JC
starting to spend too much on rocks
Member since September 2004
Posts: 107
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Post by JC on Jan 6, 2005 13:23:07 GMT -5
Another newby question... I'm running my first two runs. One is Aquamarine rough and the other is some Mook Jasper. I started out with the Aqua and have been trying to shape this stuff up for three weeks now. It is still grinding away but I'm making sloooowwwwww progress. I started out with three 3lb barrels and when I finally ground away enough to liberate one barrel I started up with the Mook. Since I am a beginner I've been keeping good notes and doing more inspecting than is necessary just to give me a good idea of what things should look like. Here is my observation. I've been using only 2.5 tablespoons of 80 grit per barrel. I started out using three but I would end up with wasted grit at the end of the 7 day grind(for the Aqua). Yeah I could let it go longer but I wanted to have a regimen set up. I've cut back to 2.5 and only have a little bit of visible grit at the end of the week. I started the Mook and at the end of the week I observed no grit at all was visible. The second week of the 80 grit grind(the Jasper is definitely faster, almost done) I decided to check mid-week on the barrels. To my surprise the grit has already broke down. My questions are:
1. Does this necessitates a midweek recharge? 2. Should I just dump in more grit or wash the rocks then add more grit? 3. What is causing this noticeable difference in grit breakdown, differences in the rocks hardness between Aqua and Jasper? I’ve tried to keep all other variables the same, water level, rock size, etc. 4. I've made the assumption that if the slurry is smooth and I can't see anymore visible 80 grit in the slurry or on the rocks that the grit has dissipated, correct?
TIA!
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Post by krazydiamond on Jan 6, 2005 13:58:23 GMT -5
good to see you on the board, JC!
your aquamarine is a lot harder than your mook, so it will take longer for harder stones to shape.
the grit does break down, but a good thick slurry is much to be desired. it's still working even if you can't discern grit.
if you aren't happy with your 80 stage, recharge (wash and reload) after 7 days. repeat until you ARE happy with the shape.
if you are still seeing grit at the bottom after 7 days, you may not be charging the barrel properly as 4 tbsp. should all break down in 7-10 days.
hang in there, JC, glad to know you are out there tumbling!
KD
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Post by Cher on Jan 6, 2005 14:22:29 GMT -5
Hi JC, I use 1 tablespoon of 60/90 grit, anytime I use more I end up with lots of grit left over, even though I religiously shake the barrels daily to keep it stirred up. Even after a week straight, there's still grit left. I figure it's just being wasted so that's why I cut down. Good to see you JC ... stay safe, our prayers are with you all over there.
Cher
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Post by connrock on Jan 6, 2005 20:36:15 GMT -5
Hi JC, In a rotary tumbler the grit breakes down 1/2 of it's original size every 7-10 days. So if you start out with #80 it will be #160 in 7-10 days and so on. Just because you cant see it doesn't mean it's not there.It's just a lot finer. Tom
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JKowalski33
spending too much on rocks
Member since August 2004
Posts: 451
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Post by JKowalski33 on Jan 6, 2005 21:02:08 GMT -5
rosebud, how can you only use 1 tablespoon? i have this little cup with a line marked on it that i made, i think its 3 tablespoons if i remember right. but anyways, i use one of those in a 3 lb barrel, and it all gets used up after 7 days..
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HarryB41
has rocks in the head
Member since September 2004
Posts: 605
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Post by HarryB41 on Jan 6, 2005 21:50:23 GMT -5
Hi JC, In a rotary tumbler the grit breakes down 1/2 of it's original size every 7-10 days. So if you start out with #80 it will be #160 in 7-10 days and so on. Just because you cant see it doesn't mean it's not there.It's just a lot finer. Tom I am going to give this a try: A 3lb. load with 60 git and let it just run for 4 weeks and see what happens. I had a guy tell me awhile back that he had a friend that started a load and let it run for 6 months and you could not tell the diff from it and a reg load with polish. I have been wanting to try this and I will as soon as I am moved and comfortable. Harry
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JC
starting to spend too much on rocks
Member since September 2004
Posts: 107
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Post by JC on Jan 6, 2005 23:45:10 GMT -5
Thanks for all the good advice.
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Post by puppie96 on Jan 7, 2005 1:29:40 GMT -5
Here's one more.... I always use Lortone's proportions. Always. They say 4 TBSP of 60/90 to a 3-lb. barrel, they designed the unit, I obey.
Now, about grit breakdown. IF all has gone as planned, at the end of 7 days I've got a fairly thick slurry in which, if you rub it between your fingers you don't feel grittiness, and on the inside of the top cover, you can't see any shiny pieces of grit. At that point it's time to wash out and recharge, either moving to next stage or more 60/90. Sometimes when I open to check it for the first time, a couple days after starting it, I'll find that it seems to be nothing but water and grit. Pouring off some of the water usually helps with this. In a couple more days it will usually have thickened. Sometimes at the end of 7 days, it still seems watery and there is a lot of grit remaining in the bottom. This, I don't believe signifies overuse of grit but that for some reason (probably too much water) it didn't perform right. Again I'd reduce the water. Sometimes I'll add more small stuff such as the fishtank size gravel that gradually accumulates in my washout buckets. That will usually help it slurry-up.
By the way I've read at least one set of tumbling instructions written by somebody who knew what they were talking about, that said that you SHOULD have a bit of unprocessed grit left at the end; that's how you know that you still had it working throughout until you stopped the cycle.
People talk about leaving it in an endless 60/90 cycle because the grit breaks itself down to finer grades as you go along, etc. I've never tried it myself, I recall others mentioning trying it and I thought they felt it was very time consuming. If you do it don't forget to keep checking the water level! They do dry up if they are left a long time.
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rollingstone
starting to spend too much on rocks
Member since July 2009
Posts: 236
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Post by rollingstone on Jan 7, 2005 3:29:37 GMT -5
Okay, I have been puzzling over the grit thing lately, and wasn't going to bother bringing it up, but since you have JC, I might as well throw in my own thoughts, observations, questions, etc.
I run a 6 lb barrel, charged with 10 Tb of 60/90 for coarse grind, as per Lortone instructions. Usually I find that after 5 days I have about 1/2 - 1 Tb of visible grit remaining, and fairly decent wearing on the rocks. I then add another 5 or 6 Tb directly into the "stew", let it tumble for 5 more days, then clean everything out. At this point there is usually 1/2 - 1 Tb of grit remaining (finer than 60/90, maybe more like 120/220, but still detectable at any rate).
Lately I've been noticing that if I include some bigger stones, and put in just enough rocks that things really crash around in the barrel (which seems to be 2/3 or 3/4 full to start), then after 4 days there will be no remaining grit. On my current load, things were really crashing about, so I opened it after 2.5 days, and surprise, no grit at all remained detectable, even with careful scraping of the sides and bottom of the barrel.
Many people seem to equate rapid grit breakdown with a good tumble, ie, things are progressing rapidly if the grit disappears. I'm not so sure. Seems to me that even with complete grit breakdown in 2.5 days, the stones hadn't shaped up as much as I would expect for 10 Tb of coarse grit.
I wonder if silicon carbide grit is in fact very brittle. So I'm thinking maybe the grit was just smashed to tiny pieces by the vigourous tumble, rather than actually wearing away while scraping the stones.
I recharged with another 10 Tb 60/90, then raised the barrel to about 90% full to stop the pounding inside the tumbler. Tonight, after 1 day of running like this, I notice no apparent grit breakdown, and virtually no rock smoothing either. So now it seems too slow, and I took out a few rocks tonight to try and correct this.
I don't think I'm offering any solution here, but I do have a question to anyone else who has explored this problem.... what is the ideal time that grit should last in order to ensure the optimal grind? It seems to me that when it breaks down very quickly then not much is accomplished, and when the grit breaks down very slowly then grinding is also rather slow, plus time becomes an issue. So what's the happy medium?
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JC
starting to spend too much on rocks
Member since September 2004
Posts: 107
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Post by JC on Jan 7, 2005 8:04:45 GMT -5
Thanks for the reply Rollingstone this is what I was talking about.
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Post by Cher on Jan 7, 2005 10:24:34 GMT -5
I just don't like finding a pile of grit in the bottom of the barrel so kept lowering the amount until I reached the point I was happy. I guess it's a matter of preference. I recharge my barrels every 3 or 4 days and can tell it's working, I add new rough each time I recharge to keep the barrel at optimum fullness. As long as it's working, doesn't seem to make sense to add more.
Maybe I'm wrong, maybe I should just "accept" that there will be a lot of grit left in the bottom of the barrel. Will adding more grit guarantee that the rough is going to wear down and be ready to move on to the next stage faster? OR just mean that I will go through the grit faster?
Cher
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Post by creativeminded on Jan 7, 2005 10:48:48 GMT -5
I did what you did Rosebud, when I started my 3#er I used what they recommended on grit amount and I had great results after 2 weeks, but had a lot of grit left over so I decided to drop the grit down to 2 tablespoons and I still get great results and no left over grit. Tami
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rollingstone
starting to spend too much on rocks
Member since July 2009
Posts: 236
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Post by rollingstone on Jan 7, 2005 12:26:08 GMT -5
To more directly answer JC's questions:
1. If the grit is all gone, if you can't even feel any grittiness on the rocks or in the mud that might accumulate on the bottom of the barrel, then a midweek recharge is a good idea because you aren't doing much but rolling stones around by themselves.
2. I just add more grit (and rocks to bring up the volume) for one time. I find that if I do this a second time I have increased the weight of the barrel too much, and the motor strains. Might even be straining a bit with one top-up, but hasn't hurt it after running for more than a year continuously like this.
3. Aqua (beryl) is significantly harder than jasper, and harder rocks will wear the grit down faster. See my earlier notes about what other factors might be breaking the grit down quickly.
4. Yes.
My thoughts anyway. Good luck!
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Post by puppie96 on Jan 7, 2005 13:00:14 GMT -5
Hey RS -- I've had 12-lb and 6-lb barrels for a few months. Seems like they do break down grit very quickly. I wonder too, is that because of using bigger rocks or what? But, I've never questioned that it was working efficiently while breaking down, since the rocks seem to shape up very quickly, too. Bigger rocks always seem to take longer regardless of the size of the barrel.
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rollingstone
starting to spend too much on rocks
Member since July 2009
Posts: 236
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Post by rollingstone on Jan 7, 2005 16:50:03 GMT -5
Pup, I was always pretty happy with 90-95% of the grit breaking down in 5 days -- seemed to give good wear on the rocks and was relatively fast (used to take about 7 days with a 3 lb barrel). This last load with 100% grit breakdown in 2.5 days, and very little wear on the rocks, kind of shook my confidence in associating fast grit breakdown with a good tumble. And it wasn't just the big rocks in there that didn't shape up as much as I would have expected from 10 Tb of 60/90, the small ones had the same problem.
So now I'm rethinking what is the best compromise between grit breakdown, good shaping on the rocks, and time. I guess right now I'd be happy to get back to 90-95% grit breakdown in 5 days, then recharge. But maybe even longer is better? How long is it taking for grit to break down in your barrels?
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Post by puppie96 on Jan 8, 2005 1:32:54 GMT -5
RS -- Is it possible this was a load of exceptionally hard rocks? I've had runs that seemed to do NOTHING on the first couple 60/90 weeks.
Length of time varies for me. Large barrels go very fast. Like complete breakdown in 5 days isn't unusual. But, recently I've been really working on patience, not looking too soon, etc. So I haven't been opening either the big or small barrels too much, and after 7 the grit is pretty usually all gone. If you've got any left at all after 5 days, it makes sense to me to leave it go. As someone said earlier in this thread, it hasn't stopped working though it may be at a finer grind, so why not?
I think the big issue is the water amount. I find this tricky. I'm careful not to overuse water, Lortone says below the top layer of rocks but I've found that's too much and sometimes a lot less is too much. This is somewhat of a puzzle when I open it up and find the rocks covered with water in 2 days when I could hardly see any when I closed the barrel. I pretty much think that most of these problems -- too watery slurry, grit not breaking down, not enough grinding -- are probably due to excess water. If I seem to be getting this after a couple of days I dump a lot of water off and a couple days later it will be slurried up (though sometimes too thick, so you have to check.)
And that's my take on it!
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llanago
fully equipped rock polisher
Member since January 2004
Posts: 1,714
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Post by llanago on Jan 8, 2005 7:56:12 GMT -5
pup, I definitely agree on the water! I have cut down on the water in the rotary tumblers and am getting much better results. In the vibe, when I have cut back on water, I get the ole rocks stuck to the bottom, so I am still going with 2 tbls of water even though the instructions call for 2 teaspoons. Weird isn't it, that other folks have success with less water in the vibe and I have problems. I wonder if it is the water, or maybe the heat and/or humidity? Curious.
llana
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Post by puppie96 on Jan 10, 2005 23:42:56 GMT -5
I don't know, when I don't put enough water in the vibe, or leave it go too long, it gets stuck. Bad, sometimes, really bad. On the other hand if I started with 2TBSP of water it would be splashing all over the place and the stuff wouldn't grind at all. Could be the big factor here is the type of rock.
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rollingstone as guest I guess
Guest
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Post by rollingstone as guest I guess on Jan 11, 2005 2:31:16 GMT -5
Thanks for the water comment, that's something I should probably pay more attention to or experiment with. I generally like to seal everything up and leave it go for 5 days untouched. After 5 days, I notice that the rocks are mostly beneath the water too, so I have cut back a bit on the water, but maybe I should be more aggressive about this. Or open the barrel every couple of days and adjust water and rock levels. It's really pretty easy to do, particularly since I'm only running one barrel, I just make it out to be a big deal in my head.
For coarse grind, if I can't feel any grit when I rub the mud or rocks between my fingers, then I figure the grit has broken down too much to still be doing any coarse grinding, so that means it's time for a recharge. I don't want it to be doing fine grinding at that point, that isn't moving things ahead.
Maybe it was on another thread where someone said it was better to clean out completely each time instead of just adding more grit? That is probably true, but I get lazy and substitute just adding extra grit for every second clean-out. In winter here it's also a matter of convenience. My current tumble should be cleaned out Wednesday, but the forecast is for a high of -26C (-15F), with wind chill of -45C (-49F), nastiest day of the winter so far. Since I do my cleaning outdoors, I think I'll clean things out a day early on Tuesday, when it isn't so ugly outside. So the weather plays a role in winter for me. I'm even tempted to just add in yet another round of adding grit since Tuesday's high of -17C (+1F) doesn't sound very appealing to be outside splashing in the water either, but the barrel is getting a bit heavy now and does need a cleaning. Time for a good shot of the warm El Nino winter they were promising....
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Post by puppie96 on Jan 11, 2005 3:19:20 GMT -5
Well, my hose unfroze this weekend, so again for a couple of days I've been able to rinse stuff outside. Nice change. On new years day I was barefoot out there, then after a few days cold, again I'm out rinsing in a short sleeve tshirt. Weird year for weather.
When I can't rinse them outside I rinse them in a colander over a bucket in the basement then carry the bucket outside to dump it. More work but it works.
What happens to me if I just keep adding grit without rinsing is that a whole bunch of sludge/grit builds up and semi-solidifies at the bottom of the barrel. So I always wash it out. Besides, I like to look at the rocks.
I've been making an effort to be patient, stop looking all the time, etc. BUT I found out that it really is important to check after a day or two and make sure you are getting slurry and don't just have bunches of water in there. Otherwise you get 5 days in and THEN find out this not-happy news.
-sigh- So many traps for the unwary.
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