jamesp
Cave Dweller
Member since October 2012
Posts: 36,548
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Post by jamesp on Nov 26, 2014 13:29:49 GMT -5
Yep. I agree. Some tumblers slower to get the sticky going on. Maybe some slick type rocks too. But less water will sure stick the grit to the rocks the first revolution. Sooner the better. And the thinner the slurry the more the abrasion. Have never really said to have the water so low because I did not want people to possibly damage some softer rocks. But my hard coral does not care, and a load with water 4 inches below the rocks is sure noisy in a PVC barrel, but the slurry is dirty the next day. The sound is that of destruction, but never noticed any damage. Obsidian may be another subject. I know that coral at a fast 60 RPM and water 4 inches below the rocks the grit is was used up quickly. And slurry really dirty. Seemed like they were rounding fast too, but still takes a long time.
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Post by Jugglerguy on Nov 26, 2014 14:36:44 GMT -5
I adjust the amount of water I add based on a couple factors.
For a six pound barrel:
If it's the first week of really rough material, I add 8 oz. of water. The sharp edges seem to grind off faster than more rounded rocks and makes a thicker slurry. After the first week I use less water, 6-7 oz.
I use more water if it's a softer material. I did the first stage for some Petoskey stones this summer just to round them and get the outer layer off. Since they're really soft, I sometimes doubled the water to 16 oz. and only ran them 3-4 days. The slurry was still very thick.
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tkvancil
fully equipped rock polisher
Member since September 2011
Posts: 1,546
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Post by tkvancil on Dec 14, 2014 16:00:17 GMT -5
Added another three week round to the experiment. This time using my normal amount of grit for a 6 pounder. Ten tablespoons. No difference in results as the clean out ground of more rock. From the recharge I removed 3/4 cup slurry and thinned the remainder with 1/2 cup water. This gave me a level of liquid below the top of the rocks. Had good tumbling sounds all the way through and the slurry never got overly thick. Each barrel started with 102 ounces of rock. 5.375 and 6 ounces added along the way for a total input of 103.375 ounces. Here is the breakdown ... Cleanout- 86.25 ounces at the end of the three weeks, Loss of 17.125 oz. mass or 16.5% (.57 oz. per tbs. grit) Recharge- 90.00 ounces at the end of the three weeks, Loss of 13.375 oz. mass or 12.9% (.45 oz. per tbs. grit) As I mentioned in my last update this is the final phase. My next step was to find the "break point" in regards to how much grit is enough. The 8 tbs. charge out ground the 6 tbs. charge. However this 10 tbs. charge did little to increase grinding. In fact the results in the cleanout were almost identical... 8 tbs. cleanout- 103.5 oz. in / 86.375 oz. out ; 17.125 oz. lost mass, 16.5% 10tbs. cleanout- 103.375 oz. in / 86.25 oz. out : 17.125 oz. lost mass, 16.5% This has been fun and interesting for me and hope some of you think it's been interesting as well. I'm going to stick with clean out but don't think that if you are a loyal and successful recharger you need to change. Here's the rocks. RC on the left, CO on the right.
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Post by Jugglerguy on Dec 14, 2014 16:43:36 GMT -5
Thanks again for the important experiment, Ken. I think we'll be referring back to this thread for years to come.
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,548
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Post by jamesp on Dec 14, 2014 17:27:25 GMT -5
Thanks for your efforts. Nice to know what is really going on. Glad the two were close.
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quartz
Cave Dweller
breakin' rocks in the hot sun
Member since February 2010
Posts: 3,352
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Post by quartz on Dec 14, 2014 23:14:56 GMT -5
Great experiment, well documented and easy to follow. Thanks for all the effort.
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Post by snowmom on Dec 15, 2014 7:17:34 GMT -5
Great thread, thank you!
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stonemaster499
noticing nice landscape pebbles
Member since July 2014
Posts: 97
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Post by stonemaster499 on Dec 21, 2014 11:30:56 GMT -5
thanks for the effort! Lot's of work, thought, and especially patience went into this. So many people have ideas, that make this quite difficult. The tumble manufacturers always tell you to use more, as they sell grit as well. I also like to see both methods turn out similar.
I use both techniques depending on the need. Time is saved on recharge method. Some weeks if you DON'T LOOK at your rotary tumble each week, this method cannot be beat..! Also, if tumbling softer stones, the recharge method offers necessary cushioning; as well as re-cycling old slurry to start/and or cushion. Grinding is slightly better in the cleanout, since you have pure rough grit, and none broken down along with some slurry to impede on the grinding action.
I modified an extra Model B pulley shaft to get the RPM from 18-22 (depending on my load) to 32-36 RPM. This has increased the grinding action, and my hard stones are ground n 1/2 the time. I will post how this is done. NOw i can switch speeds in 10 seconds.
thanks again!
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