I've got a theory. What causes grit to wear down the rocks is friction, which is to say pressure + movement. The tumbling action creates friction as rocks slide past and roll over top each other. (If you overfill the barrel and the rocks cannot move freely, the grit and water splashing around inside the barrel will not grind down the rocks.) When two rocks are on a collision course -- and there is grit stuck to the rocks -- the friction occurs between the rocks and the grit. The more pressure, the more friction, and the more grinding action. It's like pressing harder with a piece of sandpaper. The amount of grit probably impacts the amount of pressure, and thus the amount of frictional force. If there is too much grit, the tumbling energy will be absorbed by the grit, as the grit is squeezed out from between the rocks without really digging into the surfaces of the rocks. Similarly, the more pieces of grit that are stuck between two rocks, the less pressure there will be as between the surface of the rocks and a specific piece of grit. (It's an issue of pressure decreasing with surface area, like lying on one nail vs. a bed of nails.) I suspect that the ideal amount of grit is just enough so that there is a very thin layer of grit between the rocks. With a thin layer, the grit will not cushion the tumbling action, and the pressure / friction will not be dispersed excessively over too much surface area. Too much grit may also result in the grit being broken down primarily by being ground into other pieces of grit vs being scraped against the surface of a rock. You could think of this as the rocks grinding down the grit, as opposed to the grit grinding down the rocks. Grit breaking down grit is counterproductive, which could be why less can be more, as suggested by your experiment. For anyone who has made it this far, you might as well tell me what you think of my theory. I am not overly attached to it, so feel free to agree, disagree, or improve upon it. Thanks!
That's a better theory than what I came up with and I think it makes a lot of sense. I like your bed of nails example, that really makes it clear to me. I'm also really interested in what others that might have more experience in this area might think. Thanks for taking the time to write that up!
Seams reasonable. There’s just too many variables to be sure what’s going on. Could a more watery slurry suspend the grit and cushion it thus preserving it. Or does it tumble faster breaking the grit even faster? Does the rate at which the slurry thickens affect speed at which the grit breaks down? Does a thicker slurry apply pressure to the grit or clog the sandpaper? Certain rocks can absorb more H2O. Is hard water better for grinding, worse for polishing .Temperature is always a factor. It would clinical trials to be definitive 😂. You guys broke it down pretty good though. Probably better than it should. Fun to think about. He does a good job at taking your mind off things for a while. Happy Holidays
Really pleased to have found you. I’m brand new to rockhounding and your channel has been outstanding in helping me learn about my new hobby, thank you and happy rockhounding 🎉🎉🎉
Interesting. I know you said you weren't going to do it, but redoing the experiment with 1 and 2 tablespoons of grit might surprise you further. I would also redo the 3 spoon test two more times and look at the mean and variance across 3 samples of the 3 tablespoon test. If the result is highly variable, you have to wonder what factor is causing that to happen.
I thought about doing this for a second week, but weighing all those rocks just takes so long. I figured with four barrels coming out pretty much the same, I had pretty good evidence. I am curious about using a smaller amount though. I don't plan to redo this experiment anytime soon, but maybe some day. I have a couple other experiments planned.
Yes! I agree! I'd love to see this run with less grit...if successful, it could really save some money in the long run. I've been running my first 2 3lb tumblers for 4 weeks now, Saturday is my day to peek inside, rinse and add fresh water and grit. Last time i added 4 Tbs. in like you do, but this time I'll put just 3 based on this outcome! Thanks for doing such great research....and looking forward to more😊
@@MichiganRocks Hey Rob - judging by the numerous requests, your fans are on the edge of their seats on this optimal-number-of-tbsp mystery. I definitely hear ya on the time limitations for experimentation, though - you have to pick and choose and prioritize your time or this could easily turn into a Master's thesis project. But maybe you could reduce the weighing/sorting/matching step by using that "Large Ceramic Media", from Kingsley North or The Rock Shed, as the target "rocks". There are other larger size ceramic tumbling media available from industrial suppliers that might be a better stand-in for target rocks (e.g. a "1" x 1" V-Cylindrical" material from McMaster-Carr). This would reduce the effort to counting the pieces of ceramic media and weighing the the whole batch at once.
Hello. I started tumbling in January of this year based on your videos. However, your device and mine are different, so I created a form that is suitable for my method. Your video was helpful, thank you. My device Rotating tumbler: KT-6808, KT-245 (approximately 3 times the capacity of KT6808) Vibrating tumbler: SP-B10 (the capacity of KT-245 is just right) #60/90~#500(+borax) No media used In KT-6808, there were 3 large spoonfuls of undigested grid, so I used 2 spoonfuls after that. KT-245 is three times that. #1000, 3000 : using polishing media #Polishing :using polishing media, compound and borax I manage these items using EXCEL, including the equipment used, date, water volume, grid volume, etc. I'm looking forward to your future videos. From Japan
Very well planned and executed experiment that's quite relevant to the tumbling community! My guess/theory is that you basically have competition between grit breaking down rock and grit breaking down grit. Above 3 tbsp, the grit breaks down the grit faster than it breaks down the rock. I'd guess that if you did another set of experiments starting at 0.5tbsp and going up to 3, you'd see the rise you expected here, and then the weight loss plateaus like you observed here. I'm not saying you have to do this experiment, but it might help explain what's going on a little better. Great video!
That's an interesting theory. I hadn't really thought of the grit breaking itself down. I should redo this with less grit, but I'm not planning to right now. I have a couple other experiments I want to try first.
Thank you Rob! I’ve been tumbling for close to three years now and I am still learning great info from you. Your detailed videos are greatly appreciated.
It is really cool that you did this experiment and had the "grit" to report the results to everyone even though it didn't turn out the way you expected.:-)
I love this video. I love the mathematic set up and rigor. I am impressed by how information rich it is without being dense. I really appreciate how much insight you have given into the hobby of rock tumbling, valuable for spectators and enthusiasts alike. You really have the rock rizz.
I would love to see more of these types of experiments. I also wonder if more or less water would have played a significant role. I also wonder about the polish stages. 6 tablespoons of polish seems like a lot but I’m following Lortones guidelines.
I have a few more experiments planned. I hope to have the recording of the second part of this one done today. Then there are three others I have in mind.
Love that you're rocking the Michigan University shirts, too! My boss, Raymond Greene went there to be an Optometrist!! Lol back in like the 80s though. You definitely look younger than him 😂😋
LOVE how you tried to keep everything the same, down to the weight of the rocks! This channel is a wealth of knowledge! I've wondered myself recently if the amount of water is critical to grinding/polishing efficiency too. I'm very new to polishing rocks, finished one small batch with a nice glossy finish (not perfect but shiny for my 1st attempt). Did the same process with the last batch but they didn't take the shine like the others, the water/cerium oxide slurry mix was not thick at all and guessed that was why. I understand it should be thick almost like a paste. I've got them back on now with slightly less water and gave them another scrub, I've been scrubbing with ivory soap in between stages and keeping things very clean, not to cross contaminate grits.
I plan to test water amount in a future experiment. I can tell you that the slurry definitely does not have to be thick like paste. Most of my slurries are pretty watery but I have a lot of rock dust after I dry out my slurry to dump in the garbage.
I would be very interested to see the results of repeating the experiment with 1 & 2 spoons of grit. I think we were all surprised with those results, maybe we could be in for an even bigger surprise!
Excellent video. The only explanation I'd have for the barrel, is that the extra grit provided cushioning in the first few days of the tumble. Really interesting. I use too much grit.
Hi, interesting experiment, thank you. I think your explanation is good. Perhaps we also need to consider the distribution of abarasion forces between the grains. The more grains there are between two rocks, the lower the stress on each grain and the lower the abrasion at that point.
I was given a Thumler's UV-18 (Industrial) with the appropriate rock approved bowl. I'd LOVE to see a video on tumbling with one of these or similar! I have no idea how much grit to use! I do remember you using a spray bottle to get all the rocks appropriately dampened though.
I don't have a tumbler like that, but I do have a Lot-O vibratory tumbler. You could watch my video on that as a starting point. ua-cam.com/video/hz2E0xJYEWY/v-deo.html I'd also suggest getting on the Rock Tumbling Hobby forums and asking for some advice there. There will be several people who use that exact tumbler and will be very willing to help you out. You could also just read some old posts and get the information that way. There should be lots of old posts on that very popular tumbler. forum.rocktumblinghobby.com
I made a couple videos when I first started making videos a few years ago. My friend designed it and asked me not to share the plans, but the videos show it pretty well. Homemade Tumbler: ua-cam.com/video/6qIcK2ZohGM/v-deo.html Tumbler Update: ua-cam.com/video/PAMOCc2BNJM/v-deo.html
New to lapidary and rock tumbling, about 8 months. I enjoy your videos and have learned a lot, thanks. Also thanks for doing this test. I have 2, 6 lb and 1, 12 lb Lortone tumblers. I also have 10 and 18 lb Thumler style vibratory polishers and this week I picked up a used UV-45 tumbler. All of my rock gets the first round in the rotary tumbler. For the 6 lb drums I have used between 3 and 6 Tsp of abrasive with equal results. The 12 lb drum has been 7-10 Tsp abrasive with equal results. Always tumble for a week. Early on I started adding Borax to all stages and I think it helps keep the abrasive in suspension and cutting better. It’s a cheap additive and I’ve always used it. My test on abrasive efficiency is to rinse the slurry after clean out and see how much grit I can detect. A white bucket will tell you how much or little is left after tumbling. All of my polishing after the coarse grit has been in the vibratory polishers. I feel I get a superior finish and I can cut the total polish time to a quarter to a third of the time of doing all stages in a rotary tumbler. Thanks again for sharing your knowledge and experience working and polishing rocks.
I also do almost all of my finishing in a vibratory tumbler. I bought one before my first batch was done, so I have very little experience finishing rocks in a rotary tumbler. Have you weighed your rocks after tumbling? It sounds like you're just checking to see if your grit has all been used up. When you say you had equal results with twice as much grit, are you just looking at the left over grit, or are you weighing the rocks to see how much was ground away? Also are your measurements in tablespoons or teaspoons? Tsp is the abbreviation for teaspoons, right? I was measuring in tablespoons.
@@MichiganRocks I stand corrected, I use tablespoons for measuring. I’ve never weighed my rocks throughout the tumbling process. Another UA-camr suggested checking the slurry for grit to see if there was excess after the tumble and that’s my indicator if I’m using enough or too much. I’m not a stickler for perfectly rounded stones, I often prefer the natural way I found it polish. I finish with 2 sizes of ceramic media to get into all of the nooks and crannies. I’ve done some large 3-4 pound Mexican crazy lace agates start to finish in the rotary tumbler with good results. I’m doing palm stone size pieces in the vibratory tumbler with excellent results. I’ve got some 4-5 inch pieces ready for the Thumler UV-45. My goal is to tumble and polish pieces in the 5-10 pound category. I’ve seen others do this with good results. Finding an affordable drum big enough is the challenge for this project.
I appreciate your thoughts and comments. As always, UA-cam is a wealth of knowledge for beginner rock hounds. The largest single tumble I’ve seen was a stunning piece of Mexican crazy lace agate that weighed 45 pounds if I remember correctly. The guy used a 65 quart tumbler and it took 6 weeks to finish. This gave me motivation to try it on a smaller scale in the 5-10 pound range. Having been a machinist in the past and a brother that has a machine shop, my mind is full of ideas to fabricate equipment to pull this off.
@@davidsommerfeld2955 I don't think it was quite that big, but I think I know exactly what video you're referring to. There's a tennis ball next to the rock in the thumbnail.
Great experiment and good results. I have been using 3Tbl and I’m glad to know it’s a good amount. Thank you, I bet it was fun and educational to be a student in your classes!
👏 Well done experiment. I've been using 2-1/2 tablespoons of 60/90. I think your logic of there is only so much contact area between the rocks so having more grit won't make a difference is valid. If a person goes two weeks instead of one between rinsing, maybe more grit is better. I prefer one week so I can inspect to see if any are ready for stage 2.
I agree with what you said about running them for two weeks. More grit might be better. But like you, I like to get any rocks that are finished out of the tumbler as quickly as I can so they don't get any smaller than necessary.
Thank you for all you do to spread the love of rocks! My family (me, especially I guess) have officially fallen down the rockhounding rabbit hole. Your well-produced videos have inspired many trips to the UP and helped us gear up, better understand, and process our treasures. It is obviously a labor of love, but also a lot of work. Thank you!
Great video! There is no better feeling than being surprised when your hypothesis is completely wrong. I love the scientific method. Everything was really well thought out. I have to say, though, I would really like to see if 1 or 2 tablespoons would yield similar results. Then the ratio you were looking to diplay would become beneficial. It won't cut down on tumbling time but definatly can prove potential cost savings in grit. You have great content. I can only imagine how much time and money I saved getting into this hobby by first watching your videos.
I wish I had included two tablespoons in my experiment. Even at the best ratio of grit to amount of material removed, I might still use more grit if more grinding happened. You also have to consider time and electricity. I'd be willing to be a little less efficient with my grit to get faster results.
Great experiment professor Rob. You do the hard work so we don't have to. Seeing as I have only one tumbler and only one barrel. You saved me at least 5 weeks. Thanks and I would watch any future experiments you might do. 😀
This is a great experiment ! I would have thought the same so that was a surprise to me too. I'm still learning doing the research on the products used and what the best ones are. I guess it's personal preference. With you experience in sure you've experimental with many products . I really enjoyed this and enjoy all your videos . Thank you! 😊
I probably haven't experimented with as many as you might think. I did a lot of reading before I started and found good suppliers right away. Since I liked the products I started with, I have just kept using them. There are a few that I have changed, but not many.
Wow, that was not the results i was expecting either. I think about the time you put in to the details of this by finding the similar weight rocks for each barrel. Not an easy task. Good information to know now when using my small barrels. Thank you for sharing!
I like it when you do stuff like this. Another interesting thing to try would be the time to no grit. What about 6 days with 3 tbls ? Is there still grit after 5 days? If it’s gone after 5 days, is there a worthwhile benefit to go the extra 2 days with just the slurry? Or could total tumble time be reduced by a lot by saving that extra time every tumble. Or maybe it just isn’t worth it to try and remember what day to check, as the whole checking every Sunday seems like a good plan to remember.
The grit breaks down over time, so each day there's going to be a little less grinding. You could take them out earlier and replace the grit and get done quicker. Or you could let them go longer and get a little more out of your grit. I think seven days for a tumbler going at the speed of mine is about right. The National Geographic tumbler is much faster and I think for that, four days or so is enough.
You make amazing and informative videos. I love the beautiful rocks you find and the tutorials on cutting, making jewelry and your experiments! I was just wondering today if the manufacturer recommended grit is really necessary. Think I will give 3 TBS a try. I am very interested in your cabinet full of tumblers. Did you make it yourself? Do the motors running the tumblers get hot? I run a small fan near my tumbler motors to keep them cooler. Have you made a video showing how you set up the tumbling mechanisms? Would love to see more! Thanks again for your awesome videos.
That big tumbler was designed by a friend of mine and I built it. The motor does get hot, which is why it's on top rather than inside the cabinet. That has been running pretty much nonstop for several years with no motor problems. Here are a couple more videos showing the tumbler in more detail: Homemade Tumbler: ua-cam.com/video/6qIcK2ZohGM/v-deo.html Tumbler Update: ua-cam.com/video/PAMOCc2BNJM/v-deo.html
Thank you for the information and links. We will explore this, nice set up and pretty quiet. I have 2 Loretone 33b and they are surprisingly quiet, but I love your set up!
Great experiment. I think what you ran into is a viscosity problem. You used excellent experimental design, holding all factors constant, but the viscosity of the water and grit solution probably changed significantly. Viscosity increased as you increased the concentration of grit. A more viscous solution will grind rocks slower because the velocity of the solution moving in the drum decreases because of the increase in viscosity. The friction thing is also pertinent in as much that as you increased the concentration of grit, there was significantly more friction (more viscosity created) between the grains of grit in the solution, again slowing the velocity of the tumbling solution in the drum. There was no detectable difference in the amount of grit present at the end because the grit ground itself as well as the rocks. Just a thought.
Thanks for your theories. I never really thought about grit grinding against itself until you and others pointed that out as a possibility. I'm not sure about your viscosity theory, though. There are people who add various things to their barrels specifically to create a thicker slurry. The most common things I've heard of are old slurry and clay, sometimes in the form of kitty litter. There is also a product called "Old Miser" that is a slurry thickener. The idea behind thickening the slurry is to make the grit stick to the rocks better. The grit can only work if it's between two rocks, not if it's setting on the bottom of the barrel.
I’ve always used 3 in my 3 lb. Who knew it would be optimal. Thanks for confirming. Could it be like a balloon won’t pop if pressed against many nails spaced closely. Push it against one nail and it will. Maybe the grit is doing the same thing to the stones? Too much grit to get a good grind? Crazy results I agree.
My friend Jonathan had the same theory. I let him watch the video early and asked him to put his thoughts in a comment. I pinned it to the top. I think you both have the right idea.
That's interesting. I almost never have grit left over. The exception is if I put too many really small rocks in the barrel. That almost always results in left over grit.
Only difference I can see is I use Thumler's barrels. Even on my larger barrels (12 and 15 Lb) it is 1 teaspoon per pound. I keep wanting to purchase a Lortone Machine just to see if the barrels make a difference lol@@MichiganRocks
@@11stefanj I have a small Thumler's tumbler and I didn't notice a difference in the way the barrels work. I just notice that the lids wear out really quickly on those little Thumler's tumblers.
Yes they do. I repair them with plexi and the repairs last years! I am going to have to revisit my grit amounts now. You really got me thinking here. @@MichiganRocks
I don't know what a timed viscosity test is. I can tell you that the slurries all looked pretty much identical. I guess that's not surprising since they should all have about the same amount of rock dust in them. The only difference would be the amount of grit in the slurry.
Great video! I have been having a hard time getting my rocks done for the later stages of tumbling. I have found myself that 4 tablespoons of 36/70 in a 3 pound barrel is too much even after one week. I want to ask a question though. Will you ever do a review of the Minisonic 4 pound vibratory tumbler? Please do a review if possible. I have had a rough time trying to get a hold of the Lot-o. I love your videos so much they have helped me come a long way. I went from using a National Geographic tumbler with horrible results, to a batch of rocks with an amazing polish and having 18 pounds of tumbling power! I hope you have a great day!
I wanted to do a review of that exact tumbler last winter. I wrote the company and asked them to give me one to review, but they never answered me. I have plenty of tumblers, so I'm not really interested in buying a fairly expensive tumbler that I don't need.
Now, that you have figured out the volume of the rocks lost in the initial course grit, it would have been nice to see if there were any issues with quality. I know you ran them once prior to starting this experiment, however, seeing them up close to see if there was a quality different would have been nice. To me, it is all about quality of the tumbled stone when it is done with the cycle, not about how much I can get done per cycle.
This is only the first stage, so the whole point is to grind as much rock as possible. It's the later stages where the quality matters. I did look at all the rocks to decide which ones that were done with the first stage. I didn't notice any difference in the quality at all.
My daughter bought a Tumblr for me, and I have been obsessed with looking for a stones at the beaches. I live in Southwest Michigan near pier Cove which is a nice beach to go to, but I wanted to know where I can find Agget and how to find them. I’m not having a lot of luck with the rocks. I’m picking up to tumble maybe I’m doing something wrong, but I have been watching all of your videos.
Lake Superior is the best place to find agates, but even there, they are very rare. When I do find one, it's usually tiny. People do find them occasionally in Lake Michigan too. There are a lot of other rocks besides agates that tumble well.
@@MichiganRocks I use the bags just cuz it's easier to clean a mesh bag of rocks in a bucket of clean water than to rinse a colander. But if I saw I had 3 tbsp of grit leftover I'd maybe try to reuse it.
I was very interested in your results. I'm thinking of replicating your method. I'll report my results in the spring as my tumblers are in the unheated barn in northern Ohio.
I'm new to rock tumbling. What tumbler would you suggest for me? I have been watching your videos and I am learning alot. Thank you for any and all info.
I like the Lortone 33B. It was my first tumbler. Check the description of this video for The Rock Shed and Kingsley North. They are my two favorite places to buy from.
Thanks to you, I know more about rock tumbling than someone should who does not own a tumbler. I was leaning toward the Lortone 33b but can not find them in stock. Is there other tumblers you would suggest? Or should I hold out?
I'd wait for a Lortone. I think Kingsley North and the Rock Shed both have a way to leave your information when they're out of stock. If one of them doesn't, you could always send an email.
Hi Rob! My husband bought me an Extreme Rebel 17 which is a 17 pound rotary tumbler. I’m wondering what your grit suggestion would be? Should I stick with 1 tbsp per pound and is that the same for all 4 stages? I’m currently using the Lortone 33B and Lot-O vibratory to finish but my hope is to tumble larger sized rocks requiring the larger barrel for the whole process. Thanks so much for the help and all of your videos!
That's what I would do, but I don't know what's best for that machine. As I said in this video, what I tested was pretty specific and won't necessarily apply to other rocks or other tumblers. I don't have tons of experience finishing rocks in rotary tumblers, so I might not be the best guy to ask. I'd suggest posting your question on the Rock Tumbling Hobby forums.
Great experiment! I'm wondering if more grit creates a higher shock absorbing slurry - so some of the energy that would be focused on rock-wearing is perhaps lost to the higher liquid viscosity (reducing tumbling impacts)? Would be interesting to go 3 tablespoons of grit and 3 tablespoons of Borax, and see if that roughly mimics the 6 teaspoon of grit results.
That's a possibility, but the slurries appeared to be the same. Since about the same amount of rocks was ground away in each barrel, I'd expect the slurries to be about the same too.
. . . thank you for.reading my concern. . . can i. use a cement mixer to tumble rocks assorted size using water, grit.is.imported in belize and.would be too.expensive to buy local. . . hope you reach back to me. . .
Rotary tock tumbler barrels are sealed up so that the water doesn't evaporate. I think it would be challenging to keep the rocks wet in a cement mixer. I also tumble them for weeks or months, nonstop. How much would it cost to run a cement mixer for that long?
Rob, Terrific experimental design and execution. Many questions came to mind during and after your presentation. Are seven days optimal? If it's true that no grit remained in any barrel after 7 days, it seems likely most or all grit would have been gone before 7 days. I tumble coins in rock and grit or titanium and grit, and I am most interested in tumbling effects on coins, so both my methods and objectives are different than yours. But I've found in a couple of experiments that weight loss, in both rock and coin, follows a power curve trajectory over time, so the most rock and coin are removed the first day, less the second day, little on the fifth day, and practically nothing on the 7th day. So I've shortened 1st step tumble to four days--but again, I'm most interested in wear on coins, not on rocks, and my entire methodology is different. Nevertheless, it seems like a study of tumble time might be useful. One of the things I thought of a few weeks ago was maybe starting with two Tsp grit on day one and adding a third Tsp on day four. Some will ask why not just end the tumble at four days. Well, I'm not convinced that presence of grit is the only factor affecting tumble efficiency, and that brings me to the second question. Does grit have an effect beyond interstitial grinding? In particular, I'm wondering if grit affects the aqueous medium, perhaps by changing surface tension, buoyancy, penetrating capability, and so on. Perhaps your seven days is closer to optimal for rocks not because any grit is present but because you're accomplishing other things in the last four to seven days for rocks that I don't see occurring with my coins. I've discovered some interesting things in the last three months. Titanium and sodalite is an excellent combo for copper and bronze pennies (hardness 3), which makes me wonder if such a combo could be more generally applied to hardness 3-4 rocks. Neither titanium nor sodalite loses much weight in the tumble, but the pennies see substantial weight loss. Over maybe 40 days of tumbling the large titanium hex nuts have lost less than 2 percent of start weight and the sodalite is at around 10 percent. I've looked at three densities of plastic beads (0.9, 1.2, and 1.8 grams per mL) and also compared polypro beads vs. HDPE chips. The plastic chips have given me interesting results and I am pursuing more expts. using the little plates (roughly 8 mm square). Coin wear is a complicated process due to the many factors involved (coin weight and composition, strike depth, cultural factors (there are differences in wear between U.S., Canada, and the U.K., possibly due to the way coins are stored, transported, exchanged, etc.), and so on. The work continues. Thanks for the terrific presentation!
I bought a National Geographic tumbler to do a review of because it's such a popular tumbler. One thing that's much different than my other tumblers is that it's very, very fast. I think it's too fast and has potential to damage the rocks, but it also grinds the rocks much faster. With that tumbler, I think four days is plenty. One of the biggest reasons I run my tumblers for a week at a time is so that I can do clean outs on the same day every week. My neighbor has a couple barrels running at my house and we both know that Sunday is tumbling day. There's nothing to keep track of on the calendar.
Hi @@MichiganRocks Yours seems like the best system for efficiency. I'm sure you could take the time to determine optimal tumble time based on rotation rate, rock type, grit type and weight, and so on, but that in itself would take time, and then scheduling for 5.5 days for barrel A, 3.7 days for barrel B, and 9 days for barrel C would become a logistical nightmare. You'd be setting your alarm to go off at 2:00 in the morning, change the barrel, go back to bed for 2 hours, change the next barrel, and so on. What a mess that would be! But others might benefit from knowing, for example, that 4 days of tumbling achieves, let's say, gives 82 percent of weight loss relative to 7 days in the tumbler. While my data indicate something like this may be true, it may nevertheless be better for the rocks to tumble that extra 3 or 4 day. Your objective is not weight loss, after all, but polishing the rocks. My suspicion is that polishing is essentially going on in parallel with coarse abrasion, and probably following a different timeline than coarse abrasion, so that shortening the run time brings you to a place where the rocks just aren't ready for Step 2, even if they otherwise meet your criteria for moving on. But I could be wrong. Maybe shorter run time will work for many rocks. It certainly works for coins, at least for the experiments I'm performing. I'm just going to come out and recommend you give titanium a try for your hardness 3-4 rocks. I am finding good metal removal on my copper/bronze coins, but coin wear after tumbling in titanium is less severe and more natural than I find after tumbling in standard quartz and silicon carbide grit. Something similar could happen if you try titanium on rock: good coarse removal but better polished stones after Step 1. To wear 100 g of pennies I typically use 300 g sodalite, 250 g large titanium hex nuts, 75 g pumice granules, and 275 mL water. Titanium is dense, yes, but just 4.5 g/mL, so about half the density of steel (8 g/mL). The sodalite comes out looking nice. Maybe your low-hardness rocks could likewise benefit from a titanium tumble. Cheers!
@@AncientNovelist I rarely tumble rocks as soft as 3 or 4. Those are typically too soft to tumble. My methods work really well for the rocks I tumble, so I'm not very interested in trying other techniques. I have never heard of anyone using titanium for tumbling rocks, but I'll look into it in case I'm missing something.
I think there are several different materials used for that, from what I've read. Most of them seem too soft to use as a grit. The exception would be aluminum oxide, but that's better used in the later stages of tumbling. But it should work fairly well in the first stage too.
I would like to get a rock tumbler! Where is the best place to get one I’m in Buna TX. Does the price mean anything about how good the tumbler is ? What about the brand of tumbler! I’ve only seen a small one in a Walmart store, it wasn’t very big. Any information would be great, and the time you spend answering is greatly appreciated!
I have my two favorite places to buy tumblers listed in the description of this video. Kingsley North and the Rock Shed are both great businesses. I like Lortone brand tumblers. My first was a Lortone 33B. I think it was a really good choice.
What is the grit recipe for a rebel extreme 17 ? I know you use 1tablespoon of grit for every lb. of rock, but what about stage 2,3,4,5 ? Hoping someone has used this size of barrel and can instruct me on stages and amount. Sure will appreciate it.
¡Buen punto! Eso fue lo primero que pensé mientras Rob explicaba los resultados. Cada cuchara de grit pesa alrededor de 25 g, por lo que 6 T son 150 g. ¡Eso es mucho peso!
¿Te preocupa sobrecargar el vaso? Cuando no estoy realizando experimentos, nunca peso mis vasos. Incluso una vez envié un correo electrónico a un fabricante de vasos para preguntarle si un vaso de tres libras estaba destinado a contener solo tres libras de rocas. Me dijeron que no era necesario pesar los barriles. Siempre y cuando no llenes los barriles con plomo o algo así, ese peso es solo una guía.
Hi @@MichiganRocks Yes, the weight itself is probably immaterial. My concern is relative weight, and my concern may be unfounded. I'm looking at the problem as a chemist, but I have no basis in practice to know whether changes in amount of grit have any bearing on the tumbling process. Grit creates a suspension, and as the fraction of overall composition leans more toward small particles, the behavior of that suspension is going to change. The ability of the suspension to carry objects is going to change. Other behaviors will change. Suspension, dissolution, and interfacial phenomena were at the heart of research I conducted over 35 years. This is not to say I understand what's going on inside the tumbler, because I absolutely don't. But I can think of possibilities that may have bearing due to my experience in studying other systems whose behavior may be based on phenomena common to both tumbling and the purification laboratory. The Lortone 3 lb. barrel has a volume of 760 mL, so just over a pint and a half. A pint's a pound the world around, so that's just a pound and a half, not three pounds. The full weight is obtained because quartz has a density of 2.65 g/mL, and you add rock to 2/3 full, but the rock does not occupy the full 2/3 volume. You can weigh the barrel or do some complicated math to figure out the missing volume, but you already know, since you add a cup (240 mL) of water, and that is enough to almost reach the level of the highest rocks, meaning your rock occupies 2/3 x 760 mL - 240 mL = 266 mL, multiplied by 2.65 g/mL gives 710 grams, which is 1.6 pounds (707 grams/454 grams/pound = 1.557 pound). That's the rock weight. But you also added 240 mL (240 g) water, so you get total weight 2.1 pounds. If you extrapolate to the full volume of the Lortone barrel (that is, if you were to fill the barrel all the way to the top), you'd have a weight of 3.15 pounds. That's where the 3 pounds comes from. Your actual weight will be higher, since grit is unusually dense (about 3.2 g/mL if my calculations are correct), so your 3 tablespoons weigh about 78 grams or nearly a fifth of a pound. Also, some rocks are likely to rise above the 2/3 mark, so now your weight is probably closer to 2.5 pounds (2.1 pounds theoretical weight plus 0.2 pounds grit and another maybe 0.2 pounds of rock). Unless you're using unusually dense rock or metal (as I do; 50 Lincoln pennies, a whopping 9 g/mL, weigh 150 g) and fill over the 3/4 mark, barrel net weight will not exceed 2.9 pounds, so 3 pounds is really the upper limit of fill weight with normal rock. Cheers!
For these, I just read the website that I ordered them from. My geologist son in law explained how the Mohs scale of mineral hardness works and how to do some simple tests in this video: ua-cam.com/video/GpH55EylhX0/v-deo.html
The percentage between the group are not very different. Sure it is the same rock, there might be some slight difference in the chemical make up. Remember hardness was 6.5-7. You could have had some rock at 6.5 in one barrel. The other barrel could have been harder. Need to do some statistic to determine standard deviation and more testing.. just a thought..
I think there were fifty rocks in each barrel, all from the same source. With that many rocks, I would think that any small differences would average out. I do agree that more trials would be necessary for a really definitive answer to my question, but this was enough to satisfy me that three tablespoons is enough.
I was just wondering why you don't just grind and polish everything on your cab machine rather than tumbling them? It seems like it would be much faster.
No, it would be much, much more time consuming for me. With tumbling, I just put them in and check on them once a week. With the cab machine, I have to be standing there doing something to every individual rock. One hard rock could take an hour. I had 50 small rocks in each of the barrels in this experiment. I can't even imagine doing all of those by hand. The other factor is the cost of replacement wheels. The wheels on my cab machine are $80-100 each. They eventually need to be replaced. I can by 45 pounds of grit for just over $100 and that would last over a year if I was just running a couple of barrels. I run more, so I go through it a little faster.
I watched your video on the different grits to buy but I obviously got it wrong lol. I ordered the silicon carbide 80 and 220 but I went off the rails by accidentally ordering the 600 silicon carbide instead of aluminum oxide I am sure you would not consider this a first stage polish but should I still use it or get rid of it? Also I ordered the 1200 aluminum oxide polish from Kingsley north but on their website I can't tell which one to order for a final polish? Any advice would be greatly appreciated 🙏
I'd give the 600 a try, but in the future, I'd go with aluminum oxide at that stage. You could do the 600 silicon carbide, followed by your 1200 aluminum oxide, and then polish. Kingsley North calls it "micro alumina".
grit grinds grit.. if you use too much. your grit becomes finer faster and less effective. basically you stop cutting your rocks and started polishing both your grit and rocks.. i have had similar results with my metal work
I'm curious about this type of thing with the final polishes stage. I've been recently curious of a combo of aluminum oxide and cerium oxide would make any difference. Would like to know if you have tried it and your results :)
Nope, I have pretty much only used aluminum oxide. I also almost always finish my rocks in a vibratory tumbler, so I don't have a lot of experience finishing them in a rotary tumbler.
@@MichiganRocks ahhhhhh. I do not have a vibratory tumbler but I'm hearing I should get one. Your rocks really take such a great polish, from previous videos I was seen. Thank you for your content!!
They are equally smooth. The point of the first stage is not to smooth the rocks, but to grind them down to a good shape. It's the later stages that smooth them out more by removing scratches left by the previous stages.
Thank you for this, I just got started tumbling and I’ve been doing some research w how much grit to use and type and how long, appreciate the experiment 🧪
I'm working on a follow up to this video with more trials. I'm also testing 1 and 2 tablespoons. I'm still running the experiment, so it will be awhile before it's out.
@@MichiganRocks In learning a bit about you over the past many months, I kind of thought you wouldn't be able to just leave it at that. I appreciate your dedication to your craft.
I taught math for thirty years (actually, I'm still teaching it), so I don't get to eat pancakes when I do it. I eat pancakes just because they're delicious.
@@MichiganRocks , i’ve always been horrible at math, couldn’t remember diddley squat. So needless to say, it really caused anxiety when I was in classes for it in college…
@@obieobrien5883 That's a shame. A lot of people think math is about memorizing. Unfortunately that's also how it is often taught. If you understand it, then there isn't nearly as much memorization and everything makes much more sense.
Surprising results that’s for sure ! I’m a 3 tbs man that seems to work well for me and I don’t try and reclaim any grit that might be left over. It seems like a waste of time to me. I’ve had about 4 times in my tumbling career when I’ve opened my first stage barrel and found most of the grit still there and very little removed from the rocks. I assumed that something caused the rocks to lock together as a unit and very little tumbling took place. Awesome video Rob I appreciate you taking these time consuming steps to do these experiments.
I've got a theory. What causes grit to wear down the rocks is friction, which is to say pressure + movement. The tumbling action creates friction as rocks slide past and roll over top each other. (If you overfill the barrel and the rocks cannot move freely, the grit and water splashing around inside the barrel will not grind down the rocks.)
When two rocks are on a collision course -- and there is grit stuck to the rocks -- the friction occurs between the rocks and the grit. The more pressure, the more friction, and the more grinding action. It's like pressing harder with a piece of sandpaper. The amount of grit probably impacts the amount of pressure, and thus the amount of frictional force. If there is too much grit, the tumbling energy will be absorbed by the grit, as the grit is squeezed out from between the rocks without really digging into the surfaces of the rocks. Similarly, the more pieces of grit that are stuck between two rocks, the less pressure there will be as between the surface of the rocks and a specific piece of grit. (It's an issue of pressure decreasing with surface area, like lying on one nail vs. a bed of nails.)
I suspect that the ideal amount of grit is just enough so that there is a very thin layer of grit between the rocks. With a thin layer, the grit will not cushion the tumbling action, and the pressure / friction will not be dispersed excessively over too much surface area.
Too much grit may also result in the grit being broken down primarily by being ground into other pieces of grit vs being scraped against the surface of a rock. You could think of this as the rocks grinding down the grit, as opposed to the grit grinding down the rocks. Grit breaking down grit is counterproductive, which could be why less can be more, as suggested by your experiment.
For anyone who has made it this far, you might as well tell me what you think of my theory. I am not overly attached to it, so feel free to agree, disagree, or improve upon it. Thanks!
That's a better theory than what I came up with and I think it makes a lot of sense. I like your bed of nails example, that really makes it clear to me. I'm also really interested in what others that might have more experience in this area might think. Thanks for taking the time to write that up!
Seams reasonable. There’s just too many variables to be sure what’s going on. Could a more watery slurry suspend the grit and cushion it thus preserving it. Or does it tumble faster breaking the grit even faster? Does the rate at which the slurry thickens affect speed at which the grit breaks down? Does a thicker slurry apply pressure to the grit or clog the sandpaper? Certain rocks can absorb more H2O. Is hard water better for grinding, worse for polishing .Temperature is always a factor. It would clinical trials to be definitive 😂. You guys broke it down pretty good though. Probably better than it should. Fun to think about. He does a good job at taking your mind off things for a while. Happy Holidays
Yep, lots of variables. Hopefully, I did a decent job of eliminating most of them for this very specific experiment.
This was a great example of the scientific process
Generated a bunch of questions and answers✅✅
I've learned something here, a long read😂 but worth it! Thanks guys!
Really pleased to have found you. I’m brand new to rockhounding and your channel has been outstanding in helping me learn about my new hobby, thank you and happy rockhounding 🎉🎉🎉
You're welcome! I'm glad to help out.
Interesting. I know you said you weren't going to do it, but redoing the experiment with 1 and 2 tablespoons of grit might surprise you further. I would also redo the 3 spoon test two more times and look at the mean and variance across 3 samples of the 3 tablespoon test. If the result is highly variable, you have to wonder what factor is causing that to happen.
I thought about doing this for a second week, but weighing all those rocks just takes so long. I figured with four barrels coming out pretty much the same, I had pretty good evidence. I am curious about using a smaller amount though. I don't plan to redo this experiment anytime soon, but maybe some day. I have a couple other experiments planned.
Yes! I agree! I'd love to see this run with less grit...if successful, it could really save some money in the long run. I've been running my first 2 3lb tumblers for 4 weeks now, Saturday is my day to peek inside, rinse and add fresh water and grit. Last time i added 4 Tbs. in like you do, but this time I'll put just 3 based on this outcome! Thanks for doing such great research....and looking forward to more😊
@@MichiganRocks Hey Rob - judging by the numerous requests, your fans are on the edge of their seats on this optimal-number-of-tbsp mystery. I definitely hear ya on the time limitations for experimentation, though - you have to pick and choose and prioritize your time or this could easily turn into a Master's thesis project. But maybe you could reduce the weighing/sorting/matching step by using that "Large Ceramic Media", from Kingsley North or The Rock Shed, as the target "rocks". There are other larger size ceramic tumbling media available from industrial suppliers that might be a better stand-in for target rocks (e.g. a "1" x 1" V-Cylindrical" material from McMaster-Carr). This would reduce the effort to counting the pieces of ceramic media and weighing the the whole batch at once.
This was very good. I follow a few channels. I think MeMiner uses 2 tbsp in his.
@@miltonthecat2240 Ceramic is harder than most rocks I tumble, so that wouldn't really work. I'll consider doing another experiment.
Your attention to detail is very appreciated. Thanks for the instant gratification with the help of your video.
You're welcome, Patricia.
Hello.
I started tumbling in January of this year based on your videos.
However, your device and mine are different, so I created a form that is suitable for my method.
Your video was helpful, thank you.
My device
Rotating tumbler: KT-6808, KT-245 (approximately 3 times the capacity of KT6808)
Vibrating tumbler: SP-B10 (the capacity of KT-245 is just right)
#60/90~#500(+borax) No media used
In KT-6808, there were 3 large spoonfuls of undigested grid, so I used 2 spoonfuls after that.
KT-245 is three times that.
#1000, 3000 : using polishing media
#Polishing :using polishing media, compound and borax
I manage these items using EXCEL, including the equipment used, date, water volume, grid volume, etc.
I'm looking forward to your future videos.
From Japan
It's good to keep records like that. It speeds up the learning process.
Very well planned and executed experiment that's quite relevant to the tumbling community! My guess/theory is that you basically have competition between grit breaking down rock and grit breaking down grit. Above 3 tbsp, the grit breaks down the grit faster than it breaks down the rock. I'd guess that if you did another set of experiments starting at 0.5tbsp and going up to 3, you'd see the rise you expected here, and then the weight loss plateaus like you observed here. I'm not saying you have to do this experiment, but it might help explain what's going on a little better. Great video!
That's an interesting theory. I hadn't really thought of the grit breaking itself down. I should redo this with less grit, but I'm not planning to right now. I have a couple other experiments I want to try first.
Wasn't expecting this as the result either, but great experiment. Your videos are so useful to those of us just starting out.
Thank you Rob! I’ve been tumbling for close to three years now and I am still learning great info from you. Your detailed videos are greatly appreciated.
I've been tumbling for a dozen years and, as you can see, I'm still learning too.
It is really cool that you did this experiment and had the "grit" to report the results to everyone even though it didn't turn out the way you expected.:-)
Gotta love a good pun!
He grindeth slow but exceeding fine!
I love this video.
I love the mathematic set up and rigor. I am impressed by how information rich it is without being dense. I really appreciate how much insight you have given into the hobby of rock tumbling, valuable for spectators and enthusiasts alike.
You really have the rock rizz.
I'm glad you're so happy with my little video! Obviously, I'm learning stuff here too.
New to the hobby.. learning a lot from your videos.. I really appreciate your information, thank you!
You're welcome!
I would love to see more of these types of experiments. I also wonder if more or less water would have played a significant role. I also wonder about the polish stages. 6 tablespoons of polish seems like a lot but I’m following Lortones guidelines.
I have a few more experiments planned. I hope to have the recording of the second part of this one done today. Then there are three others I have in mind.
@@MichiganRocksThat’s great to hear!
Love that you're rocking the Michigan University shirts, too! My boss, Raymond Greene went there to be an Optometrist!! Lol back in like the 80s though. You definitely look younger than him 😂😋
I was there in the late 80's. Graduated in '90.
Very interesting results. Sometimes, we surprise ourselves with trying to understand what works best within our hobbies. Thanks for sharing 👍
I love a good old-fashioned experiment! The rocks are gorgeous.
Michigan Rocks Rocks!! Thanks for all the helpful info from a rock hound and now tumbler in PA
You're welcome!
LOVE how you tried to keep everything the same, down to the weight of the rocks! This channel is a wealth of knowledge! I've wondered myself recently if the amount of water is critical to grinding/polishing efficiency too. I'm very new to polishing rocks, finished one small batch with a nice glossy finish (not perfect but shiny for my 1st attempt). Did the same process with the last batch but they didn't take the shine like the others, the water/cerium oxide slurry mix was not thick at all and guessed that was why. I understand it should be thick almost like a paste. I've got them back on now with slightly less water and gave them another scrub, I've been scrubbing with ivory soap in between stages and keeping things very clean, not to cross contaminate grits.
I plan to test water amount in a future experiment. I can tell you that the slurry definitely does not have to be thick like paste. Most of my slurries are pretty watery but I have a lot of rock dust after I dry out my slurry to dump in the garbage.
I would be very interested to see the results of repeating the experiment with 1 & 2 spoons of grit. I think we were all surprised with those results, maybe we could be in for an even bigger surprise!
I have that video made, but I'm waiting a bit to release it. I have a couple more videos from my southern trip to show first.
Excellent video.
The only explanation I'd have for the barrel, is that the extra grit provided cushioning in the first few days of the tumble.
Really interesting.
I use too much grit.
Hopefully this will save you some money on grit from now on.
@@MichiganRocks sure will, I always follow your guidelines 😊
Thank you for this, I've been using 4 Tablespoons. This will save me some money.
That's what I was hoping to do. Mission accomplished.
Fascinating! Great experiment.
Very interesting if not totally confounding. Thanks for the video.
You're welcome. Even if I don't know exactly what's going on, I'm glad to only use three tablespoons.
Hi, interesting experiment, thank you. I think your explanation is good. Perhaps we also need to consider the distribution of abarasion forces between the grains. The more grains there are between two rocks, the lower the stress on each grain and the lower the abrasion at that point.
Yes, I like that theory. I pinned Jonathan's comment that said the same thing. It's the best theory I've heard.
I was given a Thumler's UV-18 (Industrial) with the appropriate rock approved bowl. I'd LOVE to see a video on tumbling with one of these or similar! I have no idea how much grit to use! I do remember you using a spray bottle to get all the rocks appropriately dampened though.
I don't have a tumbler like that, but I do have a Lot-O vibratory tumbler. You could watch my video on that as a starting point. ua-cam.com/video/hz2E0xJYEWY/v-deo.html
I'd also suggest getting on the Rock Tumbling Hobby forums and asking for some advice there. There will be several people who use that exact tumbler and will be very willing to help you out. You could also just read some old posts and get the information that way. There should be lots of old posts on that very popular tumbler. forum.rocktumblinghobby.com
Love your channel! Would you ever consider making a video about how you created your custom tumbler cabinet? That thing looks fantastic!
I made a couple videos when I first started making videos a few years ago. My friend designed it and asked me not to share the plans, but the videos show it pretty well.
Homemade Tumbler: ua-cam.com/video/6qIcK2ZohGM/v-deo.html
Tumbler Update: ua-cam.com/video/PAMOCc2BNJM/v-deo.html
@@MichiganRocks amazing! Thank you!
New to lapidary and rock tumbling, about 8 months. I enjoy your videos and have learned a lot, thanks. Also thanks for doing this test. I have 2, 6 lb and 1, 12 lb Lortone tumblers. I also have 10 and 18 lb Thumler style vibratory polishers and this week I picked up a used UV-45 tumbler. All of my rock gets the first round in the rotary tumbler. For the 6 lb drums I have used between 3 and 6 Tsp of abrasive with equal results. The 12 lb drum has been 7-10 Tsp abrasive with equal results. Always tumble for a week. Early on I started adding Borax to all stages and I think it helps keep the abrasive in suspension and cutting better. It’s a cheap additive and I’ve always used it. My test on abrasive efficiency is to rinse the slurry after clean out and see how much grit I can detect. A white bucket will tell you how much or little is left after tumbling. All of my polishing after the coarse grit has been in the vibratory polishers. I feel I get a superior finish and I can cut the total polish time to a quarter to a third of the time of doing all stages in a rotary tumbler. Thanks again for sharing your knowledge and experience working and polishing rocks.
I also do almost all of my finishing in a vibratory tumbler. I bought one before my first batch was done, so I have very little experience finishing rocks in a rotary tumbler.
Have you weighed your rocks after tumbling? It sounds like you're just checking to see if your grit has all been used up. When you say you had equal results with twice as much grit, are you just looking at the left over grit, or are you weighing the rocks to see how much was ground away?
Also are your measurements in tablespoons or teaspoons? Tsp is the abbreviation for teaspoons, right? I was measuring in tablespoons.
@@MichiganRocks I stand corrected, I use tablespoons for measuring. I’ve never weighed my rocks throughout the tumbling process. Another UA-camr suggested checking the slurry for grit to see if there was excess after the tumble and that’s my indicator if I’m using enough or too much. I’m not a stickler for perfectly rounded stones, I often prefer the natural way I found it polish. I finish with 2 sizes of ceramic media to get into all of the nooks and crannies. I’ve done some large 3-4 pound Mexican crazy lace agates start to finish in the rotary tumbler with good results. I’m doing palm stone size pieces in the vibratory tumbler with excellent results. I’ve got some 4-5 inch pieces ready for the Thumler UV-45. My goal is to tumble and polish pieces in the 5-10 pound category. I’ve seen others do this with good results. Finding an affordable drum big enough is the challenge for this project.
@@davidsommerfeld2955 I haven't done too many larger tumbles, but I've done a couple. I think large tumbles are awesome though.
I appreciate your thoughts and comments. As always, UA-cam is a wealth of knowledge for beginner rock hounds. The largest single tumble I’ve seen was a stunning piece of Mexican crazy lace agate that weighed 45 pounds if I remember correctly. The guy used a 65 quart tumbler and it took 6 weeks to finish. This gave me motivation to try it on a smaller scale in the 5-10 pound range. Having been a machinist in the past and a brother that has a machine shop, my mind is full of ideas to fabricate equipment to pull this off.
@@davidsommerfeld2955 I don't think it was quite that big, but I think I know exactly what video you're referring to. There's a tennis ball next to the rock in the thumbnail.
Super video! I have always wondered if I should’ve added more grit and now thanks to you, I know! Rob, you’re the best!
Glad to help. I always wondered too.
Great experiment and good results. I have been using 3Tbl and I’m glad to know it’s a good amount. Thank you, I bet it was fun and educational to be a student in your classes!
I think that depends on who you asked. Some kids loved me, others did not. You can't please everyone!
Well done.
👏 Well done experiment. I've been using 2-1/2 tablespoons of 60/90. I think your logic of there is only so much contact area between the rocks so having more grit won't make a difference is valid. If a person goes two weeks instead of one between rinsing, maybe more grit is better. I prefer one week so I can inspect to see if any are ready for stage 2.
I agree with what you said about running them for two weeks. More grit might be better. But like you, I like to get any rocks that are finished out of the tumbler as quickly as I can so they don't get any smaller than necessary.
Yay I love these informational videos.
Thank you for all you do to spread the love of rocks! My family (me, especially I guess) have officially fallen down the rockhounding rabbit hole. Your well-produced videos have inspired many trips to the UP and helped us gear up, better understand, and process our treasures. It is obviously a labor of love, but also a lot of work. Thank you!
Welcome to the rockhounding rabbit hole. Remember to always share the rocks
You're welcome. It is a lot of work, but as you said, I enjoy it.
Great video!
There is no better feeling than being surprised when your hypothesis is completely wrong. I love the scientific method. Everything was really well thought out.
I have to say, though, I would really like to see if 1 or 2 tablespoons would yield similar results. Then the ratio you were looking to diplay would become beneficial. It won't cut down on tumbling time but definatly can prove potential cost savings in grit.
You have great content. I can only imagine how much time and money I saved getting into this hobby by first watching your videos.
I wish I had included two tablespoons in my experiment. Even at the best ratio of grit to amount of material removed, I might still use more grit if more grinding happened. You also have to consider time and electricity. I'd be willing to be a little less efficient with my grit to get faster results.
Great experiment professor Rob. You do the hard work so we don't have to.
Seeing as I have only one tumbler and only one barrel. You saved me at least 5 weeks.
Thanks and I would watch any future experiments you might do.
😀
Yeah, it's easier when you have a bunch of barrels. I'm glad to have saved you a little time!
Great experiment.
This is a great experiment ! I would have thought the same so that was a surprise to me too. I'm still learning doing the research on the products used and what the best ones are. I guess it's personal preference. With you experience in sure you've experimental with many products . I really enjoyed this and enjoy all your videos . Thank you! 😊
I probably haven't experimented with as many as you might think. I did a lot of reading before I started and found good suppliers right away. Since I liked the products I started with, I have just kept using them. There are a few that I have changed, but not many.
Wow, that was not the results i was expecting either.
I think about the time you put in to the details of this by finding the similar weight rocks for each barrel. Not an easy task. Good information to know now when using my small barrels.
Thank you for sharing!
Yeah, that took awhile. I have always wondered about this, so I learned something too.
I like it when you do stuff like this. Another interesting thing to try would be the time to no grit. What about 6 days with 3 tbls ? Is there still grit after 5 days? If it’s gone after 5 days, is there a worthwhile benefit to go the extra 2 days with just the slurry? Or could total tumble time be reduced by a lot by saving that extra time every tumble. Or maybe it just isn’t worth it to try and remember what day to check, as the whole checking every Sunday seems like a good plan to remember.
The grit breaks down over time, so each day there's going to be a little less grinding. You could take them out earlier and replace the grit and get done quicker. Or you could let them go longer and get a little more out of your grit. I think seven days for a tumbler going at the speed of mine is about right. The National Geographic tumbler is much faster and I think for that, four days or so is enough.
More experiments please!!
I have a couple more planned.
Thank you for sharing.
I usually use 1.5 to 2 tbsp. in my 3 lb. barrels and it works just fine.
Another excellent video, thanks for the knowledge
You're welcome, Mike.
As always, great video with helpful information for all of us! I do commend you on these experiments and performing them objectively! 😀
Thanks!
I really appreciated that video. It was very informative and well presented. Thank you for sharing your experiences and knowledge. I love to learn.
Thanks, I'm glad you found it interesting too!
Thanks rob
You're welcome, Gary.
You make amazing and informative videos. I love the beautiful rocks you find and the tutorials on cutting, making jewelry and your experiments! I was just wondering today if the manufacturer recommended grit is really necessary. Think I will give 3 TBS a try. I am very interested in your cabinet full of tumblers. Did you make it yourself? Do the motors running the tumblers get hot? I run a small fan near my tumbler motors to keep them cooler. Have you made a video showing how you set up the tumbling mechanisms? Would love to see more! Thanks again for your awesome videos.
That big tumbler was designed by a friend of mine and I built it. The motor does get hot, which is why it's on top rather than inside the cabinet. That has been running pretty much nonstop for several years with no motor problems.
Here are a couple more videos showing the tumbler in more detail:
Homemade Tumbler: ua-cam.com/video/6qIcK2ZohGM/v-deo.html
Tumbler Update: ua-cam.com/video/PAMOCc2BNJM/v-deo.html
Thank you for the information and links. We will explore this, nice set up and pretty quiet. I have 2 Loretone 33b and they are surprisingly quiet, but I love your set up!
Great experiment! Thanks
Great experiment. I think what you ran into is a viscosity problem. You used excellent experimental design, holding all factors constant, but the viscosity of the water and grit solution probably changed significantly. Viscosity increased as you increased the concentration of grit. A more viscous solution will grind rocks slower because the velocity of the solution moving in the drum decreases because of the increase in viscosity. The friction thing is also pertinent in as much that as you increased the concentration of grit, there was significantly more friction (more viscosity created) between the grains of grit in the solution, again slowing the velocity of the tumbling solution in the drum. There was no detectable difference in the amount of grit present at the end because the grit ground itself as well as the rocks. Just a thought.
Thanks for your theories. I never really thought about grit grinding against itself until you and others pointed that out as a possibility.
I'm not sure about your viscosity theory, though. There are people who add various things to their barrels specifically to create a thicker slurry. The most common things I've heard of are old slurry and clay, sometimes in the form of kitty litter. There is also a product called "Old Miser" that is a slurry thickener. The idea behind thickening the slurry is to make the grit stick to the rocks better. The grit can only work if it's between two rocks, not if it's setting on the bottom of the barrel.
By the way, thanks for this experiment!
You're welcome!
Thank you, Rob! This was extremely helpful!
You're welcome!
Good to know 🤯
I questioned starting at the accepted quantity and not being above and below that amount.
Yeah, I should have tried two tablespoons too. I just never dreamt that more grit wouldn't grind more at least to a point.
I’ve always used 3 in my 3 lb. Who knew it would be optimal. Thanks for confirming. Could it be like a balloon won’t pop if pressed against many nails spaced closely. Push it against one nail and it will. Maybe the grit is doing the same thing to the stones? Too much grit to get a good grind? Crazy results I agree.
My friend Jonathan had the same theory. I let him watch the video early and asked him to put his thoughts in a comment. I pinned it to the top. I think you both have the right idea.
Thanks Rob. I act
Actually only use 1 tablespoon and run for 2 weeks. I used to use 3 but always have grit left over so for me it works best
That's interesting. I almost never have grit left over. The exception is if I put too many really small rocks in the barrel. That almost always results in left over grit.
Only difference I can see is I use Thumler's barrels. Even on my larger barrels (12 and 15 Lb) it is 1 teaspoon per pound. I keep wanting to purchase a Lortone Machine just to see if the barrels make a difference lol@@MichiganRocks
@@11stefanj I have a small Thumler's tumbler and I didn't notice a difference in the way the barrels work. I just notice that the lids wear out really quickly on those little Thumler's tumblers.
Yes they do. I repair them with plexi and the repairs last years! I am going to have to revisit my grit amounts now. You really got me thinking here. @@MichiganRocks
Perhaps a timed viscosity test on remaining slurry might give way to a clue.
I don't know what a timed viscosity test is. I can tell you that the slurries all looked pretty much identical. I guess that's not surprising since they should all have about the same amount of rock dust in them. The only difference would be the amount of grit in the slurry.
great video! Im wondering if you are planning on testing out any of the new Highland Park tumblers. Im curious how they preform.
No, I don't have any plans to do that. They do look interesting though.
Great video! I have been having a hard time getting my rocks done for the later stages of tumbling. I have found myself that 4 tablespoons of 36/70 in a 3 pound barrel is too much even after one week. I want to ask a question though. Will you ever do a review of the Minisonic 4 pound vibratory tumbler? Please do a review if possible. I have had a rough time trying to get a hold of the Lot-o. I love your videos so much they have helped me come a long way. I went from using a National Geographic tumbler with horrible results, to a batch of rocks with an amazing polish and having 18 pounds of tumbling power! I hope you have a great day!
I wanted to do a review of that exact tumbler last winter. I wrote the company and asked them to give me one to review, but they never answered me. I have plenty of tumblers, so I'm not really interested in buying a fairly expensive tumbler that I don't need.
Now, that you have figured out the volume of the rocks lost in the initial course grit, it would have been nice to see if there were any issues with quality. I know you ran them once prior to starting this experiment, however, seeing them up close to see if there was a quality different would have been nice. To me, it is all about quality of the tumbled stone when it is done with the cycle, not about how much I can get done per cycle.
This is only the first stage, so the whole point is to grind as much rock as possible. It's the later stages where the quality matters. I did look at all the rocks to decide which ones that were done with the first stage. I didn't notice any difference in the quality at all.
@MichiganRocks - can you do a similar video but with different water amounts?
It's on my list of experiments. I'm not sure when I'll get to it though.
My daughter bought a Tumblr for me, and I have been obsessed with looking for a stones at the beaches. I live in Southwest Michigan near pier Cove which is a nice beach to go to, but I wanted to know where I can find Agget and how to find them. I’m not having a lot of luck with the rocks. I’m picking up to tumble maybe I’m doing something wrong, but I have been watching all of your videos.
Lake Superior is the best place to find agates, but even there, they are very rare. When I do find one, it's usually tiny. People do find them occasionally in Lake Michigan too. There are a lot of other rocks besides agates that tumble well.
Love the experiment with the amount of grit. What if you used less?
I haven't tried that, so I don't know.
you can catch unused 60/90 grit in a filter. I use nut milk bags (amzn) for cleanouts and it's interesting when I see unused grit.
Do you do that to reuse the grit or just to see if there's any left over?
@@MichiganRocks I use the bags just cuz it's easier to clean a mesh bag of rocks in a bucket of clean water than to rinse a colander. But if I saw I had 3 tbsp of grit leftover I'd maybe try to reuse it.
I was very interested in your results. I'm thinking of replicating your method. I'll report my results in the spring as my tumblers are in the unheated barn in northern Ohio.
More data is always good!
I'm new to rock tumbling. What tumbler would you suggest for me? I have been watching your videos and I am learning alot. Thank you for any and all info.
I like the Lortone 33B. It was my first tumbler. Check the description of this video for The Rock Shed and Kingsley North. They are my two favorite places to buy from.
I was wondering about the polishing stage. Does more polish powder mean the rocks will take a better shine?
No, I don't think that's how it works. I'd go with three tablespoons and let it run for two weeks. More time will polish much better than more polish.
Thanks to you, I know more about rock tumbling than someone should who does not own a tumbler. I was leaning toward the Lortone 33b but can not find them in stock. Is there other tumblers you would suggest? Or should I hold out?
I'd wait for a Lortone. I think Kingsley North and the Rock Shed both have a way to leave your information when they're out of stock. If one of them doesn't, you could always send an email.
I noticed more of mine would move along when putting in 2 tablespoons rather than 3.
I have never used only two tablespoons, but after this experiment, I'm curious.
Hi Rob! My husband bought me an Extreme Rebel 17 which is a 17 pound rotary tumbler. I’m wondering what your grit suggestion would be? Should I stick with 1 tbsp per pound and is that the same for all 4 stages? I’m currently using the Lortone 33B and Lot-O vibratory to finish but my hope is to tumble larger sized rocks requiring the larger barrel for the whole process. Thanks so much for the help and all of your videos!
That's what I would do, but I don't know what's best for that machine. As I said in this video, what I tested was pretty specific and won't necessarily apply to other rocks or other tumblers. I don't have tons of experience finishing rocks in rotary tumblers, so I might not be the best guy to ask. I'd suggest posting your question on the Rock Tumbling Hobby forums.
GO BLUE!!!!!.....😉👍
Hail!
Great experiment! I'm wondering if more grit creates a higher shock absorbing slurry - so some of the energy that would be focused on rock-wearing is perhaps lost to the higher liquid viscosity (reducing tumbling impacts)? Would be interesting to go 3 tablespoons of grit and 3 tablespoons of Borax, and see if that roughly mimics the 6 teaspoon of grit results.
That's a possibility, but the slurries appeared to be the same. Since about the same amount of rocks was ground away in each barrel, I'd expect the slurries to be about the same too.
. . . thank you for.reading my concern. . . can i. use a cement mixer to tumble rocks assorted size using water, grit.is.imported in belize and.would be too.expensive to buy local. . . hope you reach back to me. . .
Rotary tock tumbler barrels are sealed up so that the water doesn't evaporate. I think it would be challenging to keep the rocks wet in a cement mixer. I also tumble them for weeks or months, nonstop. How much would it cost to run a cement mixer for that long?
Thank you for a very informative video. I have a question I’m hoping you can answer. I have just ordered a 17lb tumbler. Do I use 17 tablespoons?
That's what I would do, but I haven't tested it.
Rob, Terrific experimental design and execution. Many questions came to mind during and after your presentation. Are seven days optimal? If it's true that no grit remained in any barrel after 7 days, it seems likely most or all grit would have been gone before 7 days. I tumble coins in rock and grit or titanium and grit, and I am most interested in tumbling effects on coins, so both my methods and objectives are different than yours. But I've found in a couple of experiments that weight loss, in both rock and coin, follows a power curve trajectory over time, so the most rock and coin are removed the first day, less the second day, little on the fifth day, and practically nothing on the 7th day. So I've shortened 1st step tumble to four days--but again, I'm most interested in wear on coins, not on rocks, and my entire methodology is different. Nevertheless, it seems like a study of tumble time might be useful. One of the things I thought of a few weeks ago was maybe starting with two Tsp grit on day one and adding a third Tsp on day four. Some will ask why not just end the tumble at four days. Well, I'm not convinced that presence of grit is the only factor affecting tumble efficiency, and that brings me to the second question. Does grit have an effect beyond interstitial grinding? In particular, I'm wondering if grit affects the aqueous medium, perhaps by changing surface tension, buoyancy, penetrating capability, and so on. Perhaps your seven days is closer to optimal for rocks not because any grit is present but because you're accomplishing other things in the last four to seven days for rocks that I don't see occurring with my coins. I've discovered some interesting things in the last three months. Titanium and sodalite is an excellent combo for copper and bronze pennies (hardness 3), which makes me wonder if such a combo could be more generally applied to hardness 3-4 rocks. Neither titanium nor sodalite loses much weight in the tumble, but the pennies see substantial weight loss. Over maybe 40 days of tumbling the large titanium hex nuts have lost less than 2 percent of start weight and the sodalite is at around 10 percent. I've looked at three densities of plastic beads (0.9, 1.2, and 1.8 grams per mL) and also compared polypro beads vs. HDPE chips. The plastic chips have given me interesting results and I am pursuing more expts. using the little plates (roughly 8 mm square). Coin wear is a complicated process due to the many factors involved (coin weight and composition, strike depth, cultural factors (there are differences in wear between U.S., Canada, and the U.K., possibly due to the way coins are stored, transported, exchanged, etc.), and so on. The work continues. Thanks for the terrific presentation!
I bought a National Geographic tumbler to do a review of because it's such a popular tumbler. One thing that's much different than my other tumblers is that it's very, very fast. I think it's too fast and has potential to damage the rocks, but it also grinds the rocks much faster. With that tumbler, I think four days is plenty.
One of the biggest reasons I run my tumblers for a week at a time is so that I can do clean outs on the same day every week. My neighbor has a couple barrels running at my house and we both know that Sunday is tumbling day. There's nothing to keep track of on the calendar.
Hi @@MichiganRocks Yours seems like the best system for efficiency. I'm sure you could take the time to determine optimal tumble time based on rotation rate, rock type, grit type and weight, and so on, but that in itself would take time, and then scheduling for 5.5 days for barrel A, 3.7 days for barrel B, and 9 days for barrel C would become a logistical nightmare. You'd be setting your alarm to go off at 2:00 in the morning, change the barrel, go back to bed for 2 hours, change the next barrel, and so on. What a mess that would be! But others might benefit from knowing, for example, that 4 days of tumbling achieves, let's say, gives 82 percent of weight loss relative to 7 days in the tumbler. While my data indicate something like this may be true, it may nevertheless be better for the rocks to tumble that extra 3 or 4 day. Your objective is not weight loss, after all, but polishing the rocks. My suspicion is that polishing is essentially going on in parallel with coarse abrasion, and probably following a different timeline than coarse abrasion, so that shortening the run time brings you to a place where the rocks just aren't ready for Step 2, even if they otherwise meet your criteria for moving on. But I could be wrong. Maybe shorter run time will work for many rocks. It certainly works for coins, at least for the experiments I'm performing. I'm just going to come out and recommend you give titanium a try for your hardness 3-4 rocks. I am finding good metal removal on my copper/bronze coins, but coin wear after tumbling in titanium is less severe and more natural than I find after tumbling in standard quartz and silicon carbide grit. Something similar could happen if you try titanium on rock: good coarse removal but better polished stones after Step 1. To wear 100 g of pennies I typically use 300 g sodalite, 250 g large titanium hex nuts, 75 g pumice granules, and 275 mL water. Titanium is dense, yes, but just 4.5 g/mL, so about half the density of steel (8 g/mL). The sodalite comes out looking nice. Maybe your low-hardness rocks could likewise benefit from a titanium tumble. Cheers!
@@AncientNovelist I rarely tumble rocks as soft as 3 or 4. Those are typically too soft to tumble. My methods work really well for the rocks I tumble, so I'm not very interested in trying other techniques. I have never heard of anyone using titanium for tumbling rocks, but I'll look into it in case I'm missing something.
where do you get your grits? Kingsley? Interesting results
Kingsley North and the Rock Shed.
Ahhh yes...rock shed great too
What is your opinion using sandblasting grit
I think there are several different materials used for that, from what I've read. Most of them seem too soft to use as a grit. The exception would be aluminum oxide, but that's better used in the later stages of tumbling. But it should work fairly well in the first stage too.
I would like to get a rock tumbler! Where is the best place to get one I’m in Buna TX. Does the price mean anything about how good the tumbler is ? What about the brand of tumbler! I’ve only seen a small one in a Walmart store, it wasn’t very big. Any information would be great, and the time you spend answering is greatly appreciated!
I have my two favorite places to buy tumblers listed in the description of this video. Kingsley North and the Rock Shed are both great businesses. I like Lortone brand tumblers. My first was a Lortone 33B. I think it was a really good choice.
What is the grit recipe for a rebel extreme 17 ? I know you use 1tablespoon of grit for every lb. of rock, but what about stage 2,3,4,5 ? Hoping someone has used this size of barrel and can instruct me on stages and amount. Sure will appreciate it.
I'm not sure. I do most of my later stages in a vibratory tumbler. I'd just start doing some experimenting if I was you.
Hello
Hola Rob. Pienso que al poner mayor cantidad de silicio, deberia poner menos rocas para compensar la carga. Saludos cordiales desde Argentina!
¡Buen punto! Eso fue lo primero que pensé mientras Rob explicaba los resultados. Cada cuchara de grit pesa alrededor de 25 g, por lo que 6 T son 150 g. ¡Eso es mucho peso!
¿Te preocupa sobrecargar el vaso? Cuando no estoy realizando experimentos, nunca peso mis vasos. Incluso una vez envié un correo electrónico a un fabricante de vasos para preguntarle si un vaso de tres libras estaba destinado a contener solo tres libras de rocas. Me dijeron que no era necesario pesar los barriles. Siempre y cuando no llenes los barriles con plomo o algo así, ese peso es solo una guía.
Hi @@MichiganRocks Yes, the weight itself is probably immaterial. My concern is relative weight, and my concern may be unfounded. I'm looking at the problem as a chemist, but I have no basis in practice to know whether changes in amount of grit have any bearing on the tumbling process. Grit creates a suspension, and as the fraction of overall composition leans more toward small particles, the behavior of that suspension is going to change. The ability of the suspension to carry objects is going to change. Other behaviors will change. Suspension, dissolution, and interfacial phenomena were at the heart of research I conducted over 35 years. This is not to say I understand what's going on inside the tumbler, because I absolutely don't. But I can think of possibilities that may have bearing due to my experience in studying other systems whose behavior may be based on phenomena common to both tumbling and the purification laboratory. The Lortone 3 lb. barrel has a volume of 760 mL, so just over a pint and a half. A pint's a pound the world around, so that's just a pound and a half, not three pounds. The full weight is obtained because quartz has a density of 2.65 g/mL, and you add rock to 2/3 full, but the rock does not occupy the full 2/3 volume. You can weigh the barrel or do some complicated math to figure out the missing volume, but you already know, since you add a cup (240 mL) of water, and that is enough to almost reach the level of the highest rocks, meaning your rock occupies 2/3 x 760 mL - 240 mL = 266 mL, multiplied by 2.65 g/mL gives 710 grams, which is 1.6 pounds (707 grams/454 grams/pound = 1.557 pound). That's the rock weight. But you also added 240 mL (240 g) water, so you get total weight 2.1 pounds. If you extrapolate to the full volume of the Lortone barrel (that is, if you were to fill the barrel all the way to the top), you'd have a weight of 3.15 pounds. That's where the 3 pounds comes from. Your actual weight will be higher, since grit is unusually dense (about 3.2 g/mL if my calculations are correct), so your 3 tablespoons weigh about 78 grams or nearly a fifth of a pound. Also, some rocks are likely to rise above the 2/3 mark, so now your weight is probably closer to 2.5 pounds (2.1 pounds theoretical weight plus 0.2 pounds grit and another maybe 0.2 pounds of rock). Unless you're using unusually dense rock or metal (as I do; 50 Lincoln pennies, a whopping 9 g/mL, weigh 150 g) and fill over the 3/4 mark, barrel net weight will not exceed 2.9 pounds, so 3 pounds is really the upper limit of fill weight with normal rock. Cheers!
@@AncientNovelist Well that's something that I never calculated. It's nice to see where that number actually comes from. Thanks for sending that!
How do you determine the hardness?
For these, I just read the website that I ordered them from. My geologist son in law explained how the Mohs scale of mineral hardness works and how to do some simple tests in this video: ua-cam.com/video/GpH55EylhX0/v-deo.html
The percentage between the group are not very different. Sure it is the same rock, there might be some slight difference in the chemical make up. Remember hardness was 6.5-7. You could have had some rock at 6.5 in one barrel. The other barrel could have been harder. Need to do some statistic to determine standard deviation and more testing.. just a thought..
I think there were fifty rocks in each barrel, all from the same source. With that many rocks, I would think that any small differences would average out. I do agree that more trials would be necessary for a really definitive answer to my question, but this was enough to satisfy me that three tablespoons is enough.
👁👁 Always a pleasure thanks for this information…🎄❤️ 🕎
9:37
I was just wondering why you don't just grind and polish everything on your cab machine rather than tumbling them? It seems like it would be much faster.
No, it would be much, much more time consuming for me. With tumbling, I just put them in and check on them once a week. With the cab machine, I have to be standing there doing something to every individual rock. One hard rock could take an hour. I had 50 small rocks in each of the barrels in this experiment. I can't even imagine doing all of those by hand.
The other factor is the cost of replacement wheels. The wheels on my cab machine are $80-100 each. They eventually need to be replaced. I can by 45 pounds of grit for just over $100 and that would last over a year if I was just running a couple of barrels. I run more, so I go through it a little faster.
@@MichiganRocks thx for the getting back to me it makes total sense.
I watched your video on the different grits to buy but I obviously got it wrong lol. I ordered the silicon carbide 80 and 220 but I went off the rails by accidentally ordering the 600 silicon carbide instead of aluminum oxide I am sure you would not consider this a first stage polish but should I still use it or get rid of it? Also I ordered the 1200 aluminum oxide polish from Kingsley north but on their website I can't tell which one to order for a final polish? Any advice would be greatly appreciated 🙏
I'd give the 600 a try, but in the future, I'd go with aluminum oxide at that stage. You could do the 600 silicon carbide, followed by your 1200 aluminum oxide, and then polish. Kingsley North calls it "micro alumina".
Thanks I really appreciate the name of the polish
grit grinds grit.. if you use too much. your grit becomes finer faster and less effective. basically you stop cutting your rocks and started polishing both your grit and rocks.. i have had similar results with my metal work
Someone else said the same thing and it makes sense. Thanks for sharing your experienced observation.
You should have tried 1 tbs and 2
Yes, I realize that now. I didn't then.
I'm curious about this type of thing with the final polishes stage.
I've been recently curious of a combo of aluminum oxide and cerium oxide would make any difference. Would like to know if you have tried it and your results :)
Nope, I have pretty much only used aluminum oxide. I also almost always finish my rocks in a vibratory tumbler, so I don't have a lot of experience finishing them in a rotary tumbler.
@@MichiganRocks ahhhhhh. I do not have a vibratory tumbler but I'm hearing I should get one. Your rocks really take such a great polish, from previous videos I was seen. Thank you for your content!!
Which are the smoothest?
They are equally smooth. The point of the first stage is not to smooth the rocks, but to grind them down to a good shape. It's the later stages that smooth them out more by removing scratches left by the previous stages.
@@MichiganRocks Ok. Was thinking relative to how they began.
The harder your grit in first stage process then grade as you go,,Aluminum Oxide will get the harder rocks in ship shape.
Silicon carbide is a better grit for the first stage. I did an experiment on that too. ua-cam.com/video/hcRttq9bSrY/v-deo.html
Now try it with two and one tbsp
For right now, I'm happy with using three. Maybe some day.
Perhaps, the excess grit grinds on itself?
Several people have suggested that as a possibility. I think it's a good theory.
Thank you for this, I just got started tumbling and I’ve been doing some research w how much grit to use and type and how long, appreciate the experiment 🧪
You're welcome. I have started another video with an experiment on 1, 2, 3 and 4 tablespoons.
Hmmm.... IDK 🤷♀️
I'm working on a follow up to this video with more trials. I'm also testing 1 and 2 tablespoons. I'm still running the experiment, so it will be awhile before it's out.
@@MichiganRocks In learning a bit about you over the past many months, I kind of thought you wouldn't be able to just leave it at that. I appreciate your dedication to your craft.
Next experiment 2 and 1 tablespoon's!.
I don't plan to do that. I'm happy using three.
😍😍😍
I wish you would have ran a fifth barrel with NO grit.
I did that when I experimented with using sand for grit. The results were pretty surprising. ua-cam.com/video/rk1DEqyH8Pc/v-deo.html
If you don’t do any future videos then we’ll know the grit industry has threatened to harm you or label you as misinformation.
Ha ha! I hope not!
For me, anything math equals anxiety-ridden pancakes.
I taught math for thirty years (actually, I'm still teaching it), so I don't get to eat pancakes when I do it. I eat pancakes just because they're delicious.
@@MichiganRocks , i’ve always been horrible at math, couldn’t remember diddley squat. So needless to say, it really caused anxiety when I was in classes for it in college…
@@obieobrien5883 That's a shame. A lot of people think math is about memorizing. Unfortunately that's also how it is often taught. If you understand it, then there isn't nearly as much memorization and everything makes much more sense.
I'm curious what happens if you use less? Awesome experiment, Rob!! ROCK ON!! 😁👍🏻🪨⛏️
No idea, I haven't tried that.
Surprising results that’s for sure ! I’m a 3 tbs man that seems to work well for me and I don’t try and reclaim any grit that might be left over. It seems like a waste of time to me. I’ve had about 4 times in my tumbling career when I’ve opened my first stage barrel and found most of the grit still there and very little removed from the rocks. I assumed that something caused the rocks to lock together as a unit and very little tumbling took place. Awesome video Rob I appreciate you taking these time consuming steps to do these experiments.
@@davidhile5363 I rarely have grit left over either. Only happens when I tumble too many small rocks.