zekester55
starting to spend too much on rocks
Member since March 2017
Posts: 111
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Post by zekester55 on Apr 15, 2017 10:01:04 GMT -5
Received a packet of this with something else I purchased, said to help the grit cling to the stone in slurry. Anyone here know what exactly this material is made of? Do you use it? have you had success with it, does it make a difference?
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Post by Pat on Apr 15, 2017 10:34:12 GMT -5
Photo would be helpful ; )
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Post by johnjsgems on Apr 15, 2017 10:40:43 GMT -5
Covington Engineering sells it. Never tried it myself.
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zekester55
starting to spend too much on rocks
Member since March 2017
Posts: 111
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Post by zekester55 on Apr 17, 2017 6:16:52 GMT -5
A little further web research uncovered this:
"Covington's Old Miser (R) comes in a 12 oz bag. Covington recommends 4-teaspoons of Old Miser(R) per 1 pound of grit. (Note: Do not use Old Miser (R) during the polishing stage.) Detailed instructions from Covington are included in your sample order of Old Miser Grit Carrier stating, Old Miser(R) is great for faster lapping, tumbling, and sphere cutting. It holds grit to your work so that it isn't thrown off by centrifugal force or washed away by the small amount of water used in your work. Assists by quickly making a slurry and holding grit to stone thereby speeding up the process and saving grit. However, it is water-soluble and washes off the specimen easily. Old Miser(R) pays for its cost many times over in grit and time saved. During the tumbling process, it holds the grit in suspension so that all the rocks are always covered with the grit for faster grinding. Old Miser(R) doesn't allow the water to wash the grit to the bottom of the tumbler, etc. R. Ritchie, ME, a sphere cutter, was kind enough to send more info on "Old Grit Miser", or GM abbreviation. "GM is a powder that looks like cocoa. Its purpose is to maintain the grit in a thick suspension especially when the stone being worked doesn't make mud of its own. Hard stuff like agate doesn't and since it cuts more slowly, the stone flour is washed away with the grit. With marble, dolomite, serpentine and the like, none is needed since it cuts so quickly it makes its own goop. Particles of 90 grit are dense enough that they gravitate down and off the spinning stone to be lost. The GM makes the surface goopy enough to hold the grit for a while. It doesn't take much GM to do the job. I make up a separate commercial squeeze-bottle with a ready-to-use GM slurry for immediate use when needed. When I make up a slurry of grit #90 to #600, I add about +/- a teaspoon of GM to a half bottle of grit and water. That's an 8 ounce bottle of the kind you can get at any Wal-Mart or grocery store. I buy a package of 10 when I do. A feature of GM is that it retains a huge amount of water for its weight. I suspect it is Bentonite. So when a bottle of slurry is being made up, add enough grit for a half bottles worth of slurry (more than a half-bottle gets messy on delivery) and then add the GM. Then add the water to half full and let it sit for at least an hour. The reason being that the first addition of water is sucked into the GM to form a paste like peanut butter so when it has drunk its fill, more water has to be added."
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cosmetal
starting to spend too much on rocks
Member since September 2018
Posts: 115
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Post by cosmetal on Feb 19, 2019 19:04:51 GMT -5
If it is bentonite clay-based, I believe that it will contain 1% to 5% silica. Has anyone ever had problems with scratches if you use it in AO pre-polish and AO polish?
Also, I guess Covington doesn't ship it with an SDS (safety data sheet) which is what the old MSDS (material safety data sheet) is now called. Too bad, it would have listed all its components and %s.
Peace, James
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gatorflash1
spending too much on rocks
Active in Delaware Mineralogical Society, Cabchon Grinding and Polishing, 2 Thumlers B's and a UV-18
Member since October 2018
Posts: 375
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Post by gatorflash1 on Feb 20, 2019 9:00:46 GMT -5
If they told us they would have to kill us.
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harrym
having dreams about rocks
NH - The Granite State
Member since January 2019
Posts: 59
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Post by harrym on Feb 23, 2019 8:08:41 GMT -5
Here's a video put out by the company. The video is not specifically dedicated to Old Miser, but it does tell you how to use it - basically 4-1 mix, grit to Old Miser. Not for the polishing stages. They do make a nice looking tumbler, but way on the pricey side.
Link:
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,154
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Post by jamesp on Feb 24, 2019 6:39:53 GMT -5
Old Miser is basically bentonite clay. This is similar clay from my backyard. Some use kitty litter, it is usually fired clay. I only use clay as a grit carrier in step 1 and step 2 to jump start a slurry. About 15 minutes after adding clay and SiC 60, Old Miser should look similar: Note equal 60 grit distribution on side of barrel minutes after start up:
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goldminer
off to a rocking start
Member since March 2018
Posts: 17
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Post by goldminer on Mar 11, 2019 20:14:55 GMT -5
Received a packet of this with something else I purchased, said to help the grit cling to the stone in slurry. Anyone here know what exactly this material is made of? Do you use it? have you had success with it, does it make a difference? Yes I have used that stuff for a while now. I believe it to be some kind of dry, ground clay. When mixed with water it is a little oily which causes the grit to stay in suspension. I don't use as much as they call for and I only use it in my grinding stage although it probably could be used in the other stages.
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