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Post by perkins17 on Jul 23, 2021 14:17:24 GMT -5
I have the lortone 33b tumbler and one barrel currently has agates, jasper, maybe some petrified wood, and some small amethyst. All of these materials have very rough surfaces and will need to be tumbled for a while. Do you have to add new grit after every week? Thanks!
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Post by Drummond Island Rocks on Jul 23, 2021 14:21:55 GMT -5
Yes the grit only lasts one week before needing to be replaced.
Chuck
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Post by perkins17 on Jul 23, 2021 14:26:59 GMT -5
Ok thanks. I will be recharging this Monday.
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Post by Starguy on Jul 23, 2021 18:44:29 GMT -5
perkins17 The grit breaks down into finer grit. I recently left my 12 pounder run for over three weeks. When I opened it, the stones were semi-polished. Most of them went back in coarse for other issues. I still keep looking in my “to fine” bucket and see the ones from that batch. I think others on here have experimented with letting rocks run for longer periods with only one charge of coarse grit. I’m not sure what their results were like. Just sharing my $0.02. After a week their not running in coarse grit anymore though. Very little shaping or grinding after five to seven days. It’s amazing that a tumbler can break down carborundum which is essentially hardness 9.25 but they sure do. I think mohs is a logarithmic scale of hardness which would indicate that diamond at 10 is significantly harder than corundum at 9. To me this is proven out by how easily diamond equipment grinds corundum. When I was grinding corundum on carborundum wheels, I remember trying to decide whether the wheels were doing the most grinding or whether the corundum was.
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Post by perkins17 on Jul 23, 2021 18:51:08 GMT -5
perkins17 The grit breaks down into finer grit. I recently left my 12 pounder run for over three weeks. When I opened it, the stones were semi-polished. Most of them went back in coarse for other issues. I still keep looking in my “to fine” bucket and see the ones from that batch. I think others on here have experimented with letting rocks run for longer periods with only one charge of coarse grit. I’m not sure what their results were like. Just sharing my $0.02. After a week their not running in coarse grit anymore though. Very little shaping or grinding after five to seven days. It’s amazing that a tumbler can break down carborundum which is essentially hardness 9.25 but they sure do. Thanks for the input. That makes a lot of sense.
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rrod
having dreams about rocks
Member since December 2020
Posts: 72
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Post by rrod on Jul 23, 2021 21:13:32 GMT -5
perkins17 I think mohs is a logarithmic scale of hardness which would indicate that diamond at 10 is significantly harder than corundum at 9. To me this is proven out by how easily diamond equipment grinds corundum. When I was grinding corundum on carborundum wheels, I remember trying to decide whether the wheels were doing the most grinding or whether the corundum was. Mohs is ordinal, so higher number just means "can scratch lower", but gives no quantifiable amount. Other scales like Knoop or Vickers are based upon measurements that can be quantifiably compared. There's a nice graph of Knoop vs. Mohs on the wiki page for the former.
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