up with a lot more silica than that in your slurry from off the corners of your rocks. Probably not a good idea in prepolish and polish though
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El JeffA
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Post by El JeffA on Feb 20, 2019 21:13:02 GMT -5
I was having a problem with my Lot-O prepolish and polish after a year or so of success. I knew it had to be something I was doing wrong! I discovered that there were tiny pieces of quartz in my ceramic media that I had run in earlier stages with cat litter to soften the edges. I separated, cleaned and inspected the ceramic media and no longer run any with cat litter. The small quartz was clear and tiny. Quite hard to see at my age without some kind of magnification...in my case, just reading glasses. Hope this helps and good luck! Jeff A
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Post by vegasjames on Feb 20, 2019 21:23:44 GMT -5
I guess we could find out. When the snow melts in Wyoming I'll get some bentonite from the badlands and send a flat rate box to anyone who wants to try it if they will just pay shipping. I am definitely interested in some of the bentonite for an experiment I have been working on. Let me know when you get some. Thanks.
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Post by vegasjames on Feb 20, 2019 21:31:33 GMT -5
Hi, all. It's my understanding that most bentonite based clays will contain between 1% to 5% silica. Has anyone ever had problems with scratches if you use a bentonite based clay/viscosifier in AO pre-polish and AO polish? Thanks! James Just because it contains silica that would not mean it is necessarily highly abrasive. Same for the aluminum oxide content. Diatomaceous earth for example is 80% silica and 10 % metal oxides including aluminum oxide yet only has a hardness of 1-1.5 on average but can be as hard as 5, which is still softer than most rocks being tumbled.
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RWA3006
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Post by RWA3006 on Feb 20, 2019 22:39:16 GMT -5
I guess we could find out. When the snow melts in Wyoming I'll get some bentonite from the badlands and send a flat rate box to anyone who wants to try it if they will just pay shipping. I am definitely interested in some of the bentonite for an experiment I have been working on. Let me know when you get some. Thanks. I'll send you some as soon as I get over there when it dries out. There's plenty of deposits that appear to be highly refined and I think there's some great potential. The badlands East of the Bridger Valley are full of the stuff.
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jamesp
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Post by jamesp on Feb 21, 2019 9:04:01 GMT -5
Hi, all. It's my understanding that most bentonite based clays will contain between 1% to 5% silica. Has anyone ever had problems with scratches if you use a bentonite based clay/viscosifier in AO pre-polish and AO polish? Thanks! James Interesting question cosmetal. It is likely that bentonite is refined to remove silica since silica is now viewed as a carcinogen. Bentonite is constantly handled by well drillers and heavy equipment operators when spreading bentonite for sealing pond bottoms so they are all susceptible. Might be best to use bentonite in a tumbler already pre-wetted/pre-expanded since it expands so much when dry. Processed kaolin clay is often processed down to less than 1% silica. Agricultural lime is often processed down to less than 1% silica. Both make great slurries but the lime is way to alkaline and will cook your hands. Personally I would avoid clay slurries due to concern for sand particles when tumbling with abrasives finer than 500 grit. I tried AO 14,000 in a rotary on several attempts with unrefined kaolin clay(about 30% silica sand composition) and never attained polish. Side note, bentonite like kaolin is a colloidal clay. Colloidal clays make the best suspension agents: "Sodium bentonite[edit] Sodium bentonite expands when wet, absorbing as much as several times its dry mass in water. Because of its excellent colloidal properties,[4] it is often used in drilling mud for oil and gas wells and boreholes for geotechnical and environmental investigations.[3]" Wikipedia PS welcome to the forum
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jamesp
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Post by jamesp on Feb 21, 2019 10:22:05 GMT -5
Hi, all. It's my understanding that most bentonite based clays will contain between 1% to 5% silica. Has anyone ever had problems with scratches if you use a bentonite based clay/viscosifier in AO pre-polish and AO polish? Thanks! James Just because it contains silica that would not mean it is necessarily highly abrasive. Same for the aluminum oxide content. Diatomaceous earth for example is 80% silica and 10 % metal oxides including aluminum oxide yet only has a hardness of 1-1.5 on average but can be as hard as 5, which is still softer than most rocks being tumbled. Not sure why James but when using alum oxide rich kaolin from nature with about 30% sand content I had problems getting a polish in a rotary. So I limited the use of unrefined clay to abrasives with grit sizes 500 and less. Could it be the alum ox felspar particles that kaolin is made up of that prevented polish ? Not having refined clay I resorted to sugar for a thickener/carrier for pre-polish and polishing in both rotary and vibe. pizzano, I have no choice but to use a thickener with glass and obsidian in the vibe. Or else it will frost. Lot-O or Vibrasonic. The sugar dissolves therefore releasing compacted alum ox in the tumbles when washed with warm/hot water since sugar dissolves. You might understand opalized (?) silica. It apparently has a Mohs hardness of 6 or less. Diatomaceous earth is opalized silica if not mistaken. Diatomaceous earth had little effect when run as a polish or pre-polish on glass which puzzled me. Pumice silica might be opalized too It is used on wheels to pre-polish glass. Maybe polish too.
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cosmetal
starting to spend too much on rocks
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Post by cosmetal on Feb 21, 2019 11:32:10 GMT -5
Thanks, all, for the very informative answers.
Let me ask a very direct question:
Has anyone ever used Old Miser in their pre-polish or polish stages? Your results. please?
Peace, James
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Post by vegasjames on Feb 21, 2019 22:19:13 GMT -5
Just because it contains silica that would not mean it is necessarily highly abrasive. Same for the aluminum oxide content. Diatomaceous earth for example is 80% silica and 10 % metal oxides including aluminum oxide yet only has a hardness of 1-1.5 on average but can be as hard as 5, which is still softer than most rocks being tumbled. Not sure why James but when using alum oxide rich kaolin from nature with about 30% sand content I had problems getting a polish in a rotary. So I limited the use of unrefined clay to abrasives with grit sizes 500 and less. Could it be the alum ox felspar particles that kaolin is made up of that prevented polish ? Not having refined clay I resorted to sugar for a thickener/carrier for pre-polish and polishing in both rotary and vibe. pizzano , I have no choice but to use a thickener with glass and obsidian in the vibe. Or else it will frost. Lot-O or Vibrasonic. The sugar dissolves therefore releasing compacted alum ox in the tumbles when washed with warm/hot water since sugar dissolves. You might understand opalized (?) silica. It apparently has a Mohs hardness of 6 or less. Diatomaceous earth is opalized silica if not mistaken. Diatomaceous earth had little effect when run as a polish or pre-polish on glass which puzzled me. Pumice silica might be opalized too It is used on wheels to pre-polish glass. Maybe polish too. There is a good point there in the fact that silica can take on many forms and thus have different hardnesses.
I think other factors would include sharpness of edges and particle size.
Diatomaceous earth is the skeletal remains of diatoms, and I have heard is opalized. But have also heard that it is a source of silica for some opal formation.
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jamesp
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Post by jamesp on Feb 22, 2019 8:28:17 GMT -5
vegasjames maybe you can figure silica out with your brilliant chemistry mind. Botryoidal(opalized) quartz's, glass/obsidian, chert, silicified fossils, chert, crystalline and cryptocrystalline(agates) quartz make up 95% ? of commonly tumbled rocks. Chalcedony fits in there somewhere. And then there is opalized? silica found in bamboo, horse tail, rice seed, psyllium etc which are some kind of inorganic silica ? I suspect sharpness and grain size of common crystalline quartz sand is going to be the culprit in preventing a polish when using a clay slurry because it is the most common large hard particle contaminant in clay. A call to Covington Engineering would probably explain the composition of Old Miser for use as a polishing slurry. Old Miser is probably Montmorillonite clay and is similar to bentonite. Origination and composition of common clay in English: www.tulane.edu/~sanelson/eens211/weathering&clayminerals.htmFelspar is the most common clay mineral. I don't think quartz is considered a clay mineral. Source of most clay is granite and basalt. Felspar breaks down to tiny platelets creating the best suspension clay of all clays, colloidal clays. If you tumble felspar you would likely get a colloidal clay slurry.
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Post by vegasjames on Feb 22, 2019 19:30:24 GMT -5
vegasjames maybe you can figure silica out with your brilliant chemistry mind. Botryoidal(opalized) quartz's, glass/obsidian, chert, silicified fossils, chert, crystalline and cryptocrystalline(agates) quartz make up 95% ? of commonly tumbled rocks. Chalcedony fits in there somewhere. And then there is opalized? silica found in bamboo, horse tail, rice seed, psyllium etc which are some kind of inorganic silica ? I suspect sharpness and grain size of common crystalline quartz sand is going to be the culprit in preventing a polish when using a clay slurry because it is the most common large hard particle contaminant in clay. A call to Covington Engineering would probably explain the composition of Old Miser for use as a polishing slurry. Old Miser is probably Montmorillonite clay and is similar to bentonite. Origination and composition of common clay in English: www.tulane.edu/~sanelson/eens211/weathering&clayminerals.htmFelspar is the most common clay mineral. I don't think quartz is considered a clay mineral. Source of most clay is granite and basalt. Felspar breaks down to tiny platelets creating the best suspension clay of all clays, colloidal clays. If you tumble felspar you would likely get a colloidal clay slurry. There are still other forms of silica such as tridymite, cristobalite and coesite.
The form of silica in bamboo is more likely orthosilicic acid. When injured the bamboo can secrete a "sap" that is rich in this which condenses forming small nodules of opal. I suspect the silica in horsetail, rice bran and psyllium would be similar as plants uptake silica as orthosilciic acid. Same or humans, which absorb and utilize silica as orthosilicic acid. Few plants actually produce opal that I am aware of as part of their natural structure. The tips of stinging nettle for example are opalized to keep them sharp.
Animals can also form opal. The stingers of bees for example are opalized as well to keep them sharp.
As far as I know the main sources for silica to form opal in rock are the feldspars, which also provide the aluminum oxide found in opals (2-5%), and sandstone.
That being said of course there are the two main classes of opal common and precious. So what is the difference? Common opal and precious opal are both composed of silica spheres. In common opal though the sphere sizes tend to be larger and are very disordered in arrangement. Precious opal has smaller spheres 150-300nmin size in a ordered arrangement that gives the opal its play of color.
This brings up the the other thing involved which is bringing the silica molecules down to size. This is part from weathering or other natural breakdown by natural grinding and also involves some chemical processes. This is why not all "opal dirt" forms precious opal. You can obtain both common and precious opal from the same exact opal dirt. The finer ground particles will form their own layer and can form in to precious opal while the larger particles can form common opal. More than likely the Old Miser is composed of a betonite, which is composed mainly of montmorillonite, that has been ground to a finer mesh. There is a betonite that you can buy that has been ground a really fine 400 mesh as opposed to most of the commercial betonite that is around 325 mesh or larger. The additional grinding will not only make the particles finer but will also smooth out sharp edges just like tumbling rocks. I have looked in to the stuff in the past and it is considerably more expensive than the 325 mesh. 10 pounds of the 325 mesh is around $5 as where 10 pounds of the 400 mesh is around $75.
Note there are also different types of bentonite with calcium betonite and sodium betonite being the primary forms. Calcium betonite is the stuff you normally see being sold for cosmetics and some people take for "detoxing". Sodium betonite expands greatly in water and therefore is used more in industry for things like drilling for oil. If trying to cushion rocks it makes more sense to use small amounts of the sodium bentonite.
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jamesp
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Post by jamesp on Feb 23, 2019 7:37:07 GMT -5
Thanks for this information vegasjames. I followed you well and you put this subject of silica in laymen's terms. Thanks again. 'The form' of silica is a complicated subject. In the case of orthosilicic acid it is a compound. Not being a chemist I look up quartz SiO2 on Wikipedia and get this statement "Quartz is a mineral composed of silicon and oxygen atoms in a continuous framework of SiO4 silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical formula of SiO2. Quartz is the second most abundant mineral in Earth's continental crust, behind feldspar.[7]" But reading about quartz on Wikipedia further the simple formula SiO2 gets real complicated with all kinds of chemical terminology and greek alphabets lol. I want to leave this subject to the experts. On the subject of sand free clay, dried up silt catchment ponds in clay rich locations are a good source. Especially at construction sites where catchment ponds are required to prevent silt run-off into natural waterways. The colloidal clay particles simply settle to the bottom much slower than sand particles leaving these slabs of pure clay. The deeper the pond the more time for large/heavy particle separation. Example of a dried up silt catchment pond: This is a small 6' X 12' catchment pond at a construction site close to my home. There was about 300-400(about $2500 worth of Old Miser) pounds of pure clay plates available in this little pond at this summer dry down. The site developer had about a dozen small catchments like this on the site. I tested for particles by briskly mixing samples in a large glass jar, letting it settle 30 minutes, then poured the muddy water off. It passed particle free.
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Post by Rockindad on Feb 25, 2019 20:48:46 GMT -5
Thanks for this information vegasjames . I followed you well and you put this subject of silica in laymen's terms. Thanks again. 'The form' of silica is a complicated subject. In the case of orthosilicic acid it is a compound. Not being a chemist I look up quartz SiO2 on Wikipedia and get this statement "Quartz is a mineral composed of silicon and oxygen atoms in a continuous framework of SiO4 silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical formula of SiO2. Quartz is the second most abundant mineral in Earth's continental crust, behind feldspar.[7]" But reading about quartz on Wikipedia further the simple formula SiO2 gets real complicated with all kinds of chemical terminology and greek alphabets lol. I want to leave this subject to the experts. On the subject of sand free clay, dried up silt catchment ponds in clay rich locations are a good source. Especially at construction sites where catchment ponds are required to prevent silt run-off into natural waterways. The colloidal clay particles simply settle to the bottom much slower than sand particles leaving these slabs of pure clay. The deeper the pond the more time for large/heavy particle separation. Example of a dried up silt catchment pond: This is a small 6' X 12' catchment pond at a construction site close to my home. There was about 300-400(about $2500 worth of Old Miser) pounds of pure clay plates available in this little pond at this summer dry down. The site developer had about a dozen small catchments like this on the site. I tested for particles by briskly mixing samples in a large glass jar, letting it settle 30 minutes, then poured the muddy water off. It passed particle free. You could have a nice little side business there. "James P's Slurry Starter". You could probably sell out on this forum alone! Al
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jamesp
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Post by jamesp on Feb 26, 2019 4:19:28 GMT -5
Interesting sideline business Rockindad. The red clay does work better as a slurry additive than the white version. Looks like some one has a monopoly on the clay in this neighborhood: Kaolin Capital of the World www.sandersville.net/KaolinCapitaloftheWorld.cfmSandersville is known as the “Kaolin Capital of the World.” One of Georgia’s most important minerals, kaolin is a white, alumina-silicate clay used in hundreds of products ranging from paper to cosmetics to the nose cones of rockets. Kaolin is also used in medicines, paints and many other products, all of which are shipped around the world. At the end of the 20th century, kaolin was an $800 million business and Georgia's largest volume export. Mining companies have reclaimed and restored more than 80 percent of the land that has been stripped since 1969. About 2.5 million tons of kaolin is shipped annually from Georgia's "white gold" belt in 13 counties along the fall line that girdles the mid-portion of the state. Mineralogists say that 50 to 100 million years ago, particles of kaolin or aluminum silicate were washed down from the rocky piedmont hills, coming to rest at the edge of a shallow sea, marked today by the fall line. Fragments of fossilized shark's teeth and shells hint at the clay's origin near the shore of the prehistoric sea. More - www.georgiaencyclopedia.org/articles/business-economy/kaolin
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Post by vegasjames on Feb 26, 2019 6:49:40 GMT -5
Interesting sideline business Rockindad . The red clay does work better as a slurry additive than the white version. Looks like some one has a monopoly on the clay in this neighborhood: Kaolin Capital of the World www.sandersville.net/KaolinCapitaloftheWorld.cfmSandersville is known as the “Kaolin Capital of the World.” One of Georgia’s most important minerals, kaolin is a white, alumina-silicate clay used in hundreds of products ranging from paper to cosmetics to the nose cones of rockets. Kaolin is also used in medicines, paints and many other products, all of which are shipped around the world. At the end of the 20th century, kaolin was an $800 million business and Georgia's largest volume export. Mining companies have reclaimed and restored more than 80 percent of the land that has been stripped since 1969. About 2.5 million tons of kaolin is shipped annually from Georgia's "white gold" belt in 13 counties along the fall line that girdles the mid-portion of the state. Mineralogists say that 50 to 100 million years ago, particles of kaolin or aluminum silicate were washed down from the rocky piedmont hills, coming to rest at the edge of a shallow sea, marked today by the fall line. Fragments of fossilized shark's teeth and shells hint at the clay's origin near the shore of the prehistoric sea. More - www.georgiaencyclopedia.org/articles/business-economy/kaolinI get a lot of red clay from washing the red selenite crystals I mine. They are found in a laterite layer of red mud that is almost as hard as concrete when dry. Once wetted it rapidly turns mushy. I have not had the mud tested to determine the type of mud or its composition but have thrown some of it in the tumbler barrels for cushioning when I am tumbling rocks to clean them or to soften their edges. Sometimes I will also throw some of the broken selenite crystals in there as well and let them grind down. Does seem to work well.
When I wash the crystals that are encased in the mud I let the mud settle out in a tub then pour off as much water as possible then let it dry out. Been playing with it in various experiments trying to find more uses for the stuff since I end up with so much of it.
You can see the laterite layer in this photo. It is the bottom layer. All those lumps sticking out are red selenite crystals.
The rocky layer above the laterite layer is ancient shoreline and is composed of cemented rounded pebbles. The layer above that is another layer with low quality selenite crystals and the top layer is composed of soil mainly made up of decomposed gypsum and some dirt.
These are examples of the crystals.
And they polish up really nice.
I suspect that the clay is going to be fairly low in silica as the crystals form in a liquid medium so heavier particles such as sand particles should have settled out in the liquid before the crystals would have grown.
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jamesp
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Post by jamesp on Feb 26, 2019 7:20:38 GMT -5
I would use the clay in the 2 dark red layers as a slurry thickener without hesitation with coarse silicon carbide and SiC 220-500 steps also vegasjames. The only clay in N.Georgia is about all derived from our monoculture of quartz and felspar rich granite being eroded by the environment. Soft minerals like selenium and gypsum rarely happen around here. There are barite and soapstone deposits in the mountains 100 miles north. Some of the soapstone plates can be 2 inches thick and yellow/green yet still pass light. Beautiful and of high quality. The iron stains on/in your selenite crystals are a common site in our crystalline quartz. This is an iron stained clay James ? One reason I ask is that iron rich red kaolin clay makes a much better tumbling slurry than the lily white kaolin. Have you hand polished those selenium crystals ?
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Post by vegasjames on Feb 26, 2019 10:01:17 GMT -5
I would use the clay in the 2 dark red layers as a slurry thickener without hesitation with coarse silicon carbide and SiC 220-500 steps also vegasjames . The only clay in N.Georgia is about all derived from our monoculture of quartz and felspar rich granite being eroded by the environment. Soft minerals like selenium and gypsum rarely happen around here. There are barite and soapstone deposits in the mountains 100 miles north. Some of the soapstone plates can be 2 inches thick and yellow/green yet still pass light. Beautiful and of high quality. The iron stains on/in your selenite crystals are a common site in our crystalline quartz. This is an iron stained clay James ? One reason I ask is that iron rich red kaolin clay makes a much better tumbling slurry than the lily white kaolin. Have you hand polished those selenium crystals ? The clay does contain a lot of iron. The laterite formed by the oxidation of pyrite. When the rain reacts with the oxidized iron pyrite sulfuric acid and iron hydroxide are formed. These trickled down to the limestone (calcium carbonate) layer of our ancient seabed where the sulfuric acid reacted forming calcium sulfate that crystallized as selenite crystals. The iron hydroxide was converted in to iron oxide creating the red mud and red selenite. Someday I may actually get an analysis done on the mud to find out whatever else is in it. I still doubt it has much silica as that would have mostly settled out during the liquid phase when the crystals were growing. The only silica would be from any silicic acids that may have formed in to amorphous silica.
Most of the selenite was polished on a Genie. The trick is to gently round off the sharp edges to keep the wheels from catching the edges of the plates and splitting the crystals. And not to be aggressive in grinding. When finished with the wheels buff with Zam and they come out great with rainbows and shimmering effects in the layers.
The pointed crystal shaped ones were broken crystals I shaped with a flat lap to make the sides then angled for the points. Great way to utilize the damaged crystals.
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