jamesp
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Post by jamesp on Sept 30, 2016 3:57:52 GMT -5
Jim you mentioned the 30 grit being crushed by the big rocks.... 12 hours ain't long to break it down to nothing. I am no engineer but I am a decent hillbilly country boy can get by. So perhaps the effect is actually a hammer and anvil action. The grit is actually pulverized by the effect instead of sliding and grinding? Of course it's still getting great grinding and shaping very fast. Wonder if you could somehow moderate the action somehow to make the grit last longer and still be grinding with the effect of bigger scratches getting smaller and smaller for the last go round of 30 grit? My theory is the grit will cut a certain volume of stone. Do it slow or do it in 12 hours, cutting action is finite. SiC 30 will last less than 60 seconds if you put it between two slabs, add a little water, and rub them together with strong pressure. SiC 30 will last more than 60 minutes if you put it between two slabs and rub them together with light pressure. No hammer and anvil action, just constant pressure. The end result is about the same, except the gouge marks with higher pressure are probably deeper. Yesterday my big bloodstone got jammed in the barrel when I reached in the barrel to pull it out after 12 hours. I knew instantly something was wrong because I could feel the grit particles in the slurry. Big bloodstone got jammed and shut down the fast grinding action. Next time you fire up one of those 12 pound barrels with agates add a single 1.5-2 pound stone in there Bill. Just one. Wait till your slurry is built up say the first week, remove some 1-2 inch tumbles and replace volume with 1.5-2 pounder and hang on. You will be pouring off overly thick slurry and adding water and 30 grit every 12 hours. Fast slurry=Fast wear Scott's theory is bang on. Abrasives are good for 'X' amount of wear. Whether it is done quickly with high pressure or slowly with low pressure. If you fill your barrel with 1/8" stones 100% it will likely never break down the SiC 30. And the little stones will take forever to shape. Not enough pressure to make gouge marks= little/no cutting. All the cutting action is at the top of the rock pile. The rocks in the bottom of the barrel are hardly moving= no cutting action. A big rock sliding across the top section of the avalanche is bearing down way harder than 1.5 inch tumbles. Big rock is total game changer 30-55 times per minute, 24 hours a day. Sandpaper no different, it lasts longer with light pressure than hard pressure. To sand a piece of wood fast you bare down hard on the sand paper and rub fast. And that sand paper will give out much quicker, but you piece of wood has been shaped quicker. PS I just wanted to tumble some big rocks one at a time. This finding was by accident. I was not believing the grind rate, was puzzled. Then it hit me, tumbling grind rate is strictly a function of pressure and speed. As is grit life.
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jamesp
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Post by jamesp on Sept 30, 2016 5:11:29 GMT -5
Same thing happens in the vibe orrum. I have been polishing these big rocks with AO 80 in the vibe by themselves. And pea sized media. AO 80 is breaking down so fast that I get a pre-polish after 24 hours and darn nice polish after 48 hours on Mohs 7. Heavy rock has more psi. Probably more so in a vibe reversing directions at sonic speeds.
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jamesp
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Post by jamesp on Sept 30, 2016 6:01:38 GMT -5
I just weighed a typical 1.5 inch coral tumble.It weighs 26 grams. A 1.5 pound tumble weighs like 700 grams. 700 divided by 26 = ~ 27 times heavier. 27 times more rubbing/grinding force...that is why the rocks are grinding so fast. +/-, yes, but a heck of a lot more grinding force at 24/7. 26 gram tumble
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Post by orrum on Sept 30, 2016 7:41:42 GMT -5
Hey Jim that's a great idea putting s big tumble in my 12 pound barrel after a week!!! Wonder if I could do bookends in there? Rounded corners would be ok.
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jamesp
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Post by jamesp on Sept 30, 2016 7:57:15 GMT -5
Hey Jim that's a great idea putting s big tumble in my 12 pound barrel after a week!!! Wonder if I could do bookends in there? Rounded corners would be ok. Give it a go Bill. Would not go over 2 pounds(unchartered territory). Only one at a time. To avoid them beating each other. Big rock a bonus. Fast grind a bonus. win win
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Post by captbob on Sept 30, 2016 8:11:06 GMT -5
Would not go over 2 pounds(unchartered territory). Only one at a time. To avoid them beating each other. Why not? Uncharted territory doesn't seem to bother you. There a reason to not go as big as you can fit in the barrel?
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Post by orrum on Sept 30, 2016 8:21:08 GMT -5
I got a tumbler loaded with fire agate without fire yesterday, full of vugs etc and doesn't grind fast at all! Stuff is hard!!! Perfect opportunity to put a big boy in now???
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Post by captbob on Sept 30, 2016 8:32:36 GMT -5
I wouldn't with fire agate. Even with no fire, you are looking at some pretty cool shapes. Hate to ruin 'em.
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Post by 1dave on Sept 30, 2016 8:38:41 GMT -5
Impressive Tumbling Thread!
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jamesp
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Post by jamesp on Sept 30, 2016 8:47:00 GMT -5
Would not go over 2 pounds(unchartered territory). Only one at a time. To avoid them beating each other. Why not? Uncharted territory doesn't seem to bother you. There a reason to not go as big as you can fit in the barrel? In time. Baby steps I guess. Getting ready to pre-grid that white rock with the black plumes from roy deemed too good to tumble. If a rock is deemed to good to tumble it will be the first to hit the tumbler. This is a tumbling forum. I reserve my right to tumble thusly.
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jamesp
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Post by jamesp on Sept 30, 2016 8:51:54 GMT -5
I got a tumbler loaded with fire agate without fire yesterday, full of vugs etc and doesn't grind fast at all! Stuff is hard!!! Perfect opportunity to put a big boy in now??? May want to stick with hard agates Bill. I put test slabs 3/16 inch thick in with the 2 pounder and had some crack. 3/16" slabs not equal to typical round tumbles in break strength. moss, fortification, Montana, snakeskin, bloodstone, Brazil, coral, most jaspers, chert, etc All those dead hard tough agates.
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jamesp
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Post by jamesp on Sept 30, 2016 8:53:31 GMT -5
Impressive Tumbling Thread! I think the added big rock just opened pandora on faster grind times Dave. Actually very sure of it. By accident.
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Post by 1dave on Sept 30, 2016 9:54:19 GMT -5
Original Admin , krazydiamond , stoner , With his vast experiments, We need to talk jamesp into writing a new sticky thread about the ins and outs of tumbling! What to call it? "Tumbling Techniques" or "The ABC-XYZ of Tumbling" or ?? But only he can wrap it up from beginning to end!
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Post by captbob on Sept 30, 2016 9:57:17 GMT -5
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Deleted
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Post by Deleted on Sept 30, 2016 10:05:56 GMT -5
Why not? Uncharted territory doesn't seem to bother you. There a reason to not go as big as you can fit in the barrel? In time. Baby steps I guess. Getting ready to pre-grid that white rock with the black plumes from roy deemed too good to tumble. If a rock is deemed to good to tumble it will be the first to hit the tumbler. This is a tumbling forum. I reserve my right to tumble thusly. Probably depends on shape too. My gut is saying ~1/2 barrel diameter is ideal for fast grind. This can be round, ovalish or long like a sweet potato. Longer equals heavier. Jim what would you say is ratio of the starter bloodstone to barrel diameter?
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Post by captbob on Sept 30, 2016 10:28:50 GMT -5
Jim what would you say is ratio of the starter bloodstone to barrel diameter? He has his home made barrels constraining what will fit in the end cap opening. Folks with a "regular" barrel can go larger. The 5 1/2 lb Rio I'm thinking of trying would be way past half the barrel diameter in one of my 15 lb barrels. I doubt it would truly tumble in the barrel. It would move around some and the smaller filler would have to be what grinds on it. May start that this weekend just to see if it's doable. Gotta add grit to my 2 3/4 lb Rio tumble today and check on what 3 days has done. Well, I gotta check the grit anyway, will see if it's time to add more.
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Deleted
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Post by Deleted on Sept 30, 2016 10:48:02 GMT -5
Jim what would you say is ratio of the starter bloodstone to barrel diameter? He has his home made barrels constraining what will fit in the end cap opening. Folks with a "regular" barrel can go larger. The 5 1/2 lb Rio I'm thinking of trying would be way past half the barrel diameter in one of my 15 lb barrels. I doubt it would truly tumble in the barrel. It would move around some and the smaller filler would have to be what grinds on it. May start that this weekend just to see if it's doable. Gotta add grit to my 2 3/4 lb Rio tumble today and check on what 3 days has done. Well, I gotta check the grit anyway, will see if it's time to add more. Awesome! Hope to see the results. I have to get my tumbler built. Crud. Time is a curse word lately.
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jamesp
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Post by jamesp on Sept 30, 2016 11:45:32 GMT -5
Original Admin , krazydiamond , stoner , With his vast experiments, We need to talk jamesp into writing a new sticky thread about the ins and outs of tumbling! What to call it? "Tumbling Techniques" or "The ABC-XYZ of Tumbling" or ?? But only he can wrap it up from beginning to end! This one still in early stages. Hopefully it is simple as adding a 1.5 pound rock to your Mohs 7 tumbles.
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jamesp
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Member since October 2012
Posts: 36,555
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Post by jamesp on Sept 30, 2016 11:57:32 GMT -5
In time. Baby steps I guess. Getting ready to pre-grid that white rock with the black plumes from roy deemed too good to tumble. If a rock is deemed to good to tumble it will be the first to hit the tumbler. This is a tumbling forum. I reserve my right to tumble thusly. Probably depends on shape too. My gut is saying ~1/2 barrel diameter is ideal for fast grind. This can be round, ovalish or long like a sweet potato. Longer equals heavier. Jim what would you say is ratio of the starter bloodstone to barrel diameter? No doubt there was a jam yesterday. I know I added more rocks to just over 3/4. It was too many. I say 5/8 full is best. That barrel has a 5 inch inside diameter and longer. The bloodstone is 5 X 4 X 2 aprox. Just put in new barrel at 6 inches ID. Removed the tumbles and replaced and pulled any bigger than 1.75. I could tell by the sound and the grit in the slurry that it jammed yesterday. If running smaller rocks then it is almost impossible for a jam with a big rock. I was running the bloodstone in an old 6 inch ID barrel that was worn out and it leaked so went to the 5 inch barrel 2 days ago. Yes, size ratio is important. Both barrel to big rock and big rock to media, and combination of all of them.
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jamesp
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Post by jamesp on Sept 30, 2016 12:02:12 GMT -5
Jim what would you say is ratio of the starter bloodstone to barrel diameter? He has his home made barrels constraining what will fit in the end cap opening. Folks with a "regular" barrel can go larger. The 5 1/2 lb Rio I'm thinking of trying would be way past half the barrel diameter in one of my 15 lb barrels. I doubt it would truly tumble in the barrel. It would move around some and the smaller filler would have to be what grinds on it. May start that this weekend just to see if it's doable. Gotta add grit to my 2 3/4 lb Rio tumble today and check on what 3 days has done. Well, I gotta check the grit anyway, will see if it's time to add more. Those barrels that are 8 inches will be able to handle one larger rock better than a 6 inch barrel. Oh yea, do have an 8 inch PVC barrel but still limited by the 4 inch opening. Could do a 6 inch bushing for an 8 inch PVC.
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