osuguy0301
starting to spend too much on rocks
Member since December 2015
Posts: 203
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Post by osuguy0301 on Dec 28, 2016 10:49:57 GMT -5
For those of you who shape in a rotary and finish in a Loto, what grit are you using in your rotary? Currently I got about 5 lbs left of 60/90 and am using that. Should i be going to a more coarse grit so they will shape more quickly?
I just started running my QT66 today and have realized that the 5lb bag I have isn't going to last long. Any suggestions on a place to get bulk grit (50lbs+) for a good price?
Thanks, Jake
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Post by captbob on Dec 28, 2016 11:07:08 GMT -5
I'm sure I will be just one of many to chime in here... I used 60/90 as my coarse grit for YEARS. It works just fine, although coarser grits may shape faster. How big of a hurry are you in? In the past 6 months, or so, I have started using 30 and 46/70 grits for my (starter) coarse grit. MY findings in the short time that I have been using these coarser grits is that they do seem to do the job faster. BUT, I am finding that I am having trouble having the 30 grit break down all the way in my rubber liner barrels. That does not mean that it is not doing it's job, but I'm wondering if it's just too coarse of a grit for a rubber barrel. Logic says that the coarse grits would wear the barrel and lid gasket faster, Do Lortone barrels have a rubber lid gasket like Thumler's 15lb barrels? Anyway, personally, I would suggest going with the 46/70 grit if you want to speed things up. As I said, the 60/90 has always done the job for me, may just take a bit longer - I'm in no hurry. Best prices I've found for bulk grits are at Kingsley North. 50 lbs shipped in a Flat Rate box. Checking out will not show the FR shipping price. If you buy there, don't worry about the price shown at checkout, they will adjust it. grit page(s) www.kingsleynorth.com/skshop/category.php?catID=105346/70 - 50 lbs = $88 + around 18 bucks FR shipping www.kingsleynorth.com/skshop/product.php?id=97572&catID=1053
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ChicagoDave
has rocks in the head
Member since June 2016
Posts: 720
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Post by ChicagoDave on Dec 28, 2016 11:32:04 GMT -5
I use 46/70 and just purchased 50lbs from Kingsley North. Not sure if it's any better than 60/90, but it appears fully broken down when I get around to cleaning out the barrels (every 5-7 days).
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Post by captbob on Dec 28, 2016 11:44:34 GMT -5
I use 46/70 ... Not sure if it's any better than 60/90, Bingo. Again, "logic" says it would do the job faster, but it's not going to be a day & night difference. Maybe not even noticeable in the long run. Both will do the job. My recommendation, if you are wanting to buy just one coarse grit in bulk, would be 46/70 OR 60/90 - not the 30 grit.
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richardh
spending too much on rocks
Member since June 2016
Posts: 391
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Post by richardh on Dec 28, 2016 12:12:30 GMT -5
I have been doing this less than a year so far so I'm definitely not the most experienced here but so far what I have found is that 60-90 works well. I never had trouble with it breaking down without the use of clay.
More recently I started using 30 grit and using the same methodology I was using with the 60-90 I was having a LOT of trouble getting it to break down.
With the 30 grit I have to use considerable amounts of clay to get it to break down. I find that I get good results with a 1:1 grit:clay ratio by volume.
With the coarser grit the grit will just sit on the bottom of the barrel where it can't do much grinding. The clay suspends the grit and spreads it over all surfaces of the rocks where it can do its job efficiently.
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Post by Garage Rocker on Dec 28, 2016 12:14:19 GMT -5
I've had the same results Bob mentioned above, the 46/70 works great in the QT66. The 30 didn't work for me either. Or rather, it didn't seem to want to break down all the way. Still don't know if it's the rubber barrel, which I suspect plays some part, or that I never got the slurry right to carry the grit, which is possible too. It was more trouble to try to fix that problem than it was to just trade off the 30 grit and go back to using the 46/70. I do throw a palm full of kitty litter in there with the 46/70 to thicken the slurry a little. And yes, get the bulk grit from Kingsley.
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Post by HankRocks on Dec 28, 2016 12:18:40 GMT -5
Been thinking of changing from 80 to something coarser myself. Maybe 60, or 46/70. It does make sense that the coarser grit will wear the rubber quicker, especially the lid liner on the Thumler. Of course it should reduce the time of the run in the coarse grit so that reduces the wear on the Lid. Not sure where the two curves cross, I am getting a headache thinking about it!!
H
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Post by captbob on Dec 28, 2016 12:55:13 GMT -5
Couple things here... Hank, I wouldn't be buying 80 grit. Nothing wrong with it, just that single graded grits are usually more expensive than multi-grit mixes. Same with 220 grit. It's a good grit, but more expensive than the 120/220 mix. Go with mixes on these coarser grits unless you have a specific need for a single graded grit. With the coarser grit the grit will just sit on the bottom of the barrel where it can't do much grinding. The clay suspends the grit and spreads it over all surfaces of the rocks where it can do its job efficiently. *sigh* (because of the typing) Grit can not "sit on the bottom". Well, maybe it can, but I'll get to that later. What I reckon you are experiencing is seeing the grit with rocks in it stuck to the bottom of a barrel when you do clean outs or check on your rocks. This grit on the bottom was not there when the barrel was running (one exception). This bottom muck (for lack of a better word) happened when you took the barrel off the tumbler rollers and set it upright to open it. Just as a bucket of mud will settle and the clay/dirt goes to the bottom with the finer silt and water on top of it. Same thing when you clean the oil out of a big rock saw. Same with ANY mixture with a liquid and solids in it, providing the solid in the mix is heavier than the liquid. Yeah, I know it looks like there is a mass of grit and rocks stuck to the bottom of the barrel when you check it, but that just happened. It happens in a quickness once the barrel rotation ceases. Try removing a barrel next time you do a clean out and set the barrel on it's side (never hold it upright and keep the same side up), get it outside or over a wash pan (cat litter box works well) and open the barrel. It's gonna be messy, but you can clean up easily enough. You will find the grit/rock muck stuck to the bottom/lowest "side" of the barrel and not to the bottom as you usually find it. It will also be stuck (settled) against the lid and bottom as well, but all at the same level. That's just what grit does. It settles when not in motion. The one possible exception that I can think of (maybe others that wiser folks can come up with?) for grit being stuck on the bottom would be if during a check on your rocks -not a total clean out- the grit muck may settle and you get the bottom stuckage (new word!). Even then, I would think that it would become unstuck and remix into the rest of the slurry once you get things rolling again. Hope this makes sense. Might discuss loading a barrel if/when I can make the time and I remember. It's not rocket science, but common sense comes into play. ETA: richardh what size barrels are you using with 30 grit? < font = curious >
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Post by captbob on Dec 28, 2016 13:27:22 GMT -5
OR...Are you saying that you think that 30 grit in a freshly loaded barrel stays at the bottom of a rotating barrel and does not mix (rotate) with the rock load? I may have misunderstood what you meant by "the grit will just sit on the bottom". If you are just saying that the very coarse 30 grit does not mix well when rotating, then yes -absolutely- it makes sense that a good slurry will help pick it up, and clay/cat litter seems to be an easy way to speed up slurry creation. I've been doing this stupid tumbling stuff for awhile and have never needed additives to create a slurry until I tried these grits coarser than 60/90. My call is still out on the degree of advantage with enhanced slurry. Time will tell. jamesp has done extensive experimentation with such (instant slurry creation) and seems to be having very beneficial results. (aww gee - hope mentioning his slurry wizardry doesn't cause anyone here undue consternation!)
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Post by HankRocks on Dec 28, 2016 13:58:58 GMT -5
Just looked in the Kingsley catalog, the price for 30, 60, 80, 100, 36/100, 46,70, 60/90 are all the same. I would have thought there would have been a difference. It does start to get cheaper when you get to the 120/220 vs 220.
Hank
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Post by captbob on Dec 28, 2016 14:47:36 GMT -5
yeppers, Kingsley North is the place to buy grit! Not everyone knows of the place though. Many sites (the Rock Shed & others) selling grit tend to charge more for single graded grits. Thinkin' that Kingsley North must get their popular grit sizes in by the train car full. Wonder where they buy from. Probably have to buy in their quantities to get those low prices.
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Post by Garage Rocker on Dec 28, 2016 15:19:46 GMT -5
jamesp has done extensive experimentation with such (instant slurry creation) and seems to be having very beneficial results. (aww gee - hope mentioning his slurry wizardry doesn't cause anyone here undue consternation!) Nope, no consternation. I will, however, donate 5 minutes of photoshop time for the viewers' pleasure, because I'm also magnanimous.
CaptbobHaHa
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richardh
spending too much on rocks
Member since June 2016
Posts: 391
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Post by richardh on Dec 28, 2016 15:21:09 GMT -5
With the coarser grit the grit will just sit on the bottom of the barrel where it can't do much grinding. The clay suspends the grit and spreads it over all surfaces of the rocks where it can do its job efficiently. *sigh* (because of the typing) Grit can not "sit on the bottom". Well, maybe it can, but I'll get to that later. Sorry for stimulating you to do so much unwanted and as it turns out unnecessary typing. My statements are based from direct observations of the tumbler in action. After struggling with the SiC 30 for quite some time and continuously reading all these glowing reports about it from JamesP I decided I needed to approach the problem in a bit more of a systematic fashion. First I wanted to try to see what was actually going on in the barrel during tumbling so I decided to try a transparent barrel. It turns out that I was able to use a quart glass jar in order to directly observe what was going on with the grit. I started with my typical loading, which at the time was the barrel (jar in this case) filled 60% full with rough rocks (from ¼” to 2” material) and water up to 1” below the top of the rough rocks. Then I added 3 tbsp of 60-90 grit, sealed it up and started it tumbling. Immediately I could see the water getting quite turbid/opaque and grit spread all over the inside of the jar as well as all over the rocks. Though it was difficult to see exactly what was happening at the bottom of the rock pile I was unable to detect much/any grit buildup on the bottom of the barrel. I then washed everything off and did the exact same load substituting the 60-90 with 30 grit. Once tumbling started there were some obvious differences from the first test. First the water wasn’t turbid at all and second I could see that some of the SiC particles were getting stirred up into the rock pile, the vast majority were just staying settled on the bottom of the rock pile in the tumbler as it rotated. At that moment the reason for the lack of breakdown of SiC 30 I had been struggling with became painfully obvious. If you think about it the problem should have been obvious before these experiments but I guess I am a visual person and I needed to see it with my own eyes before everything sunk in. I had actually made the necessary observations before these experiments but they hadn’t clicked. When I do my cleanouts I always scavenge the unused SiC 30 based on the relationship between settling time vs particle size. The smaller particles of broken down grit take longer to settle than the large particles. So when I stir up the sludge from my failed tumbling runs in plenty of water I can decant away all of the smaller particles and end up with a fairly uniform coarse grit. If I look at the other extreme, when I have tried to recover my polish in the past it often takes many hours or even days for the grit/polish to settle to the bottom of the container. The water that I was using as my transfer medium in my rock tumbling simply didn’t have enough viscosity to keep the larger grit particles suspended though it does apparently have enough viscosity to keep the finer particles of the 60-90 grit suspended enough that they can actually do their job. About the same time that I was coming to my realizations about my viscosity problem JamesP started trumpeting the benefits of his red clay. It made sense that the clay should make the transfer medium viscous enough to get the coarse SiC particles distributed within the barrel. With this in mind I decided to try my SiC 30 experiment again but this time also adding a tablespoon of cat litter. As the cat littler particles broke down I could see that the inside of the jar was getting coated quite quickly and I could see some SiC particles sticking to the walls of the jar that weren’t submerged. Well I figured the problem was solved so I started using that formula in my 3lb rubber HF barrels. Unfortunately I hadn’t quite nailed down the problem as after a week of running I still hadn’t totally broken down all of the SiC 30. It took a few more weeks of messing around but I eventually figured out that I could get all of the SiC 30 to break down in three days if I did a 1:1 Sic 30:cat litter ratio. Anyway I hope some of this information is helpful to someone. I know I am just a beginner but after a lot of struggling this is what is working for me now.
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richardh
spending too much on rocks
Member since June 2016
Posts: 391
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Post by richardh on Dec 28, 2016 15:24:31 GMT -5
OR...Are you saying that you think that 30 grit in a freshly loaded barrel stays at the bottom of a rotating barrel and does not mix (rotate) with the rock load? I may have misunderstood what you meant by "the grit will just sit on the bottom". If you are just saying that the very coarse 30 grit does not mix well when rotating, then yes -absolutely- it makes sense that a good slurry will help pick it up, and clay/cat litter seems to be an easy way to speed up slurry creation. I've been doing this stupid tumbling stuff for awhile and have never needed additives to create a slurry until I tried these grits coarser than 60/90. My call is still out on the degree of advantage with enhanced slurry. Time will tell. jamesp has done extensive experimentation with such (instant slurry creation) and seems to be having very beneficial results. (aww gee - hope mentioning his slurry wizardry doesn't cause anyone here undue consternation!) Yes, as hard as it may be for you to believe, I do have a basic understanding of physics. I may not have been on this planet for very long but I have observed the effects of gravity once or twice.
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Post by captbob on Dec 28, 2016 15:59:27 GMT -5
I love it! Although the Skipper is a bit more rotund than I, it still works. Wife unit will get a kick outta that! Your photoshop work is amusing, not concerned richardh , so my 2nd post was what you were referring to. All good. Nice experimentation with the glass jar barrel to get your visual understanding. Seems to go right along with James' clay tinkering. A slurry is needed to carry these coarsest grits. Wonder how much the roundness/smoothness of the glass jar lessened the ability of the coarser grit to climb the wall and mix with the rocks.
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osuguy0301
starting to spend too much on rocks
Member since December 2015
Posts: 203
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Post by osuguy0301 on Dec 28, 2016 20:03:34 GMT -5
Thanks for all the replies. I will stay away from the 30 grit. I was thinking about getting some but if its more trouble than its worth, I will leave it alone. I have only ever tumbled with 60/90 so I may just stick with that when buying 50lbs because i know I won't have any issues with it. I will probably buy a 5lb quantity of the 46/70 and give it a try.
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richardh
spending too much on rocks
Member since June 2016
Posts: 391
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Post by richardh on Dec 28, 2016 20:47:35 GMT -5
The SiC 30 does definitely take some extra effort, mainly that you pretty much seem to need to use it with a slurry thickener like clay/cat litter. The 46-70 and 60-90 both are pretty hassle free in my experience. Having said that, now that I have gotten the SiC 30 situation figured out I will be ordering more once my current supply runs out.
I have done limited testing on the difference in grinding efficiency between the SiC 30 and SiC 60-90. My data set is very limited but after four runs with the SiC 30 and two with SiC 60-90 it looks like I am getting close to 40% more mass loss per cycle with the SiC 30.
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Post by Jugglerguy on Dec 28, 2016 23:54:52 GMT -5
I'll just chime in and say that I have had similar results as Bob. I used to use 60/90, then I used 80, and now I use 46/70. I haven't noticed a huge difference in any of them, but I'll keep buying 46/70. I buy the coarse stuff from Kingsley North, but I get my other grits from The Rock Shed, especially the polish. I did also buy some OMG2 polish from johnjsgems gems that I used in the World Tumbling Contest, but I usually just use The Rock Shed's aluminum oxide polish. I'll save the OMG2 for special occasions.
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,557
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Post by jamesp on Dec 29, 2016 4:52:38 GMT -5
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,557
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Post by jamesp on Dec 29, 2016 6:12:11 GMT -5
At least consider straight SiC 46. 46/70 is half 70. 70 does not cut much. But the 70 will help you build a slurry. Expensive slurry... Carry on
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