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Post by grumpybill on Aug 17, 2017 20:08:31 GMT -5
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jamesp
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Post by jamesp on Aug 17, 2017 20:26:34 GMT -5
Yep, if you do not add slurry thickener the heavy 20-30 grit may well stick to the ends and not break down. The graph works for water. Tumbler companies like that don't mention slurry thickener.(I haven't read their info but guessing they made no mention of slurry thickener). At 30 RPM and a good starting slurry my 30 grit is broke to nothing easily in 2 days. Sorry, I disagree with them. Strongly. 'More particle' theory - not. 30 grit breaks to 35 then 40 then 45 then 50 then 55 then 60 or similar. Don't buy that either. The mere fact they are showing a photo of 20 grit SiC particles after two weeks tells the story. They ain't using slurry thickener to suspend the heavy 20 and 30 grit. Photo has no mud. No slurry. Looks like clean water. That's a dead giveaway. Two weeks rolling and no mud ? Bad day. "Large 20 mesh grit particles remaining after two weeks of tumbling. At this point in the tumbling most 60/90 grit had been reduced so much in particle size that it was much less effective. If the tumbling time was increased to four weeks, the grit shown here would still be removing material. So, this size of grit might be more effective than 60/90 in unattended tumbling of one month in duration of more." Yep, read their article an no mention of slurry thickener. 60 grit is easily circulated(suspended) by clean water. 30 grit is easily circulated(suspended) by slurry thickened water. NOT by clean water. 30 grit is gonna cut faster than 60 grit. Try 30 grit sandpaper verses 60 grit.
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Post by grumpybill on Aug 17, 2017 20:36:17 GMT -5
Also note that they qualify their results as possibly only applying to small tumblers.
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jamesp
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Post by jamesp on Aug 17, 2017 20:41:20 GMT -5
Also note that they qualify their results as possibly only applying to small tumblers. And that is a fact Bill. 60 grit may well be great choice for small barrels. Mine are 6 inches on the I.D. and tear 8-16-30 grit SiC with no effort. Never used a 1.5 or 3 pound barrel, can't speak for them.
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jamesp
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Post by jamesp on Aug 17, 2017 20:47:26 GMT -5
Slurry thickener would cramp their style. Take a bit of practice to get the thickness dialed in. Doubt they want to deal with the bombardment of questions. They have good basic marketing approach. Do it the easy reliable way. without hot rodding.
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Post by grumpybill on Aug 17, 2017 21:00:18 GMT -5
On a side note: The polished stones they sell are done in a 6000lb tumbler.
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notjustone
spending too much on rocks
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Post by notjustone on Aug 17, 2017 22:34:12 GMT -5
lets not forget they used large ceramics which don't really weigh enough to crack or breakdown the 20 grit. ive noticed that really big sic takes a lot to break the chunks up. if they had used 3lbs ceramics and a 1 pound grinder rock I guarantee the results would have been different. in my opinion soft barrels make a huge difference my pvc barrels definetly break down 30 grit a lot faster than my ar-12 does even with the high speed brass motor. noticeable enough that I don't even use my ar-12 anymore. here that jamesp the finer grits even do a lot of cutting and to think we were going to screen them out.
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notjustone
spending too much on rocks
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Post by notjustone on Aug 17, 2017 22:42:24 GMT -5
but I do agree with them on small barrels I tried 30 grit in my 3lbs barrel with some special rocks I had ran separate some marfas I got from Jeremy and some self collected garnets and my 30 grit wasn't broke down after a month. so I ended up throwing them in the 8 inch pvc barrels with my other rocks. if all I had was the 3lbs barrels I would have switched to the 60-90 because the 30 wasn't breaking down.
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quartz
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Post by quartz on Aug 17, 2017 23:01:29 GMT -5
This looks to me like a quickly drawn conclusion caused by someone telling a subordinate to do an experiment so the writeup will fill a page somewhere. I see my 16 grit disappear in two weeks, using a larger PVC barrel and much heavier fodder.
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Post by captbob on Aug 17, 2017 23:20:27 GMT -5
lets not forget they used large ceramics which don't really weigh enough to crack or breakdown the 20 grit. ive noticed that really big sic takes a lot to break the chunks up. if they had used 3lbs ceramics and a 1 pound grinder rock I guarantee the results would have been different. in my opinion soft barrels make a huge difference my pvc barrels definetly break down 30 grit a lot faster than my ar-12 does even with the high speed brass motor. noticeable enough that I don't even use my ar-12 anymore. Bingo, thinking that super coarse would breakdown with just ceramics in the barrel was a foolish waste of time. Notjust... don't mothball that AR-12. That is my favorite barrel for polishing and for really soft rocks. I'd suggest that you keep it in the rotation just for those purposes - especially polish stage. Not so sure I'd use a high speed motor on the polish stage though, but I haven't tried that. Not the best barrel for a coarse grit run.
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notjustone
spending too much on rocks
Member since January 2017
Posts: 426
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Post by notjustone on Aug 17, 2017 23:56:28 GMT -5
lets not forget they used large ceramics which don't really weigh enough to crack or breakdown the 20 grit. ive noticed that really big sic takes a lot to break the chunks up. if they had used 3lbs ceramics and a 1 pound grinder rock I guarantee the results would have been different. in my opinion soft barrels make a huge difference my pvc barrels definetly break down 30 grit a lot faster than my ar-12 does even with the high speed brass motor. noticeable enough that I don't even use my ar-12 anymore. Bingo, thinking that super coarse would breakdown with just ceramics in the barrel was a foolish waste of time. Notjust... don't mothball that AR-12. That is my favorite barrel for polishing and for really soft rocks. I'd suggest that you keep it in the rotation just for those purposes - especially polish stage. Not so sure I'd use a high speed motor on the polish stage though, but I haven't tried that. Not the best barrel for a coarse grit run. the ar-12 was a freebie someone gave my wife one day. the higher speed motor for brass tumbling. I used it when I first got it to polish a big chunk of lapis that wouldn't fit in the vibe. it polished but nothing to write home about too fast. tried it as course barrel with 30 grit didn't like it as much as the 8 inch pvc barrels so it sits on a shelf now lol.
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Post by coloradocliff on Aug 18, 2017 3:11:34 GMT -5
On a side note: The polished stones they sell are done in a 6000lb tumbler. Bill, If you aren't adding a slurry thickener you might do it. Clay kitty litter from Walmart is cheap and works great to keep the grit suspended but MOST importantly it will stop your stones from getting bruised and having a lot of chips and cracks that wont show up for you until the later fine stages. The thickness should be like a malt and thicker than a milk shake. This slurry is too thick add a bit of water and close and go back to tumbling. Like jamesp said , you need to experiment some to get your amount of slurry dialed in. In a 15 pound barrel I use about 12 oz of kitty litter in between grit changes added to your rocks, fresh grit and water. Open it after an hour and see how thick, add more kitty litter if too thin and roll some more. Don't forget to take notes the fisrt few runs of rock you make.
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jamesp
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Post by jamesp on Aug 18, 2017 4:14:06 GMT -5
lets not forget they used large ceramics which don't really weigh enough to crack or breakdown the 20 grit. ive noticed that really big sic takes a lot to break the chunks up. if they had used 3lbs ceramics and a 1 pound grinder rock I guarantee the results would have been different. in my opinion soft barrels make a huge difference my pvc barrels definetly break down 30 grit a lot faster than my ar-12 does even with the high speed brass motor. noticeable enough that I don't even use my ar-12 anymore. here that jamesp the finer grits even do a lot of cutting and to think we were going to screen them out. Quite a few folks have complained about SiC 30 not breaking down in 3 pound barrels. No doubt bigger barrels have heavier grinds. As does bigger rocks or a big grinder rock added. Keep in mind 6 sided and 8 sided hex/octagon barrels create a gentler tumble if I am not mistaken, round barrels the most aggressive. I may be wrong, but I think that is the way it goes. They are not apples for apples. Pretty sure it is the round barrels that keep the rocks in a harder roll. I wish that Covington engineering would comment on their clay thickener. Covington sells SiC 14. that size would require a large tumbler and/or adding thickener to suspend it. I have been screening the bulk grit John and putting it in the SiC 30 barrel. I will run the big bulk particles for the time release hard coarse grind. On the last coarse grit run I use the 30 SiC/fine bulk SiC mix and let it run till very broken down in prep for the vibe. Sort of a 2 stage coarse.
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jamesp
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Post by jamesp on Aug 18, 2017 4:41:43 GMT -5
"Open it after an hour and see how thick, add more kitty litter if too thin and roll some more." Good point coloradocliff. I may come back the next day and check it, whatever is convenient. I come back and check/adjust slurry thickness. If good, then walk away for a week. The bulk grit is working well for me at one week runs at a fast 55 RPM. 55 RPM, 6" PVC, 1 CUP clay, double dose of 1 CUP bulk abrasive, 75-80% rock fill, at least one grinder rock 1 to 1.5 pounds. Getting some nasty grind rates and only servicing weekly. Active grit still present days 3-4-5. Often several large chunks of the bulk SiC left. 55 RPM with a grinder rock is allowable with the thickener and 75-80% rock fill. Seems I have about a full week fast/efficient grinding and only doing clean outs on the weekend. The last coarse grit run is done for about 10 days using SiC 30 and the finer screened bulk SiC and a few added rocks to bring rock level up to 80-85% for gentler run. Moving to 80-85% rock fill stifles the tumble a lot. This run is prep run for vibe.
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Post by grumpybill on Aug 18, 2017 5:33:53 GMT -5
I'm glad this thread generated so much informative discussion!
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Post by grumpybill on Aug 18, 2017 5:51:23 GMT -5
Keep in mind 6 sided and 8 sided hex/octagon barrels create a gentler tumble if I am not mistaken, round barrels the most aggressive. I may be wrong, but I think that is the way it goes. A Lortone 3lb barrel has small ripples on the inside...sort of a cross between smooth and hex/octagon. The Lortone 1.5lb barrels are smooth inside. My (admittedly limited) experience is that the little (completely smooth) critters need twice as many runs to remove saw marks as the (rippled) 3lb. barrel. The barrels are the same diameter, so the weight of the stones, as they're tumbling down, should be the same.
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jamesp
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Post by jamesp on Aug 18, 2017 6:20:58 GMT -5
Keep in mind 6 sided and 8 sided hex/octagon barrels create a gentler tumble if I am not mistaken, round barrels the most aggressive. I may be wrong, but I think that is the way it goes. A Lortone 3lb barrel has small ripples on the inside...sort of a cross between smooth and hex/octagon. The Lortone 1.5lb barrels are smooth inside. My (admittedly limited) experience is that the little (completely smooth) critters need twice as many runs to remove saw marks as the (rippled) 3lb. barrel. The barrels are the same diameter, so the weight of the stones, as they're tumbling down, should be the same. I am sure glad you found this article Bill. I have kept an eye on that company over the years. Paying attention to them. Oh boy. Yep, I have had a 12 pound 12 sided Lortone. Darn near round. Fine barrel, nice thick solid rubber. OK, barrels and size and shape and speed play a big roll. Assuming both 1.5 and 3 are at same speed ? Think about this one, a 4 inch diameter barrel 3 inches wide and a 4 inch diameter barrel 12 inches wide(just to exaggerate the widths). What effects are the walls being close together going to have on the rocks rolling/tumbling ? They will as the walls get closer together, got to. Especially if barrel is only 3 inches wide and you are rolling 2 inch rocks. Darn thing will likely jam. Or constipate the movement. I have asked myself same question about one 12 pound Lortone rotary barrel verses two - 6 pound Lortone's...both equal in diameter. This came up a year ago when I redid my 6 inch PVC barrels from being 24 inches long to 6 inches long. Had some 6 inch diameter PVC barrels that were 3+ feet long in early years. It was a hassle to shake the rocks out the rocks thru the 4 inch opening for clean outs. Heavy too. I do a lot of experimenting and love running a big rock one per barrel, so the increased number of barrels by making them narrower. I don't see much difference in coarse grind with 6" barrel length = 6" barrel diameter.
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jamesp
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Post by jamesp on Aug 18, 2017 6:42:51 GMT -5
On a side note: The polished stones they sell are done in a 6000lb tumbler. There was a fellow on here from Madagascar that owned commercial tumblers. He imported like 300 pound tumblers from China. They gave fast production. Heavy hard grinding loads. He also imported similar giant vibes. may be that their heavy loads finished rock quicker. Same argument, shallower vibe bowl verses deep vertical bowl(like Lotto). Tall hopper is going to have more head pressure. Shape has impact on performance.
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Post by grumpybill on Aug 18, 2017 6:45:45 GMT -5
jamespThey both turn at approx. the same speed depending on how heavily I load the 3 x 1.5lb machine. It probably needs a new belt, but I haven't gotten around to changing it.
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jamesp
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Post by jamesp on Aug 18, 2017 7:02:45 GMT -5
jamespThey both turn at approx. the same speed depending on how heavily I load the 3 x 1.5lb machine. It probably needs a new belt, but I haven't gotten around to changing it. Figured they were rolling the same. Watching the disappearing of the saw marks is a great test to see how fast you machine is grinding. My diamond grinder leaves similar marks. They can be seen disappearing. If I am grinding the surface of a piece of steel down I will turn the grinder on edge and grind a depth slot on the surface. Then keep grinding with the flat side of the grinder till the slot disappears from the surface. Slot depth serves as a depth reference. Saw marks are same game. It is hard to 'quantify' coarse grind rate. Uh, shape-rounder-getting smaller. Removing a ground slot into the rock of known depth will give information. Some rocks are stubborn to grind, invariably the grind marks are slow to tumble away. Telling that you have a tough/hard rock material. Easy to see if rolling 6 pounds of ground rock. At first clean out you will quickly see which ones lost their grind marks first.
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