Kai
spending too much on rocks
Member since December 2018
Posts: 331
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Post by Kai on Jan 16, 2019 13:25:44 GMT -5
I'm sure this question has been asked somewhere already, but all the searching I did was unsuccessful, this forum is just TOO BIG! So I apologize if I'm repeating old topics... Anyway, I noticed that in the last two batches, my stones are flaking, like this: (sorry for the crappy photos, taken with my phone at bad light...)
Here you can see how big the piece is which flaked off the original stone: ...but they are all sizes, from this one above to tiny less-than-a-milimeter ones. If this was just one or two stones, I'd call it bad material and throw them away, but it's up to one third of the entire batch, very different stones. I didn't notice such damage in the rough, the flaking only started sometime in the middle of stage1 as far as I can tell. It's very disturbing now because grit gets caught in the cracks and I can't continue with the process. No matter how long I leave them (how much additional time I dedicate to the first step), there will still be some crevasses and flakes, looks like new ones are forming continuously. I thought maybe I wasn't filling up my drum enough and stones were crashing against one another too much, so I filled the drum up quite a lot for this last batch, maybe even a tiny little bit over the recommended quantity... but the result is still the same. Slurry is nice and thick, consistency of pancake batter or maybe just a little bit thinner. Help, what am I doing wrong?
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quartz
Cave Dweller
breakin' rocks in the hot sun
Member since February 2010
Posts: 3,341
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Post by quartz on Jan 16, 2019 23:27:38 GMT -5
This same situation is one I see frequently, especially with petrified wood. It's cracks already in the rocks before you started working on them that are now opening up. You aren't doing anything wrong. The cracks create one or more layers, the thin edges of the layers chip off during the tumbling process.
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Wooferhound
Cave Dweller
Lortone QT66 and 3A
Member since December 2016
Posts: 1,423
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Post by Wooferhound on Jan 18, 2019 23:13:49 GMT -5
Looks like Chert, it does that a lot.
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Kai
spending too much on rocks
Member since December 2018
Posts: 331
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Post by Kai on Jan 19, 2019 4:05:10 GMT -5
Looks like Chert, it does that a lot.
Indeed, some of my stones look like that a lot! (Not all of them, however...)
Thanks for the link.
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,158
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Post by jamesp on Jan 19, 2019 10:52:23 GMT -5
Felspar and fluorite does this too in a tumbler. Common occurrence for many rocks when tumbled with fractures.
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