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Post by pauls on Oct 17, 2014 16:24:09 GMT -5
This is a great experiment. Someone is doing the science, fantastic. For what its worth, talking scientifically here and playing devils advocate, so don't hang me. Is the talk of the grit breaking down actually relevant? I know it indicates that things are happening, but its not actually achieving much as far as our process goes. The process would work better if the grit stayed at 80 grit rather than being smashed down to finer size. Yes I know about fresh sharp edges being exposed as it breaks down, so another variable.
The state of the slurry is a good indicator that things are happening and it keeps the grit in suspension, but its not actually necessary and possibly cushions the action of the grit between stones. This is an area I played around with a while back but as far as I was concerned the results were possibly slightly better but not worth the extra trouble and the danger involved. I discovered quite by accident that really concentrated Caustic Soda solution dissolves glass, (don't ask my wife about her Pyrex jug) I reasoned that glass being silica, it should work with rocks too so put a big cup full into my tumbler barrel, I do not know if it actually made the process quicker as I didn't have a control barrel, but I do know it changed the nature of the slurry completely, all the ground up rock dissolved into solution as Sodium Silicate. When I opened the barrel all I had as a slurry was an almost black slurry of smashed up grit. Yes grinding was happening and it seemed to be working well. Was it any quicker? Maybe. Was it any better? Possibly. Was it more trouble? It certainly was, getting kitted up in full safety gear just to open a tumbler barrel was pretty weird. Disposal of a concentrated Sodium Silicate solution presents a few challenges in itself for most people. I have a use for it in my backyard foundry. Actually being Sodium Silicate solution it might be useful to help heal cracks in rocks and fix porous stones as described elsewhere on this board, but I haven't taken it there yet.
Anyway, I will be watching this thread with interest and I am glad someone is having a go at quantifying things that we all suspect but have trouble actually pinning down due to so many variables.
Paul
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tkvancil
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Post by tkvancil on Oct 18, 2014 17:17:19 GMT -5
I have given some thought to breakdown pauls. It does show that something is happening for sure. Poor conditions in the tumbler means no breakdown. However it may be part of the reason some folks swear by recharge. For instance, take my 3# tumblers which I have been using recharge in now for several months. I start each cycle with 2 tbs. grit and add 2 more each week, three weeks at a time. Assume a 50% breakdown every week. Week two I'd have 2 tbs. 160 and 2 tbs. 80. During week three I'd have 2 tbs. 320, 2 tbs. 160 and 2 tbs. 80. I know finer grits don't remove a lot of material but they do remove some. Part of the reason for this experiment is to see if I've been doing myself any good in the 3 pounders. I'm not sure it's been any faster, 3 pounders aren't particularly aggressive to begin with. The surface on the rocks I deem ready for stage two do seem to have a very nice smooth finish. casual observation only. Surface area would be another unknown. I tried to split these batches equally in number,size and weight. We all know a batch without a good quantity of smalls doesn't grind well. In part this is because surface to surface contact is reduced in a batch that has nearly all larger rocks. The caustic soda as an additive is interesting. I wouldn't like suiting up in safety gear for a cleanout either. It's enough of a pain for me to wear a dust mask when measuring grit. I don't really expect this experiment to be definitive but should be enlightening. At least to me.
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tkvancil
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Post by tkvancil on Nov 2, 2014 11:41:15 GMT -5
Weeks 4 to 6, phase 2 of the experiment, is now complete. In this part of the experiment each barrel got 6 tbs. 80 grit per week. My normal charge for a 6# barrel is 10 tbs. coarse grit. I have often heard that one needs only 1 tbs. grit per pound of rock. So in part I'm trying to find out if I've been wasting grit by using less than I usually do. After the first 3 weeks I had shuffled the batches but neglected to take pics of them. Took a long time to sort the loads evenly and there was other things I needed to get to. Each batch weighed 5 lb. 12 oz. at the beginning of week 4. Both got 6 tbs. 80 grit and 1/2 cup water. At the end of week 4 I had 5 lb. 7 1/2 oz. of rock left in the clean out barrel. Four and a half ounces of mass lost. The cardboard jig was used to ensure barrel was not overloaded. Six ounces of filler gave me a generous 2/3rds. Both barrels got 6 oz. filler and 6tbs. grit. End of week 5 the clean out barrel lost 5 oz. mass and took 8 ounces filler to give 2/3rds. Both barrels got the 8 oz. filler and 6 tbs. grit. I toyed with the thought of thinning the recharge barrels slurry here. It was pretty thick. Did not do so and by Wednesday (charged Saturday) it was clunking. I chose to let it go. Here are the batches at end of week 6 rinsed and dry. The cleanout barrel (right) was again down 5 ounces. I did take some rocks out of each load that were ready for the next stage. 27 pieces weighing 5 1/4 oz. from the cleanout and 25 pieces from the recharge weighing 3 1/8 ounces. Can't read too much into this because there was one Bahia nodule from the recharge I was on the fence about. Returned it to coarse but if had kept it both would have been nearly equal in regards to having rocks ready for next step. My results were quite different from the first phase and I may have to eat my words. 106 ounces of rough went into each barrel over the 3 weeks. 91.5 oz. out of the cleanout. Total mass lost 14.5 oz. or .81 oz. per tbs. grit. 95.25 oz. out of the recharge. Total mass lost 10.75 oz. or .60 oz. per tbs. grit. I went back through my notes and found that using 10 tbs. grit I was grinding off 8 to 12 ounces depending on the type of material. With 4 to 5 lost using 6 tbs. it would seem more grit is faster. The next three weeks I'm using 8 tbs. per barrel which should give some insight. Again comments, questions, criticism and suggestions welcome.
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jamesp
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Post by jamesp on Nov 3, 2014 3:38:15 GMT -5
Ken, I have been pondering a way to run this coarse grind test in a simple way. It is complicated by getting equal batches of rocks and adding equal batches of rocks. You have done a stellar job on that task. 1) I was thinking that grit should be added equally to each barrel every 7 days regardless of all other conditions so grit consumption is the same. 2) Rock additions should be made every 7 days to have equal volume of rocks at the start of every 7 days, weight of additions recorded. 3) The barrel that gets a clean out is simple, it gets cleaned out and new grit added every 7 days, rocks added as needed. 4) The barrel that does not get cleaned out is treated the same as far as grit and rock additions. However:
Slurry should be maintained at a healthy thickness the entire 7 days in the barrel that does not get a complete clean out **( requiring adjustments)
Since labor is used cleaning the clean out barrel then labor can be spent maintaining a healthy slurry in the other barrel by simply adding a bit of water and pouring off some slurry to maintain a nice slurry that is not overly thick.
The problem in the clean out barrel is if it has unused grit at the end of each 7 days ?? i.e., is grit being thrown away in the clean out barrel ? If there is unused grit after 7 days then something is wrong IMHO. And this issue should be addressed. It seems that rock wear is directly related to grit breakdown which is directly related to slurry production. No wearing, no thickening slurry.
The other problem is if the dirty barrel has grit that is left over at the end of the entire test, by the same token.
I am biased, I put lime or dried slurry in the barrel to get a thicker than water slurry within 24 hours at start-up. And do a total clean out after 3-4 weeks(3-4 grit additions). But never let the slurry get too thick at any point by pouring off some slurry and adding water as needed. That's just my way for what it is worth. The obsidian ground fast and made fast slurry. Had to clean it out after 2 grit changes, but the grit ran 10-12 days before breaking down instead of 5-7 days for agate.
Great test. Tricky, as there is a lot of variables. You always have great tumbles. Got my attention.
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tkvancil
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Post by tkvancil on Nov 3, 2014 10:27:48 GMT -5
Ken, I have been pondering a way to run this coarse grind test in a simple way. It is complicated by getting equal batches of rocks and adding equal batches of rocks. You have done a stellar job on that task. 1) I was thinking that grit should be added equally to each barrel every 7 days regardless of all other conditions so grit consumption is the same. 2) Rock additions should be made every 7 days to have equal volume of rocks at the start of every 7 days, weight of additions recorded. 3) The barrel that gets a clean out is simple, it gets cleaned out and new grit added every 7 days, rocks added as needed. 4) The barrel that does not get cleaned out is treated the same as far as grit and rock additions. However: Slurry should be maintained at a healthy thickness the entire 7 days in the barrel that does not get a complete clean out **( requiring adjustments) Since labor is used cleaning the clean out barrel then labor can be spent maintaining a healthy slurry in the other barrel by simply adding a bit of water and pouring off some slurry to maintain a nice slurry that is not overly thick. The problem in the clean out barrel is if it has unused grit at the end of each 7 days ?? i.e., is grit being thrown away in the clean out barrel ? If there is unused grit after 7 days then something is wrong IMHO. And this issue should be addressed. It seems that rock wear is directly related to grit breakdown which is directly related to slurry production. No wearing, no thickening slurry. The other problem is if the dirty barrel has grit that is left over at the end of the entire test, by the same token. I am biased, I put lime or dried slurry in the barrel to get a thicker than water slurry within 24 hours at start-up. And do a total clean out after 3-4 weeks(3-4 grit additions). But never let the slurry get too thick at any point by pouring off some slurry and adding water as needed. That's just my way for what it is worth. The obsidian ground fast and made fast slurry. Had to clean it out after 2 grit changes, but the grit ran 10-12 days before breaking down instead of 5-7 days for agate. Great test. Tricky, as there is a lot of variables. You always have great tumbles. Got my attention. James, on points 1 through 4 you are spot on. This is exactly what I have been doing. In this particular case there was no coarse grit left at the end of weeks 4 to 6 in the cleanout barrel. The grit was all broken down in the recharge barrel at the end as well. I do think that the slurry was overly thick in the recharge and plan on doing the labor you mentioned in the third phase. It is entirely likely that the too thick slurry cushioned the rocks. I know that a lot of folks add some dried slurry to their tumbles to get things "jump started". I will probably play with this method at some point as well. After this 3 week phase with 8 tbs. grit I'm pretty sure I'll continue on with my normal 10 tbs. charge. The only thing I'm convinced of so far is that 1 tbs. per pound of rock is not enough at least in larger barrels.
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jamesp
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Post by jamesp on Nov 3, 2014 11:43:47 GMT -5
Ok, It is what it seemed. You have a lot of things going on with measurements. And an intimate relationship with the scales . Watching w/interest. It is a big task.
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sak
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Post by sak on Nov 5, 2014 3:39:23 GMT -5
Hi Ken - Thanks for following up with this experiment. I've been anxiously waiting for your results. It will be interesting to see what your final thoughts will be on this experiment. I have a question for you...if it's determined that re-charging to more effective/economical, etc.. and that's all you do, how would you be checking the rocks then to determine what is ready for the next stage? Sak...
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tkvancil
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Post by tkvancil on Nov 5, 2014 9:39:06 GMT -5
sak I have been using recharge in my 3# tumblers. With those I go for three weeks at a time. Start week one fresh then add grit week two and week three. At the end of third week rinse , sort and start fresh again. I'd probably stick to that schedule. jamesp mentioned above that he cleans out every three to four weeks after recharging along the way. His and my experience lead me to think that 3 to 4 week intervals to check rocks and start over again is a good way to go.
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Post by Jugglerguy on Nov 5, 2014 14:11:03 GMT -5
I'm really hoping that the clean out method is better. Obviously, I want to use whatever method gets the rough grind done the quickest, but if it's close, I"m going to stick with the clean out method rather than the recharge for a couple reasons.
I think we all tumble rocks because we enjoy playing with and looking at rocks. I really look forward to my weekly cleanouts so I can check out how all the rocks are doing. If I switch to the recharge method, I will only get to see my rocks every three weeks instead of every week. That would save me time going through them all, but I enjoy that time.
The other downside to the recharge method is that I don't get to remove rocks unless I can wash them off and inspect them. So rocks that may be ready to come out end up in the tumbler for up to two more weeks. This makes the rocks smaller and they take up room that could be used by fresh rocks. Ken, you said that you removed rocks from each batch. I assume that for at least the recharge batch you mean that you removed them at the end of the three weeks. I don't see how you could remove them earlier.
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tkvancil
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Post by tkvancil on Nov 6, 2014 9:53:04 GMT -5
Yeah, Rob, the ones I took out ready for 220 were taken out at the end of the three weeks. From both actually, I put off inspecting the cleanout rocks. I know what you mean about that time spent inspecting rocks. Sometimes I get to know almost every rock in the barrel and will often pick out the ones I have highest hopes for first. It's also nice to see progress week to week as well. I remember a couple plain Jane looking black and white pieces ... after a couple weeks some dendrites and translucent colors began to appear, very unexpected and cool. One member who recharges (can't remember who unfortunately) said that he picks the rocks out of the slurry and rinses leaving as much of the slurry in the barrel as possible. I make a big enough mess as is and think I'd be messier that way. LOL
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jamesp
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Post by jamesp on Nov 6, 2014 10:23:16 GMT -5
I cheat and have to look at the rocks too. I do pour the whole contents into a tray, and then pour the entire contents back into the barrel. Wash them down a bit for viewing pleasure, and then pour the water off and dump the heavier stuff back in. Ya gotta cheat. And pick out the duds, so justified. A real tumbler has to look at his rocks at least once a week. And yes, it is messy.
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Post by captbob on Nov 6, 2014 10:32:36 GMT -5
A real tumbler has to look at his rocks at least once a week. pffft They don't need me, and will do just what I'm wanting them to do without my holding their little rock hands. That's akin to saying a real baker will open the oven door several times while a cake is baking to see how it's doing. Call me when the timer dings. Or, in the case of rocks, whenever I get around to it. Other than in the grinding stages, excessive time is of no concern or importance.
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jamesp
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Post by jamesp on Nov 6, 2014 10:37:11 GMT -5
A real tumbler has to look at his rocks at least once a week. pffft They don't need me, and will do just what I'm wanting them to do without my holding their little rock hands. That's akin to saying a real baker will open the oven door several times while a cake is baking to see how it's doing. Call me when the timer dings. Or, in the case of rocks, whenever I get around to it. Other than in the grinding stages, excessive time is of no concern or importance. So you slept well on Christmas night?
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tkvancil
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Post by tkvancil on Nov 24, 2014 13:09:20 GMT -5
I don't have pictures this go round. Would only have been more of the same.
This round was with an 8 tablespoon charge of 80 grit. In the recharge barrel I did a much better job of "slurry management". By removing some and thinning with water it did not get overly thick leading to a "clunking" barrel. Tumble sounds were good the whole way through. For reference I removed 5/8 cup slurry and added back 1/2 cup water.
Each barrel started with 90.5 ounces of material. Seven ounces filler in each end of week 7. Six ounces filler end of week 8. Total of 103.5 ounces.
Cleanout barrel rough weighed 86.375 ounces at end of week 9. 17.125 oz. lost mass or .71 oz. per tbs. grit. Recharge barrel rough weighed 92.375 ounces at end of week 9. 11.125 oz. lost mass or .46 oz. per tbs. grit.
It seems that the cleanout is out grinding the recharge. Perhaps the mud in the slurry is acting as a cushion. Someone suggested that as a possibility along the way.
Comparing the last phase with 6 tbs. grit in each barrel and this current phase with 8 tbs. per barrel ... Cleanout w/6 tbs. lost 13.7 % mass , Cleanout w/8 tbs. lost 16.5% mass Recharge w/6 tbs. lost 10% mass , Recharge w/8 tbs. lost 10.7% mass
It seems that more grit provides more grinding. This makes sense to me but I would think that there is a breaking point. For instance say 12 tbs. of grit gets used up in a week and provides for X amount of lost mass. Where as 14 tbs. grit gets almost used up and provides for the same amount of lost mass. Pure conjecture.
The biggest reason for this experiment is to satisfy my own curiosity. Looking for the fastest method for the way I do things. Don't currently have enough rotary capacity to keep up with the UV18 mom got me for my B-day. I am beginning to be convinced, again at least for how I do things, that cleanout is better. At this point I'm not ready to give up on the experiment. Since phase 1 had over full barrels and phase 2 had over thick slurry I will do at least one more phase. Started this next phase with 10 tbs. grit in each barrel. I will also take out more slurry attempting to match the level of liquid to the level in the cleanout.
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panamark
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Post by panamark on Nov 24, 2014 15:50:27 GMT -5
It seems that the cleanout is out grinding the recharge. That is what I would have guessed. I was surprised some others thought otherwise, so thanks for running the experiment. Maybe someday I will run some more experiments on this too and post results.
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Post by Jugglerguy on Nov 24, 2014 17:07:29 GMT -5
I have always felt that my rough grind could use the most improvement. It just takes so darn long! I have always wondered which was better because some people from both camps are equally insistent that their method is better. I'm glad to have someone finally do a good, scientific test to find out once and for all which is better. Thanks a bunch for doing this, Ken.
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jamesp
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Post by jamesp on Nov 24, 2014 19:30:00 GMT -5
I am surprised. Thinking that a healthy slurry to carry the grit would have been most efficient. In my mind and seat of the pants experience I thought the other way, but never did measurements and have zero documentation. It is important. because the coarse grind is the most torturous part of tumbling. If I have a watery slurry I do not have much wear on my rocks. But if you start with a waterery slurry and have a medium slurry at the end of a week then job is getting done. no doubt. I will say if you do not get a dirty slurry after a week the job is not getting done. dirty slurry = wear on rocks, that is pure fact. If it gets dirty every 7 days then all should be well. I think most rotary instructions say to do a clean out. Cool experiment. but important, any way to better the coarse grind is great news.
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tkvancil
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Post by tkvancil on Nov 26, 2014 12:31:12 GMT -5
It seems that the cleanout is out grinding the recharge. That is what I would have guessed. I was surprised some others thought otherwise, so thanks for running the experiment. Maybe someday I will run some more experiments on this too and post results. I wasn't sure what to expect. If you ever do decide to do your own test I'd be very interested in the results.
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tkvancil
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Post by tkvancil on Nov 26, 2014 12:39:14 GMT -5
I have always felt that my rough grind could use the most improvement. It just takes so darn long! I have always wondered which was better because some people from both camps are equally insistent that their method is better. I'm glad to have someone finally do a good, scientific test to find out once and for all which is better. Thanks a bunch for doing this, Ken. Rob, I know what you mean about how long it takes. Luckily I'm patient for the most part. One more round of this test just for confirmation. After that I'm going to keep increasing grit. I want to find out when all the grit stops being used up and if more grinding occurs along the way. Been glad to do this.
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tkvancil
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Post by tkvancil on Nov 26, 2014 12:49:07 GMT -5
I am surprised. Thinking that a healthy slurry to carry the grit would have been most efficient. In my mind and seat of the pants experience I thought the other way, but never did measurements and have zero documentation. It is important. because the coarse grind is the most torturous part of tumbling. If I have a watery slurry I do not have much wear on my rocks. But if you start with a waterery slurry and have a medium slurry at the end of a week then job is getting done. no doubt. I will say if you do not get a dirty slurry after a week the job is not getting done. dirty slurry = wear on rocks, that is pure fact. If it gets dirty every 7 days then all should be well. I think most rotary instructions say to do a clean out. Cool experiment. but important, any way to better the coarse grind is great news. I had thought that recharging might work better because of the broken down grit left in the slurry. Finer grits don't grind off much but do some work. When doing a cleanout I think water is the wild card. Have to have just enough to get grit sticking to the rocks but not so little that the slurry gets overly thick. When I first started using these 6 pounders I was cleaning out every 5 days. Never had any grit left in the barrels. They seem to be very efficient. I went to the 7 day cycle because every 5 left me pressed for time when a cleanout fell on a work day.
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