Brian
fully equipped rock polisher
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Post by Brian on Jan 21, 2021 21:06:09 GMT -5
Welcome to the forum from South Dakota!  Thank you for taking the time to make this your first post...of many I hope! It's kind of exciting in a way for me to see the calculations. I have a tendency to forget that while variables are fluctuating within a given scenario, they can be tracked and accounted for... (That makes sense in my head! LOL) Greetings back from Virginia! No problem at all taking the time. I hope to do some controlled experiments to start verifying certain interactions of tumbling variables, but that will mean I need more than one 3lb barrel! Planning to get the QT66 once it's back in stock but it seems COVID really hit Lortone hard. One thing I have begun to experiment with is recording tumbling sessions and tracking changes in loudness over time; will make a thread on that once this load finishes. As far as the original topic, I've started logging things in JSON format so I can be a bit more customized with log format. For instance, the overall object would be for a given tumble, with sub-objects for each stage or barrel change. Once I start my calcite tumble I'll post an example here. I certainly hope you keep us posted on your experiments! What are you using to measure the loudness? I'm embarrassed to admit the last programming language I used. Let's just say, it's been a few years. I'd love to see some screenshots of your logbook. The organization structure sounds like a good way to arrange it. I debated using a start-to-finish structure for record keeping, but instead opted to a numbered system that references each stage by number. Until the kids get bored with the tumbling, I doubt we will have many single-spacies tumbles, which means we will often have rocks that move on while others stay behind. |
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rrod
having dreams about rocks
Member since December 2020
Posts: 72
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Post by rrod on Jan 21, 2021 21:49:44 GMT -5
I certainly hope you keep us posted on your experiments! What are you using to measure the loudness? I'm embarrassed to admit the last programming language I used. Let's just say, it's been a few years. I'd love to see some screenshots of your logbook. The organization structure sounds like a good way to arrange it. I debated using a start-to-finish structure for record keeping, but instead opted to a numbered system that references each stage by number. Until the kids get bored with the tumbling, I doubt we will have many single-spacies tumbles, which means we will often have rocks that move on while others stay behind. I've got a calibrated mic (UMIK-1) feeding into RoomEQ Wizard. I position the mic just by the guide on the idler shaft of my A-R1. Here's my current run with 500 Al 2O 3.
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Benathema
has rocks in the head
God chased me down and made sure I knew He was real June 20, 2022. I've been on a Divine Mission.
Member since November 2019
Posts: 703
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Post by Benathema on Jan 21, 2021 23:08:31 GMT -5
"This is sort of a tangent but also related. I converted tablespoons to cups years ago, and throw 1/2 cup of grit or polish in the 6lb barrel, 1 cup in the 12lb barrel, 2 in the 20lb, and 4 in the 40lb. It seems close enough and works well. What would happen if we went overboard or underboard? Has anyone ever tried it to see what happens? I'm going to take a guess, but this is only a guess. If batches usually are just right after a week (a timing which I kind of like also) wouldn't using too little grit merely mean the batch would get done sooner because the grit would be worn out sooner? Or would the grit still "last" a week just a lot less grinding would happened?" Is the reverse true? What if I threw in 2 cups (twice normal) of coarse grind grit in a 12lb barrel? Would it grind twice as much rock off in a week so would not be a waste of money? Or would the grit last longer than a week? I've taken to thinking that each grit particle (grain) is capable of removing a certain amount of material. This in part is why we chose coarser abrasives for the initial stages. A bigger particle can take a bigger "bite" out of the material, but it also sticks around longer before being pummeled to oblivion. I'd say adding more or less would definitely have an impact towards how much grinding gets done. The extreme ends of the scale, say 1 grain of grit, would do nothing, and adding too much could restrict tumbling motion and/or create a slurry too thick to tumble. Since were in the business of not throwing out good grit, nor really wanting to add an extra process to recover it, we have to strike a balance in between. The Goldilocks zone of grit additions. Many folks do recharges exactly for this reason. Furthering that, prior posts by jamesp mention thinning the slurry out when doing recharges. In terms of using volumetric measurements for the grit we run into the problem of particle packing in that volume (density). 1 cup of 36 SiC would not weigh the same as 1 cup of 220 SiC. So how much are we really adding, and what does "how much" even mean? We're adding a volume, which will add some approximate x number of grit grains per grit metric, but we don't make apples-to-apples comparisons like, "how much material is removed using 10^4 grains of 36 grit versus 10^4 grains of 220 grit?" I'm very strongly considering weighing the abrasives rather than eyeballing volumetric measurements. To this end I could better control how much I'm adding exactly, and better understand how long a 25 lb bag of grit will last. Adding just that little bit extra "for good measure" every time adds up to real money over the course of a year. I have logged masses of the large stones I've tumbled, but that's just a weekly inspection. Within a specific grit range, the material removal rate appears constant, add some x tbsps of y grit and see z amount of material loss. I highly suspect that what is going on in the barrel is not a linear material removal rate, but rather, some exponential decay curve. Once a slurry is developed or generated, removal rate is quick, but then tapers down as the grit particles wear down. It doesn't approach a 0 material removal rate though, there is still some natural abrasion between the rocks, but whatever slope that is after the grit is gone is much shallower. I bet, and actually know, from my experience and others here that the grit does most of its work in the first 3-4 days. You can feel it in the rocks, even if the grit just got used up, they have a roughness to them. Continuing to run them to day 7 without a recharge leaves them much smoother. |
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jamesp
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Post by jamesp on Jan 22, 2021 6:44:46 GMT -5
You guys mentioned attaching SiC together for a time release. Perhaps bound in glass.
Consider the 5" grinding wheels broken into ~1 inch chunks.
The SiC 50 grinding wheels are rated at 5000 rpm.
Such high speeds requires the SiC 50 to be 'glued' together very well to prevent the wheel from coming apart causing serious injury.
They may have been fused together using heat and pressure ? Whatever they did, these wheels were hard to break.
The chunks lasted 2 to 3 weeks in step 1 and did a fantastic job of shaping Mohs 7 rocks.
It became apparent that 3 weeks worth of SiC(a triple dose by weight)could be added to the barrel.
So there was a large dose of SiC when the loose particles and chunks were added together.
The biggest problem(IMO a good thing) was that the chunks caused severe wear on the barrels.
If the barrels are wearing fast then the rocks are wearing fast !! A good thing if you build wear proof barrels.
And like SiC grinding wheel chunks, raw SiC #2(3/8" chunks) #4(BB sized) and #8 eats barrels(and rocks) rapidly too.
The final outcome is simple, it takes wear proof barrels to reliably increase grinding rates on rocks in step 1.
The best way to save time in step 1 is to use aggressive abrasives in the optimum doses and run at optimum speeds.
It is a very simple relationship.
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Wooferhound
Cave Dweller
Lortone QT66 and 3A
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Post by Wooferhound on Jan 22, 2021 7:16:41 GMT -5
I've got a calibrated mic (UMIK-1) feeding into RoomEQ Wizard. I position the mic just by the guide on the idler shaft of my A-R1. Here's my current run with 500 Al 2O 3.
Now you got my attention. I provide Sound Systems all over the North Alabama area. Interesting concept but not very useful in my opinion. Might work to some extent in stage 1 but almost useless in later stages. When I tumble I like for the Slurry to get very thick at the end of a run and can even completely stick together leaving only motor noise. This assures that as much grinding is being done as possible in the week that it runs. Would be interesting to get frequency analysis too and see how the High and low frequencies change.
I have never written anything down in my few years of tumbling with 3 barrels rolling. I only got confused about the contents once but everything came out fine. For a while I thought that a Post-It note for each barrel would be fine but I never actually did it.
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jamesp
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Member since October 2012
Posts: 36,606
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Post by jamesp on Jan 22, 2021 7:38:24 GMT -5
jamessp, I had posted this recently in another thread, and wondering what you think? "This is sort of a tangent but also related. I converted tablespoons to cups years ago, and throw 1/2 cup of grit or polish in the 6lb barrel, 1 cup in the 12lb barrel, 2 in the 20lb, and 4 in the 40lb. It seems close enough and works well. What would happen if we went overboard or underboard? Has anyone ever tried it to see what happens? I'm going to take a guess, but this is only a guess. If batches usually are just right after a week (a timing which I kind of like also) wouldn't using too little grit merely mean the batch would get done sooner because the grit would be worn out sooner? Or would the grit still "last" a week just a lot less grinding would happened?" Is the reverse true? What if I threw in 2 cups (twice normal) of coarse grind grit in a 12lb barrel? Would it grind twice as much rock off in a week so would not be a waste of money? Or would the grit last longer than a week? For finishing steps in a vibe I have reduced the doses to 1/5 of the manufacturer's suggested dose and seem to get faster polish times. As if it takes longer to break down larger doses - makes sense. Use only what is needed to get to polish. The Lot-O came out more recently and it uses smaller doses than the older vintage vibe recommendations. Rotary may not work the same way... As far as step 1, it is a totally different animal. More more more. The more abrasives the better IMO Bob. As long as the batch is not hindered in movement. With a good slurry, abrasive(SiC) particle distribution can be one particle per square mm, one particle per each square 1/4 inch, one particle per each square 1/2 inch, etc etc. It would not be too difficult to calculate the approximate surface area of 12 pounds of rock and the amount of say SiC particles in a cup of SiC 46. One could easily calculate the surface are of 12 pounds of one inch marbles, easy enough and should give a good surface area approximation for rocks. Looking for the quantity - particles/sq. cm. for instance. Why not have 10-15 particles per square centimeter ? Old tumbling instructions rarel suggest adding a slurry additive, they always start you with water which likely limits the amount of coarse SiC. Slurry can carry and distribute much more coarse abrasive. Those are my thoughts. |
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Brian
fully equipped rock polisher
Member since July 2020
Posts: 1,512
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Post by Brian on Jan 22, 2021 7:47:30 GMT -5
I certainly hope you keep us posted on your experiments! What are you using to measure the loudness? I'm embarrassed to admit the last programming language I used. Let's just say, it's been a few years. I'd love to see some screenshots of your logbook. The organization structure sounds like a good way to arrange it. I debated using a start-to-finish structure for record keeping, but instead opted to a numbered system that references each stage by number. Until the kids get bored with the tumbling, I doubt we will have many single-spacies tumbles, which means we will often have rocks that move on while others stay behind. I've got a calibrated mic (UMIK-1) feeding into RoomEQ Wizard. I position the mic just by the guide on the idler shaft of my A-R1. Here's my current run with 500 Al 2O 3.
Very cool to see the sound profile of that run. I could see how that could be a good indicator for when the grit is exhausted in stage 1. Given the time over which the run occurs, it would probably be difficult to identify a 1 dB drop, or when you may have an inflection point in your curve that signals a change between grit-on-rock grinding to rock-on-rock grinding. Like Wooferhound pointed out, it would be interesting to see the frequency response over time as well. |
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rrod
having dreams about rocks
Member since December 2020
Posts: 72
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Post by rrod on Jan 22, 2021 7:48:26 GMT -5
I've got a calibrated mic (UMIK-1) feeding into RoomEQ Wizard. I position the mic just by the guide on the idler shaft of my A-R1. Here's my current run with 500 Al 2O 3.
Now you got my attention. I provide Sound Systems all over the North Alabama area. Interesting concept but not very useful in my opinion. Might work to some extent in stage 1 but almost useless in later stages. When I tumble I like for the Slurry to get very thick at the end of a run and can even completely stick together leaving only motor noise. This assures that as much grinding is being done as possible in the week that it runs. Would be interesting to get frequency analysis too and see how the High and low frequencies change.
I have never written anything down in my few years of tumbling with 3 barrels rolling. I only got confused about the contents once but everything came out fine. For a while I thought that a Post-It note for each barrel would be fine but I never actually did it.
Do you mean in a vibe? I could see that. In a rotary, even at later stages the dominant component is the tumble if you've got the mic positioned correctly. But you are right that my main hope is that I might shave a day or two off of each 80 grit run by assessing when the grit has stopped making swift progress. I'll note that I'm also making an actual recoding at the same time, so I can check the last hour or so of progress and see how things like peak levels and the spectrum have changed as well. This has shown a strong tone at ~120Hz (1st overtone of mains hum?) but it doesn't really affect overall loudness, is constant anyway and thus ignorable, and is easy enough to notch filter out. |
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rrod
having dreams about rocks
Member since December 2020
Posts: 72
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Post by rrod on Jan 22, 2021 8:16:59 GMT -5
I've got a calibrated mic (UMIK-1) feeding into RoomEQ Wizard. I position the mic just by the guide on the idler shaft of my A-R1. Here's my current run with 500 Al 2O 3.
Very cool to see the sound profile of that run. I could see how that could be a good indicator for when the grit is exhausted in stage 1. Given the time over which the run occurs, it would probably be difficult to identify a 1 dB drop, or when you may have an inflection point in your curve that signals a change between grit-on-rock grinding to rock-on-rock grinding. Like Wooferhound pointed out, it would be interesting to see the frequency response over time as well. Once I get my next run going I hope to get a more continuous recording going which should let me look at that. These past two tumbles I've been experimenting and thus doing things like accidentally pressing stop and deleting files. As you both have suggested, my main goal is to make stage 1 go more quickly, which is a goal born out of the desperation of having only one small barrel to use. I need me one of them fancy tumbling cabinets. |
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Post by jasoninsd on Jan 22, 2021 8:31:02 GMT -5
rrod - Reading through a lot of people's posts, I've read a ton of excuses...I mean sound reasoning...for the purchase of new tumblers. I think the reason for "purely scientific purposes" is one of the better ones! LOL
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Brian
fully equipped rock polisher
Member since July 2020
Posts: 1,512
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Post by Brian on Jan 22, 2021 9:22:50 GMT -5
Very cool to see the sound profile of that run. I could see how that could be a good indicator for when the grit is exhausted in stage 1. Given the time over which the run occurs, it would probably be difficult to identify a 1 dB drop, or when you may have an inflection point in your curve that signals a change between grit-on-rock grinding to rock-on-rock grinding. Like Wooferhound pointed out, it would be interesting to see the frequency response over time as well. Once I get my next run going I hope to get a more continuous recording going which should let me look at that. These past two tumbles I've been experimenting and thus doing things like accidentally pressing stop and deleting files. As you both have suggested, my main goal is to make stage 1 go more quickly, which is a goal born out of the desperation of having only one small barrel to use. I need me one of them fancy tumbling cabinets. I hear you on that one (pun fully intended). I have a Lortone 33B with two 3-lb barrels which makes for a slow process. A vibe just arrived a few days ago but I haven’t set it up yet. Based on sound alone, I am fairly certain that my rough grit has broken down at least since yesterday, but I won’t clean it out until tomorrow at day 7 just to make sure it had sufficient time. The waiting does give plenty of time to think about things and come up with crazy new ideas to talk about here. |
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Brian
fully equipped rock polisher
Member since July 2020
Posts: 1,512
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Post by Brian on Jan 22, 2021 9:27:13 GMT -5
rrod - Reading through a lot of people's posts, I've read a ton of excuses...I mean sound reasoning...for the purchase of new tumblers. I think the reason for "purely scientific purposes" is one of the better ones! LOL This made me laugh because I was thinking of telling my wife the new Lot-O will actually be very helpful for making her new concrete countertop. I was thinking of clamping it to the mold to create a vibrating platform to remove bubbles. Sounds like a reasonable use, right? |
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Post by jasoninsd on Jan 22, 2021 12:56:02 GMT -5
rrod - Reading through a lot of people's posts, I've read a ton of excuses...I mean sound reasoning...for the purchase of new tumblers. I think the reason for "purely scientific purposes" is one of the better ones! LOL This made me laugh because I was thinking of telling my wife the new Lot-O will actually be very helpful for making her new concrete countertop. I was thinking of clamping it to the mold to create a vibrating platform to remove bubbles. Sounds like a reasonable use, right? For that purpose I would think you'd need a at least UV-10 or even a UV-18 in order to fully remove all gas pockets in the concrete. LOL  |
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Brian
fully equipped rock polisher
Member since July 2020
Posts: 1,512
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Post by Brian on Jan 22, 2021 15:20:32 GMT -5
This made me laugh because I was thinking of telling my wife the new Lot-O will actually be very helpful for making her new concrete countertop. I was thinking of clamping it to the mold to create a vibrating platform to remove bubbles. Sounds like a reasonable use, right? For that purpose I would think you'd need a at least UV-10 or even a UV-18 in order to fully remove all gas pockets in the concrete. LOL So what I am hearing you say is an upgrade is in order?!? 😉 Or at least balance out the load, so to speak by having one on each side? |
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Post by jasoninsd on Jan 22, 2021 16:56:02 GMT -5
For that purpose I would think you'd need a at least UV-10 or even a UV-18 in order to fully remove all gas pockets in the concrete. LOL So what I am hearing you say is an upgrade is in order?!? 😉 Or at least balance out the load, so to speak by having one on each side? How can you even think about stabilizing something without three points of contact...so let's be realistic, a third one is probably going to be necessary to complete the project correctly!  |
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,606
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Post by jamesp on Jan 23, 2021 0:38:50 GMT -5
I've got a calibrated mic (UMIK-1) feeding into RoomEQ Wizard. I position the mic just by the guide on the idler shaft of my A-R1. Here's my current run with 500 Al 2O 3.
Now you got my attention. I provide Sound Systems all over the North Alabama area. Interesting concept but not very useful in my opinion. Might work to some extent in stage 1 but almost useless in later stages. When I tumble I like for the Slurry to get very thick at the end of a run and can even completely stick together leaving only motor noise. This assures that as much grinding is being done as possible in the week that it runs. Would be interesting to get frequency analysis too and see how the High and low frequencies change.
I have never written anything down in my few years of tumbling with 3 barrels rolling. I only got confused about the contents once but everything came out fine. For a while I thought that a Post-It note for each barrel would be fine but I never actually did it.
This was my finding woofer. A good slurry quiets the rotary to a low pitch grinding sound as opposed to a water slurry making a higher pitch rattling sound. Run glass in straight water for an hour at high rpm and it will be bruise damaged. So it is mandatory to add slurry thickener and maintain it's viscosity thru out the entire run. To maintain a consistent slurry viscosity I pour off some slurry and add water about every 2 to 3 days. The sound of the barrels will let you know if the viscosity is correct. But it is safer to check the viscosity every 2 days. With glass at only Mohs 5, SiC lasts about twice as long when running glass as SiC lasts with Mohs 7 rocks of equal size. A large rock in the batch reduces the life if SiC a large amount which equates to a faster grind. Some tumbled glass using protective clay slurry. Upper right tumble has small bubbles causing the spots.  From same batch. Example of bruises from watery slurry in top 3 tumbles visible in glare. Lower 3 were re-run starting at 220 grit to shave of bruises.  SiC 16 SiC 60 in rotary for 10 days total, AO 220 AO 500 AO 14,000 in vibe for 7 days total. 5 steps. clay in rotary, sugar in vibe.  Wear resistant 8 inch HPDE barrels to handle super coarse SiC. The 6 inch PVC barrels last a long time with finer abrasives. Front shafts are high speed for coarse grind and rear shafts are slow speed for finishing/polishing.  |
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jamesp
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Member since October 2012
Posts: 36,606
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Post by jamesp on Jan 23, 2021 1:08:29 GMT -5
rrod - Reading through a lot of people's posts, I've read a ton of excuses...I mean sound reasoning...for the purchase of new tumblers. I think the reason for "purely scientific purposes" is one of the better ones! LOL This made me laugh because I was thinking of telling my wife the new Lot-O will actually be very helpful for making her new concrete countertop. I was thinking of clamping it to the mold to create a vibrating platform to remove bubbles. Sounds like a reasonable use, right? The standard issue wife is smarter than all of us and will be well aware of why purchases are being made. Not if, but when she senses deception the only tumbler in the house will be you shaking your Christmas stocking full of coal. |
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jamesp
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Member since October 2012
Posts: 36,606
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Post by jamesp on Jan 23, 2021 1:28:07 GMT -5
Choose experiments carefully, it takes many moons to get experimental tumbling results.
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jamesp
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Member since October 2012
Posts: 36,606
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Post by jamesp on Jan 23, 2021 1:35:28 GMT -5
Maybe a brilliant mathematician ( Brian ?) will show up on RTH to derive a formula for rock removal(grams)/time(days) in step 1 coarse grind using a dimensional analysis formula by entering quantities for variables such a barrel rpm, size of SiC grit, diameter of barrel, amount of SiC grit, viscosity of slurry as compared to water, percent barrel fill, ratio of barrel length to barrel diameter, clean out rate, temperature, octagonal verses round barrel, etc etc. Complicated processes with lots of variables are often analyzed for performance by using dimensional analysis. Basically you are entering numbers for each variable and multiplying them together to get a final performance number be it high or low. Was going to stop lurking after my first labradorite tumble finishes up in a month, but there’s math to be done! The underlying theory and more efficient algorithms are based on the Buckingham π theorem, linked in that same article on dimensional analysis. Let’s take a simple example with four variables (and their units): t = tumble time (s) h = Knoop hardness (kg*m^-1*s^-2) r = amount of grit (g) a = surface area of rock (m^2) The nitty gritty (pun intended) is left for the reader, but the end result of the theorem is that you end up with the following relationship for *this choice of variables*: t^4 = C * h^2 * a * r^-2, where C is some constant You can see already some implications, some interesting and some obvious, of this tumbling model: 1) More grit = less time 2) Harder material = more time 3) Tumbling time is maintained by tracking total grit with the Knoop hardness 4) More surface area (which here is proxy for total amount of rock) increases tumbling time, but not as quickly as increasing hardness 5) Increasing grit lowers the tumbling time much more quickly relative to decreasing the amount of rock There’s lots of nuance in picking the important variables, and adding a lot of variables means a *much* more complicated relationship you have to figure out (you don’t just get a constant to deal with). Also sometimes what you get is total garbage because you’ve missed some important variable. For instance, here we're missing the viscosity of the slurry, the barrel speed, etc. Maybe for another day! Watching with interest rrod. In my history of experimentation the least expected parameter was they most important influence on rotary tumbling rates and rock protection. That would be both the viscosity and the composition of the (colloidal clay) slurry. |
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Brian
fully equipped rock polisher
Member since July 2020
Posts: 1,512
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Post by Brian on Jan 23, 2021 12:08:36 GMT -5
This made me laugh because I was thinking of telling my wife the new Lot-O will actually be very helpful for making her new concrete countertop. I was thinking of clamping it to the mold to create a vibrating platform to remove bubbles. Sounds like a reasonable use, right? The standard issue wife is smarter than all of us and will be well aware of why purchases are being made. Not if, but when she senses deception the only tumbler in the house will be you shaking your Christmas stocking full of coal. My wife is great. She seems to only hear, “Yes, Dear” and “Anything you say.” My memory must be going because apparently I say those things much more than I remember. |
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