jamesp
Cave Dweller
Member since October 2012
Posts: 36,155
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Post by jamesp on May 25, 2015 11:22:32 GMT -5
Getting ready to roll some coral chips. To chip off the sharp edges two larger rocks are put in barrel. Barrel half full for more violent tumble. Not much water, say 2 inches below rocks. No grit. 3-4 days. Gets rid of wimpy edges that may chip off later in the tumble. Two large rocks about 6 and 9 ounces. Barrel is 14 pounder. Works with coral and most tough agates, not softer rocks. Volume reduces rapidly, so more rocks added every day or two. Again, agate and coral rarely frost so method has worked well on these materials.
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Post by paulshiroma on May 25, 2015 19:58:36 GMT -5
Looking forward to following this one.
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,155
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Post by jamesp on May 25, 2015 22:05:05 GMT -5
Looking forward to following this one. Been doing the sharp edge removal for years Paul. Usually with a few big rocks in the barrel. This batch had no large pieces so two were added.
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Fossilman
Cave Dweller
Member since January 2009
Posts: 20,681
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Post by Fossilman on May 25, 2015 22:11:09 GMT -5
Great idea!!!!!!
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grizman
freely admits to licking rocks
Member since July 2011
Posts: 878
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Post by grizman on May 25, 2015 22:21:21 GMT -5
Will you please show us how the progression goes as you get them ready for the polishing stage?
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,155
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Post by jamesp on May 26, 2015 6:46:57 GMT -5
Will you please show us how the progression goes as you get them ready for the polishing stage? Last batch grizman, paulshiroma, before and after, edges knocked off these with larger rocks at beginning 3-4 days: Before: After: End product had no fractures or frosting. But after 3-4 days the edges were chipped and jagged in the initial ball milling process. And tumbler was full of small splinters, that may have splintered off later in the tumble. and the amount of splinters is significant. For size comparison. upper photo is 26 inches across, lower photo is 13 inches across. So you can kinda figure the size reduction.
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,155
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Post by jamesp on May 27, 2015 18:00:19 GMT -5
After a couple of days barrel is 20% of original rock height. Added more sharp rock. Top rock has sharp edges removed, bottom rock not ball milled with sharp edges. not ball milled: after ball milled:
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Post by Pat on May 27, 2015 20:28:40 GMT -5
What does "ball mill" mean?
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,155
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Post by jamesp on May 28, 2015 4:25:08 GMT -5
Pat A ball mill is a way to crush materials in a rotating drum full of steel or agate balls. Later in this video at about 6:00 you can see the balls crushing glass. Used to make talc powder from talc for instance. Enjoy dastardly quasi-Steppenwolf background music .
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