dug
off to a rocking start
Member since March 2022
Posts: 21
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Post by dug on May 20, 2023 12:04:37 GMT -5
I am relatively new to this hobby. I'm getting pretty confident with the results from my 3lb barrels and from my vibratory tumbling. But I've got a couple of larger barrels and I'm still trying to find some consistency. I'm currently using a Lortone 6lb barrel for the rough stage. It's running on a home-built tumbler that spins the barrel a little faster than the Lortone QT-6 would. I'm filling the barrel about 2/3 full, and I'm adding a bunch of plastic pellets since I have more larger rocks than smaller. Lortone calls for 10 tbsp of 80 grit for a 6lb barrel. I'm using 6 tbsp of 46/70. I'm cleaning and refilling the tumbler every week(ish).
I'm finding a few issues that I question. First, at the end of a week there is still some visible grit left in the slurry. The slurry is still a bit gritty. With a 3lb tumbler and 60/90 grit, I don't see this. The grit is all consumed. Second, I don't feel that the tumbler is proceeding as quickly as it should. Maybe this comes down to the scale of the rocks -- larger rocks fit in the 6lb, but need more time. Or maybe it really is slower than it could be. My impression from earlier experiments with a 12lb barrel make me think I should expect quicker grinding. So, questions... Are the plastic pellets the issue? I have used ceramic before, but while they work well in a vibratory I find they get destroyed quickly in a large barrel rotary. If I don't have a lot of smaller rocks, should I use plastic pellets as filler, or just leave it without filler? Does the narrow profile of the Lortone 6lb barrel make it grind more slowly than the 12lb barrel? When you are cleaning your larger barrels weekly, does the grit get completely consumed? What grade of grit and how much do you use in your 6 or 12lb barrels? Thanks for any input.
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tkvancil
fully equipped rock polisher
Member since September 2011
Posts: 1,546
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Post by tkvancil on May 20, 2023 13:52:10 GMT -5
Plastic pellets are meant to cushion and "slow the action". Pellets probably your problem, the barrels are good as far as I've experienced. The rest of your formula sounds okay.
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dillonf
fully equipped rock polisher
Hounding and tumbling
Member since February 2022
Posts: 1,577
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Post by dillonf on May 20, 2023 14:36:00 GMT -5
I have a QT12 and a QT 6, and I believe they are equally efficient. I agree with what tkvancil said above. I only use ceramic, but it is fairly costly. I have read on the forum that some folks use pea gravel as filler, because it is more economical but I haven't tried it. I think with a 46/70 grit you may wan't to add some additional water and let it run for 2 weeks at a time. I used to use 80 grit SiC and turn my tumblers over weekly with pretty predictable results. I then bought 25lbs of 60/90 grit and used my same methods, but found (like you) that not all my grit was breaking down after 1 week. So, I reached out on the forum here and got some good suggestions - in the end I decided to let my tumblers run for 2 weeks. I add 6 rounded teaspoons ( correction) tablespoons of grit and a teaspoon of borax in the 6lb barrel, and I have the water almost to the level of the rocks (I used to have it about 1/2 inch below the rock level). It is actually much more efficient as I only have to do big cleanouts once every 2 weeks! best of luck!
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dug
off to a rocking start
Member since March 2022
Posts: 21
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Post by dug on May 20, 2023 15:40:10 GMT -5
Thanks for the feedback! I will ditch the plastic pellets and either try without filler, or use some inexpensive landscaping rocks for filler. I add 6 rounded teaspoons of grit and a teaspoon of borax in the 6lb barrel, and I have the water almost to the level of the rocks 6 teaspoons? That's really not very much grit. I believe Lortone calls for 10 tablespoons for the 6lb barrel.
I've got a bunch of experiments planned. I guess I need to plan another one -- compare using 6 tsp versus 6 tbsp in a 6lb barrel.
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dillonf
fully equipped rock polisher
Hounding and tumbling
Member since February 2022
Posts: 1,577
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Post by dillonf on May 20, 2023 16:11:21 GMT -5
Thanks for the feedback! I will ditch the plastic pellets and either try without filler, or use some inexpensive landscaping rocks for filler. I add 6 rounded teaspoons of grit and a teaspoon of borax in the 6lb barrel, and I have the water almost to the level of the rocks 6 teaspoons? That's really not very much grit. I believe Lortone calls for 10 tablespoons for the 6lb barrel.
I've got a bunch of experiments planned. I guess I need to plan another one -- compare using 6 tsp versus 6 tbsp in a 6lb barrel.
Yes you are right I meant tablespoons not teaspoons . . . sorry. With them being rounded I'm guessing I have 6-8 tblspns per barrel
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Post by Starguy on May 20, 2023 17:55:29 GMT -5
dugYou can ditch the plastic pellets in my opinion. They are good at minimizing impacts in later stages. I like a little impact shaping in my bigger coarse tumblers.
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Post by velodromed on May 21, 2023 0:19:30 GMT -5
I am relatively new to this hobby. I'm getting pretty confident with the results from my 3lb barrels and from my vibratory tumbling. But I've got a couple of larger barrels and I'm still trying to find some consistency. I'm currently using a Lortone 6lb barrel for the rough stage. It's running on a home-built tumbler that spins the barrel a little faster than the Lortone QT-6 would. I'm filling the barrel about 2/3 full, and I'm adding a bunch of plastic pellets since I have more larger rocks than smaller. Lortone calls for 10 tbsp of 80 grit for a 6lb barrel. I'm using 6 tbsp of 46/70. I'm cleaning and refilling the tumbler every week(ish).
I'm finding a few issues that I question. First, at the end of a week there is still some visible grit left in the slurry. The slurry is still a bit gritty. With a 3lb tumbler and 60/90 grit, I don't see this. The grit is all consumed. Second, I don't feel that the tumbler is proceeding as quickly as it should. Maybe this comes down to the scale of the rocks -- larger rocks fit in the 6lb, but need more time. Or maybe it really is slower than it could be. My impression from earlier experiments with a 12lb barrel make me think I should expect quicker grinding. So, questions... Are the plastic pellets the issue? I have used ceramic before, but while they work well in a vibratory I find they get destroyed quickly in a large barrel rotary. If I don't have a lot of smaller rocks, should I use plastic pellets as filler, or just leave it without filler? Does the narrow profile of the Lortone 6lb barrel make it grind more slowly than the 12lb barrel? When you are cleaning your larger barrels weekly, does the grit get completely consumed? What grade of grit and how much do you use in your 6 or 12lb barrels? Thanks for any input.
I’d love to see pictures of your home grown tumbler when you have a chance!
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Post by rmf on May 21, 2023 2:26:10 GMT -5
dug Fill the tumbler 75% full, take out the plastic pellets and add an equal volume of smaller rocks. They help carry the grit and make mud. Don't clean out the tumbler every week. the mud buildup from grinding helps make grinding more efficient. Plus you do less work making tumbling more enjoyable. Do not sweat the left over grit in the coarse grit. Wash stones over a 5 gal bucket, leftover coarse grit falls to bottom and you can recycle it. Tumble coarse rocks till they are rounded like you like them. I have tumbled for a month and still have left over 46/70. Does the narrow profile of the Lortone 6lb barrel make it grind more slowly than the 12lb barrel? sounds like an interesting research project for you. Please report back your findings. What grade of grit and how much do you use in your 6 or 12lb barrels? I always followed the Lortone recommendation except when tumbling a month I added 50% more. since I was going to wash out and recycle left over grit I did not worry about having too much.
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dug
off to a rocking start
Member since March 2022
Posts: 21
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Post by dug on May 22, 2023 12:34:31 GMT -5
Thanks for the input. I will acquire a bag of landscaping pebbles to use, instead of plastic pellets, when I don't have enough small material in a load. I will also experiment running without any smaller fill -- just larger rocks -- and see what happens. I'll stick with 6tbsp of 46/70 for a 6lb barrel. I like the weekly schedule for cleanouts, particularly when I've got some smaller stuff in the barrel -- don't want to grind it to nothing. When I'm doing my weekly cleanouts, I am fussy about cleaning around the barrel seal. I don't put any effort into cleaning leftover grit/slurry out of the barrel itself, but usually by the time I finish cleaning the seal there's not much slurry left. I have been meaning to put together a post about the home-built tumbler, but like most projects I'm never actually satisfied that it's finished! I'll get some photos up at some point. Again, thanks all!
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Post by Starguy on May 22, 2023 13:26:03 GMT -5
dug Doug It sounds like you are getting rock tumbling figured out. In all honesty, I don’t think there is any perfect tumbler recipe that works every time. There are too many variables from load to load. The important thing is to keep them rolling. As qualifiers, I am rotary only. I tumble mostly agate, but have finished some nice batches of sensitive rocks. I try to do 7 day cleanouts. I’ve gone as short as 4 days and as long as a couple months between opening barrels. In rotaries, coarse grit is getting pretty worn out after 4-5 days. I use 7 days as much as possible just to maintain a standard and take that variable out of the equation. For coarse batches, it doesn’t seem like you need anything but rocks, water and grit. If the slurry is thick after 7 days, it was a successful grind. The thicker the better. In my opinion you don’t need thickeners, cushioning or any additives in coarse. You learn how well you are doing every time you open a barrel. Over the years, I’ve had my share of disappointing cleanouts but the good ones make me keep the rocks rolling. Since I run multiple barrels, I need to keep notes. I added a column for comments to my notebook so that I can add details about slurry quality or anything else I notice. Please note that you get a very thin slurry when you forget to add grit. Don’t ask me how many times I’ve discovered this fact. Good luck and have fun. Looking forward to some photos of your work.
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hypodactylus
spending too much on rocks
Member since July 2021
Posts: 431
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Post by hypodactylus on May 22, 2023 16:37:16 GMT -5
I know I am late to the party, but I use left over stage 1 grit as a sign that I didn't get good grinding action, or I simply added too much grit. There are a number of factors at play, as mentioned in this thread; fill level, media, rock types, rock sizes, etc. I have used this idea to help me figure out how much grit to use in each barrel and, honestly, it can vary quite a bit. Generally, I have found that I can use more grit in larger barrels and still have it all broken down by the end. I currently try to fill my larger barrels literally between 2/3 and 3/4 full (around 72% or so). I do not use 'tumbling media' in stage one, but I make sure I have a range of rock sizes and I add a fair amount of smaller rocks (ceramic media size) that I keep around for this purpose. For reference, my current grit targets (for rocks mostly around 7 Mohs): I use 2 cups (32 Tablespoons) of 45/70 grit for a 1 week run in my QT12 barrel. 3 cups (48 Tablespoons) and a bit more water for two week runs. I use 1/2 cup (8 Tablespoons) of 60/90 grit for a 1 week run in my 45C barrel. 3/4 cup (12 Tablespoons) and a bit more water for two week runs.
My takeaways from your post: larger rocks take a lot longer in stage 1, don't use plastic pellets (at least not in stage one), check your fill level, and always check for leftover grit to see if you need to adjust the amount (otherwise, you are just wasting your money).
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dug
off to a rocking start
Member since March 2022
Posts: 21
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Post by dug on May 29, 2023 16:32:07 GMT -5
I’d love to see pictures of your home grown tumbler when you have a chance!
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Post by Bob on May 30, 2023 14:01:14 GMT -5
Thanks for the input. I will acquire a bag of landscaping pebbles to use, instead of plastic pellets, when I don't have enough small material in a load. I will also experiment running without any smaller fill -- just larger rocks -- and see what happens. I'll stick with 6tbsp of 46/70 for a 6lb barrel. I like the weekly schedule for cleanouts, particularly when I've got some smaller stuff in the barrel -- don't want to grind it to nothing. When I'm doing my weekly cleanouts, I am fussy about cleaning around the barrel seal. I don't put any effort into cleaning leftover grit/slurry out of the barrel itself, but usually by the time I finish cleaning the seal there's not much slurry left. I have been meaning to put together a post about the home-built tumbler, but like most projects I'm never actually satisfied that it's finished! I'll get some photos up at some point. Again, thanks all!
I also read your original post. I have been running 3 x 12lb barrels and 3 x 6lb Lortone barrels continuously for years. And some larger barrels too. I recommend cutting back on your RPMs to factory RPMs. 46-70 grit okay for rough grind as long as the grit is well-mixed. That was mentioned because my experience is that buying 50 or larger alone will decrease production. All else being the same, processing takes about twice as long in a 6lb as opposed to 12lb barrel. What I mean is that even with weekly cleanouts, a 6 might take a month to do same work on rocks that would get done in 2 weeks in a 12. But the grit cost is about the same per rock finished. The only reason I continue to run 6lb barrels is it lets me control certain small batches of certain rocks and is a little easier on sensitive material. For instance I collected certain orange rocks in New Mex recently and don't have enough for a 12lb barrel. For me, plastic pellets in grits larger than 220 greatly decrease production and can cause leftover grit after a week--not sure why. Landscape pebbles are okay as long as are quartz level hardness and not softer. I find thumbnail size or slightly smaller ideal. Concentrating your attention on the seal and not caring about barrel body and leaving some slurry in there (maybe 1/4") is what I do too if the grit size stays the same. But if going to a finer grit, I rinse out the barrel just in case a piece of new grit fell out of the seal area when cleaning it into the barrel. Lastly is one kind of odd result I've observed. Let's say I have a lot of rocks golf ball size or slightly smaller--I'm talking 1 - 1.5". If I put them into a 12lb barrel and only them, there is almost always a little impact damage so I have to use some quartz smalls as filler. But I can put them in a 6lb barrel even w/o filler and rarely any damage. This even though the barrels are same RPMs on same tumbler shafts. This has always puzzled me since the barrels have same diameters. I take advantage of this sometimes to be hard on rocks in the first week to discover hidden fractures that might cleave off pieces which I want to happen sooner rather than later.
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