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Post by captbob on Oct 10, 2019 15:40:45 GMT -5
I would expect to lose more after the coarse shaping run when in the 120/220 (or straight 120) step and maybe even a bit on 320 if I'm using that before 500. Just in my experience, not that I'm weighing rocks anymore after all these years, my 500 run is simply removing the finest of "scratches". Maybe enough material (rock) is being removed to register on some scale, (see who catches that) but as anal as I am, by the time my rocks make it to 500 many would be sending them to polish instead. After my weeks (or months) in 120/220, the grit has broken down finer than 500 anyway! All good. Bottom line is GOOD tumbles take time. - even if cheating with a vibe! Wouldn't doubt if maybe jamesp did some experimenting on such as well.
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Post by captbob on Oct 10, 2019 15:50:44 GMT -5
It’s easy to measure weight loss after a week in 500. When I said five percent, it wasn’t a guess. I haven’t bothered with 120/220 since ~2006. Waste of time. Well yes, if going straight to 500 after the coarse grind, I would expect to lose significant weight in the 500 run. 120/220 being a waste of time I have to completely disagree with. Unless the final coarse run lasted long enough... Any coarse grit will become a finer grit given time. All a bit of a learning curve. Someone that's Been There Done That may skip steps as they know what's going on and what longer run time results are.. I wouldn't recommend skipping 120/220 to anyone without years of experimenting behind them.
I'm pretty sure I could tumble a perfect load using ONLY 60/90 and polish - given time.
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Post by parfive on Oct 10, 2019 16:11:35 GMT -5
I'm pretty sure I could tumble a perfect load using ONLY 60/90 and polish - given time. Been there, done that and I wasn’t trying for perfect, just f’in around. And like I said to Mel, No long runs in 60/90. This was just stuff plucked out during re-charges every 5 -7 days.W/ no help from P-bucket . . . forum.rocktumblinghobby.com/thread/29736/experiment-60-90-ao-polish
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Post by Jugglerguy on Oct 10, 2019 20:12:48 GMT -5
Hopefully, you are running something between 60/90 and 500. By the time I get to 500 I wouldn't expect any weight reduction that a scale someone has at home could detect. Each step takes less time than the one before because there is less needed to be done. Polish being the possible exception, as I have found that the longer polish runs the better. Learned that when I let a polish cycle run for a year. Can't say for sure who it was, but I seem to recall Drummond Island Rocks or Jugglerguy did that experiment, and they were surprised at the amount of material that was lost after doing the coarse stage. I want to say it was 10% of mass through the final stages - clearly less and less was taken off as the material moved to polish. And, I'm with you on the time in polish. Whether it was psychological or not, I noticed a difference on my finished material from one week to two weeks and to where I finally settled in at three weeks. Wasn’t me, I’ve never weighed my rocks. I’m surprised no one has mentioned how silicon carbide and aluminum oxide break down. Silicon carbide breaks into smaller, but still sharp pieces. Aluminum oxide wears down into smaller, rounded pieces. Silicon carbide cuts better, while aluminum oxides smoothes things better. That’s why silicon carbide is better for early stages where you’re trying to grind away a lot of rock. Aluminum oxide is better for polishing. I use silicon carbide up through 220 grit at then switch to aluminum oxide at 500. I think jamesp taught me this. I have never tried silicon carbide at 500.
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Post by knave on Oct 10, 2019 21:22:35 GMT -5
The Polly Plastics grit kit has the 500 SC, when it’s gone we will have to try 500 AO...
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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 Oct 12, 2019 16:01:52 GMT -5
I mix the two - 50% 500 AO and 50% 500 SiC. Works for me When you Mia do you feel like you are getting faster results? Been away for a few days - just now getting back. No, not faster. I had a lot of both and I knew if I only used one or the other I'd have a lot of one unused. I just tried it as an experiment and I think it did a nicer job than strait SiC and at the same time a nicer pre-polish. Not saying its the best way, but I like it.
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JR8675309
freely admits to licking rocks
Member since August 2019
Posts: 751
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Post by JR8675309 on Oct 13, 2019 6:54:50 GMT -5
I decided to put the batch in AO prepolish after the SiC 500... I’ll let everyone know how it goes.
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Post by captbob on Oct 13, 2019 9:05:58 GMT -5
AO prepolish is AO500 I don't see any downside to going that route other than adding time to the tumble. Thinkin' it should help the final outcome for the rocks and be worth the time.
Allow the 500 SiC to run long enough to do its job!
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,154
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Post by jamesp on Oct 20, 2019 3:15:39 GMT -5
Can't say for sure who it was, but I seem to recall Drummond Island Rocks or Jugglerguy did that experiment, and they were surprised at the amount of material that was lost after doing the coarse stage. I want to say it was 10% of mass through the final stages - clearly less and less was taken off as the material moved to polish. And, I'm with you on the time in polish. Whether it was psychological or not, I noticed a difference on my finished material from one week to two weeks and to where I finally settled in at three weeks. Wasn’t me, I’ve never weighed my rocks. I’m surprised no one has mentioned how silicon carbide and aluminum oxide break down. Silicon carbide breaks into smaller, but still sharp pieces. Aluminum oxide wears down into smaller, rounded pieces. Silicon carbide cuts better, while aluminum oxides smoothes things better. That’s why silicon carbide is better for early stages where you’re trying to grind away a lot of rock. Aluminum oxide is better for polishing. I use silicon carbide up through 220 grit at then switch to aluminum oxide at 500. I think jamesp taught me this. I have never tried silicon carbide at 500. I found only one use for silicon carbide 500 Rob. Running obsidian and glass in the rotary for 7 to 10 days with SiC 500 if you have extra rotary barrels sitting vacant. This makes completion of the AO 500 (vibe) step much faster on difficult-to-polish softer materials like obsidian and glass. SiC and AO two completely different animals for the reasons you mentioned above. SiC cuts, AO smooths. Simple as that.
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