Benathema
has rocks in the head
God chased me down and made sure I knew He was real June 20, 2022. I've been on a Divine Mission.
Member since November 2019
Posts: 703
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Post by Benathema on Oct 5, 2020 12:12:37 GMT -5
I did. Not the greatest apples to apples comparisons since each rock is different and changes as you go. Then a couple instances where I ran out of grit and changed to a different size partway through... So... Not the greatest systematic approach, but it's something.
The big rocks were done in 12 lb barrels with 12 tbsp grit for each stage and water laser eyeballed. Mass removal per week appeared greater for the 36 SiC than 46/70 than 60/90.
The plots I made in those threads are labeled with what grit was used for however many weeks.
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Post by joshuamcduffie on Oct 5, 2020 13:40:08 GMT -5
I know silicon carbide is a 9.5 on the mosh scale, and aluminum oxide is a 9, my question is would the a.o. Make a good medium stage, I’ve got some 400 grit s.c. ordered for pre polish The SiC tends to fracture and the grit retains a jagged shape, so even after the particles begin to break apart they still retain a lot of cutting and scratching ability. The aluminum oxide surface begins to get more rounded or polished as it wears. That's why people use SiC as a grit and AO as a polishing compound. Some folks ( jamesp) here use 200 AO in a vibratory tumbler and just let it wear down to a polish, I think.
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,159
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Post by jamesp on Oct 5, 2020 15:32:35 GMT -5
To shape rocks silicon carbide is best. Final surface work 500-1000-polish is best done with aluminum oxide in most cases. I have had good luck with aluminum oxide 220 and 80 for that matter after the silicon carbide step(step 2). Most use silicon carbide 220 for step 2 though. Yes, AO 220 can take you to a medium polish unlike SiC 220 but it takes a while.
Don't waste your time shaping rocks with AO though. It makes a good pre polish and polish.
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Tone
off to a rocking start
Member since September 2020
Posts: 4
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Post by Tone on Oct 14, 2020 13:37:14 GMT -5
Thanks guys for the info
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