sak
noticing nice landscape pebbles
Member since December 2013
Posts: 88
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Post by sak on Sept 14, 2014 21:59:10 GMT -5
Hi all,
Got a question for you guys regarding the recharging process with a rotary tumbler.
Assuming you know that none of your rocks are ready for the next stage, Is there any value In doing a complete clean out with new water & grit as opposed To just adding grit and letting the tumble continue?
Thanks for all your input.
Sak
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quartz
Cave Dweller
breakin' rocks in the hot sun
Member since February 2010
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Post by quartz on Sept 14, 2014 22:13:54 GMT -5
We tumble mostly real rough "hillside" mtl., pet wood, agate, and Jasper, in 5 gallon barrels. Two 10 day runs of 16 grit, then a 10 day of 80 with no cleanout, just adding grit. Then we clean out, sort, and run 220. After the 80 run, a majority of the mtl. is usually ready for 220. Considerable fiddling with the water has shown 2 3/4 qts. to be right, end up w/a good thick slurry at cleanout.
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Post by pghram on Sept 15, 2014 9:46:19 GMT -5
I agree, just don't let the slurry get too thick.
Rich
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nickinmass
off to a rocking start
Member since August 2010
Posts: 18
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Post by nickinmass on Sept 19, 2014 12:05:13 GMT -5
I usually pull out the stones and rinse/check for ones that are ready for the next step, but leave as much of the slurry as I can. Then I put the ones that aren't ready back in, add some new rocks to replace the ones that are moving on, and recharge. Leaving some of the slurry gives you a head start...
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jamesp
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Member since October 2012
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Post by jamesp on Sept 19, 2014 22:02:49 GMT -5
yes, preferably if slurry is thin. if thick, pouring out a portion and then adding water
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panamark
fully equipped rock polisher
Member since September 2012
Posts: 1,343
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Post by panamark on Sept 20, 2014 5:05:42 GMT -5
Interesting. My brief experiments have convinced me that a complete wash out results in faster rounding/polishing of the rough. I was thinking the slurry (which is very, very slippery by the time I change out) reduces the cutting action of the grit, but maybe it is time to run an experiment like James'.?? Some slurry is useful for carrying the grit throughout and coating the rocks, but how much is too much? What do Rob Jugglerguy, Chuck Drummond Island Rocks (why does it not bring up "Drummond Island Rocks" for you??), and Tom connrock say about this?
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Post by connrock on Sept 20, 2014 8:33:52 GMT -5
I've never experimented with using used slurry so I can't really say much. My thinking is that in the rough stage you want the grit to grind as much as possible and adding anything will only add a cushion that prevents the grit from doing it's job? Adding used slurry in the later stages may be a good thing but you would have to be careful so as not to add slurry with a more coarse grit then the stage you are in. I try to keep things simple and consistent so my recipes use powdered laundry soap and occasionally a little borax.
I think it would be interesting and informative to see an experiment with and without used slurry but everything would have to be done using the same exact type of tumbler,rough,grits,polish,etc,etc,etc or it's just a waste of time. connrock
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Post by Jugglerguy on Sept 20, 2014 8:51:39 GMT -5
I clean out thoroughly every week. I've never tried anything different, so I don't know. My rough stage takes longer than I think it should, so if there was room for improvement, it would be in the rough stage.
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blessed
spending too much on rocks
Member since January 2010
Posts: 329
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Post by blessed on Sept 20, 2014 13:34:15 GMT -5
I go about 10 days between cleaning out and changing grit. I also wash and scrub my barrels each time. Inside and outside. The newer the grit the faster the grind. James
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jamesp
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Member since October 2012
Posts: 36,154
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Post by jamesp on Sept 20, 2014 18:01:03 GMT -5
I always thought a slick medium slurry lubricates the grit. Consider a saw using water vs. a saw using oil. Slurry is not oil but it is slick. Nice to see a slurry, at least the rocks are being ground to cause one.
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tkvancil
fully equipped rock polisher
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Post by tkvancil on Sept 21, 2014 9:43:15 GMT -5
I just started two 6# barrels with nearly identical loads. One will get a recharge and one a cleanout. I'll post the results in about 3 weeks or so. This is something I've wanted to experiment with for a while and finally got around to.
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Post by Jugglerguy on Sept 21, 2014 9:48:50 GMT -5
Ken, I'm anxiously awaiting your results.
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panamark
fully equipped rock polisher
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Post by panamark on Sept 21, 2014 12:36:11 GMT -5
ditto. I am hoping you will do the "weigh them both" method to compare?
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tkvancil
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Post by tkvancil on Sept 21, 2014 12:53:02 GMT -5
I have started with 5 lbs. in each barrel. I weigh each load as a matter of practice, before and after. I plan to use the clean out barrel as a gauge. If it takes, say, one pound to get back to volume then the recharge barrel gets the same. This test is also meant to measure efficiency vs. economy. The recharge barrel gets 1 tbs. grit per pound, as per John Herchex's formula for a 3 pounder. The clean out barrel gets 2 tbs. per pound as per Lortone's suggested formula.
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jamesp
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Member since October 2012
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Post by jamesp on Sept 21, 2014 13:33:47 GMT -5
Far out. Am very curious about this.
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Post by Jugglerguy on Sept 21, 2014 14:34:55 GMT -5
If you change two variables, you're not going to be able to answer the original question. If I understand you right, one barrel is going to be completely washed and get two TBSP of grit each week. The other barrel is not going to be cleaned out, but is going to have one TBSP of grit added each week. If one barrel does better, you won't know if it was because of the amount of grit added or because of the old slurry left behind.
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eljay
off to a rocking start
Member since September 2014
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Post by eljay on Sept 21, 2014 18:44:09 GMT -5
Yes, exactly, you want to only have one difference between the barrels.
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sak
noticing nice landscape pebbles
Member since December 2013
Posts: 88
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Post by sak on Sept 22, 2014 2:37:28 GMT -5
Hi tkvancil -
Thanks for doing this experiment. I anxiously awaiting your results.
Thanks.
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tkvancil
fully equipped rock polisher
Member since September 2011
Posts: 1,546
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Post by tkvancil on Sept 22, 2014 9:49:36 GMT -5
If you change two variables, you're not going to be able to answer the original question. If I understand you right, one barrel is going to be completely washed and get two TBSP of grit each week. The other barrel is not going to be cleaned out, but is going to have one TBSP of grit added each week. If one barrel does better, you won't know if it was because of the amount of grit added or because of the old slurry left behind. You are very correct to point that out. I had the same thought after I already started. I think that using loss of mass as a gauge will give me a good idea of what is going on. The math can be used to show loss of mass per tablespoon of grit. Additionally I have decided to do a continued round of comparison with equal amounts of grit after the initial 3 weeks. Three weeks at a time because that is the interval I use for cleaning out a recharge barrel. I have plenty of stuff to use as fill and should be able to keep what is going in consistent between barrels.
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jamesp
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Post by jamesp on Sept 23, 2014 23:01:47 GMT -5
I have been tumbling coral over and over for a couple of years in the rotary. It became routine and predictable. Rio Grande agate too, also predictable. About the same recipe over and over. Always like to see the dirty slurry. checking every day till it started. Once dirty the grind seems to take off. Never let it get pasty. But learned to start w/water well below the rocks, or the grit seemed to wash off. If started w/the water level w/the rocks little grinding occurred and water stayed clear and no grinding was happening.I suppose the slurry should be sticky enough to pick up the grit and keep it stuck to the rocks.
Edit not sticky enough to stick to the rocks thick enough to keep the grit from settling
Dirty water with rock particles suspended is heavy and will float the grit better, more efficient for a rotary.
Vibs circulate grit more efficiently. Probably why they do not need much grit. Vibs just different. And do not need much water to serve as a carrier. Vib has every rock coated w/grit in 5 minutes if proper amount of water added. Suspension not an issue.
Coarse grind in the rotary tip: The coral is harder than about all the Rio Grande agate. But has a lot of soft limestone coating that quickly wears off and dirties the water unlike the Rio agate. It gives about a 2 day jump on the Rio Grande agate each coarse grit change. Adding crushed dry clay to the Rio agate at coarse grit change helped dirty the water immediately solving the problem. Fine grits about stay suspended even in clean water. They are easy. Coarser grits like 16 and 30 grit really need thicker slurry, much worse about settling and distributing well. Especially in a slower turning rotary. Non-abrasive additives like non petroleum based thickeners help suspend grit particles such as sugar. Spreading them more consistently throughout the slurry and lubricating the cutting action. Great for finishing steps. Rotaries all about grit suspension
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