entropy
having dreams about rocks
Member since June 2020
Posts: 71
|
Post by entropy on Jun 27, 2020 20:38:43 GMT -5
Thanks for the input guys.
Large tumblers (tumbling large rocks) simply does not work, because the rocks are subject to bruising.
This saved me a lot of aggravation.
|
|
EricD
Cave Dweller
High in the Mountains
Member since November 2019
Posts: 1,142
|
Post by EricD on Jun 27, 2020 20:39:36 GMT -5
Thanks for the input guys. Large tumblers (tumbling large rocks) simply does not work, because the rocks are subject to bruising. This saved me a lot of aggravation. Tumbling one large rock does work
Edit: You could likely tumble a 28" rock in your barrel, but alone, and with a lot of engineering involved. At the end of the day (or 10 years) you would have a really big, and really shiny rock. Your labor would be enough to buy a car, maybe a house.
I do not see how tumbling a really big rock would ever work. However if you want to tumble a single, yes, single, 8" rock, see Diamond Pacific's 65T
|
|
|
Post by knave on Jun 27, 2020 20:41:35 GMT -5
jamesp has had success with longer, smaller diameter barrels.
|
|
entropy
having dreams about rocks
Member since June 2020
Posts: 71
|
Post by entropy on Jun 27, 2020 21:13:11 GMT -5
From my limited research on the subject - large scale for-profit rock tumbling operations appear to use multiple sets of tumblers (dozens at a time) - driven by long jackshafts.
I haven't found any examples of large diameter tumblers (at least for polishing rocks). Bruising rocks is not a design concern for large diameter industrial rock tumblers . . .
|
|
EricD
Cave Dweller
High in the Mountains
Member since November 2019
Posts: 1,142
|
Post by EricD on Jun 27, 2020 21:24:26 GMT -5
From my limited research on the subject - large scale for-profit rock tumbling operations appear to use multiple sets of tumblers (dozens at a time) - driven by long jackshafts. I haven't found any examples of large diameter tumblers (at least for polishing rocks). Bruising rocks is not a design concern for large diameter industrial rock tumblers . . . Bruising rocks is a design concern for any tumbler
|
|
entropy
having dreams about rocks
Member since June 2020
Posts: 71
|
Post by entropy on Jun 27, 2020 22:07:36 GMT -5
The above link shows a large industrial rock tumbler. Judging by the operating noise & speed of the machine, I would argue that bruising the rock is not a design concern. I'm not exactly sure exactly what they're trying to achieve with this tumbler. I presume they're trying to make the rocks less jagged. If they're trying to actually crush the rock into smaller pieces, an orbital rock-crusher would be 99% more effective than a tumbler. But I digress. My idea (the whole purpose of this thread) was to build a 30" diameter version of this machine (or one similar to it) - and run it slow, with plenty of filler & slurry, and attempt to polish larger rocks.
This link (above) is advertised as a rock tumbler. Honestly it looks more like a ball-mill to me. But who knows? It's big, and it would probably bruise rock - if attempted to be used for polishing.
Here's another rock tumbler. Again, not sure what the purpose is. It looks like they've put big chunks of scrap concrete into it. Again, if the design intent is to reduce the size of the concrete, a rock crusher would be faster, and more effective. This machine would likely bruise rocks.
This one is pretty cool. Seems to be turning a little fast - for polishing rocks. What is the purpose of this machine? Is it a parts cleaner? Honestly, I don't know???
|
|
|
Post by pauls on Jun 27, 2020 22:20:41 GMT -5
Wow that is going big. I tumble in Liquid propane gas tanks, steel is really not a problem, my batch size is about 30 Kilograms, that's plenty, any bigger you run into weight issues, and just huge amounts of rock to feed it. I would say those machines are making rounded rocks for landscaping. I have seen a picture of a large tumbler made from a truck tyre, it would need babying I think as it is not sealed so would dry out quickly.
|
|
|
Post by rockpickerforever on Jun 27, 2020 22:50:21 GMT -5
|
|
EricD
Cave Dweller
High in the Mountains
Member since November 2019
Posts: 1,142
|
Post by EricD on Jun 27, 2020 23:28:24 GMT -5
If you are not concerned about bruising the rock or fracturing it, than any method will do. Then you can tumble any way you please and be gleeful of the outcome.
|
|
entropy
having dreams about rocks
Member since June 2020
Posts: 71
|
Post by entropy on Jun 28, 2020 0:12:25 GMT -5
rockpickerforever, I am intrigued by your tire tumbler. What is the tire size? What RPM do you operate it at? How many pounds of rock do you fill with? What is the water-level? I'm assuming the bead is the limit for filling? More importantly - can you accomplish all four stages of rock tumbling with that tire (through to the polish stage) - or is the tire for rough-cutting only?
The inflatable ball is a great idea. I've seen a few pictures of tire tumblers that others have made, and the attempts to seal the bead were crude and not quality to say the least (wood, boards, screws, glue, etc). Inflating a ball is a low-cost ingenious solution.
The only tumbler I own is Tru-Square Model B. It has about a 9.25" diameter drum, and turns at 21 RPM. This equals a tangential velocity of about 10.2 in/s. I'm assuming this is the sweet-spot for tumbling rocks, where smaller diameter tumblers turn at a higher rpm, and larger diameters turn at a slower RPM - all to maintain the same 'approximate' 10 in/s drum velocity. Is this true for a tire tumbler also?
Big old tires can be had for next to nothing. The most expensive consumable (aside from the grit and electricity) would be purchasing replacement exercise balls.
|
|
|
Post by rockpickerforever on Jun 28, 2020 0:24:01 GMT -5
rockpickerforever, I am intrigued by your tire tumbler. What is the tire size? What RPM do you operate it at? How many pounds of rock do you fill with? What is the water-level? I'm assuming the bead is the limit for filling? More importantly - can you accomplish all four stages of rock tumbling with that tire (through to the polish stage) - or is the tire for rough-cutting only? The inflatable ball is a great idea. I've seen a few pictures of tire tumblers that others have made, and the attempts to seal the bead were crude and not quality to say the least (wood, boards, screws, glue, etc). Inflating a ball is a low-cost ingenious solution. The only tumbler I own is Tru-Square Model B. It has about a 9.25" diameter drum, and turns at 21 RPM. This equals a tangential velocity of about 10.2 in/s. I'm assuming this is the sweet-spot for tumbling rocks, where smaller diameter tumblers turn at a higher rpm, and larger diameters turn at a slower RPM - all to maintain the same 'approximate' 10 in/s drum velocity. Is this true for a tire tumbler also? Big old tires can be had for next to nothing. The most expensive consumable (aside from the grit and electricity) would be purchasing replacement exercise balls. entropy, those are questions you will need to ask the owner, jamesp. That is something he was fiddling with years ago. I only reposted it because you had specifically mentioned using tires, and how to plug the hole. James, are you up to answering some of his questions?
|
|
entropy
having dreams about rocks
Member since June 2020
Posts: 71
|
Post by entropy on Jun 28, 2020 0:56:14 GMT -5
Pauls, what size propane tanks do you use (aka convert) for rock tumbling? (in US gallons, or liters - not sure what they use down there). I guess a better question would be - what's the OD (inches) of the cylinder, and how fast do you turn it (RPM)? Do you put any ribbing on the inside of the tank to encourage tumbling, or does it retain a smooth steel surface throughout?
For a standard 5 gallon US propane tank, I was thinking one could weld a piece of 4" NPS Schedule 40 steel pipe onto the cylinder's end (prepping/cutting the valve-end out with a 4.5" hole) - this way a 4" rubber cap can be used to seal the tank (similar to how some PVC tumblers are sealed). Old propane tanks can be had for next to nothing - literally for nothing when they're discarded for recycling. This seems like a very inexpensive alternative to purchasing name-brand tumbler barrels.
The biggest potential downside would be noise. Do non-rubber lined propane tank tumblers rattle loudly during operation?
|
|
jamesp
Cave Dweller
Member since October 2012
Posts: 36,154
|
Post by jamesp on Jun 28, 2020 5:41:56 GMT -5
Maybe I am not one to address this subject because I use sticky clay as a slurry thickener. Lol rockpickerforever Jean. Thanks for pulling this ancient archive. Cool subject matter entropy, welcome to RTH. The tire tumblers don't tumble like a barrel because they can not (as far as I know) be filled to 60 to 85% full. Tire tumblers can slip due to low fill. Barrels way less likely to slip. Mine beat the rocks up terribly. No thanks. SDR 35 PVC is much harder and slicker and yes the rocks will slide at slower rotation speeds. Simply increase speed. sdr 35 wears fast. Steel, HDPE, Sch 40 PVC achieves a rough surface where stage 1 grit roughens the inside surface and will not allow rocks to slip even without kickers installed. Kickers usually short lived by the way. The tire tumbler in the photo was quickly converted to a barrel tumbler. The slant tumbler makes the best sense for a large tumbler. Keep in mind it is about impossible to bruise small rocks. Once you start adding rocks over 2 to 3 inches impacts become an issue. entropy, I believe the big tumbler in your first photo was being used on Montana agates under 1 inch. I believe nowyo made propane tank tumblers. Seemed like one of the welded seams in the tank separated. They can be had cheap. Why not weld up another ? - limited life but worked great as a tumbler aside from noise of course. Yes the rubber cap design should work entropy. I won't tumble without a barrel not set up with a quick fernco cap.
|
|
jamesp
Cave Dweller
Member since October 2012
Posts: 36,154
|
Post by jamesp on Jun 28, 2020 6:04:08 GMT -5
jamesp has had success with longer, smaller diameter barrels. Main reason for the longer length was because of the use of pipe stock Evan. Whether a 10 pound barrel that is short and with big diameter or long with small diameter is best I always wondered. The tumbling path would be very different due the the effect of the vertical walls being close together in the tall barrel. I must say a 6 inch inside diameter barrel rotating unusually fast is both gentle and very fast way round rocks in step 1 without bruising. Because the rocks never fall far as they do in a larger diameter barrel. This truth is revolutionary IMO.
|
|
|
Post by knave on Jun 28, 2020 6:06:51 GMT -5
This truth is revolutionary. I can see what you did there.
|
|
|
Post by nowyo on Jun 28, 2020 6:12:46 GMT -5
Blasts from the past. Yeah, I made a propane tank tumbler, standard 5 gallon tank. Cut a hole in the top, welded on about 2.5 inches of inch Sched 40 pipe, used rubber cap. Worked fine, but it was loud. At our place in Wyoming it wasn't a problem but here in Nevada we have actual neighbors, most of the doing shift work. The original barrel lasted almost two years before it started wearing through running nothing but 36 grit. Made another barrel, and still have it. Really about as cheap and easy a way to make barrels as there is. On the original I welded two pieces of 3/8 rod inside at 180 degrees for kickers, on the second barrel I left those out. No difference in performance, wouldn't bother with them. Sure could get a bunch of rocks through coarse to keep things moving along.
Russ
|
|
jamesp
Cave Dweller
Member since October 2012
Posts: 36,154
|
Post by jamesp on Jun 28, 2020 6:23:29 GMT -5
Thanks for engaging Russ. I always admired your steel barrels.
|
|
jamesp
Cave Dweller
Member since October 2012
Posts: 36,154
|
Post by jamesp on Jun 28, 2020 6:39:31 GMT -5
This truth is revolutionary. I can see what you did there. Well I do glass at 80 rpm and use SiC 10(using SiC 10 mainly for the time release effect) in the 6 inch barrels. Never came close to shaping it so fast without a single bruise. Lots of high speed rubbing cycles with out the risk of fall impacts in larger diameter barrels. The need to use smalls for padding is virtually eliminated. Roll nothing but target tumbles in the limited barrel space. Shapes a big rock surrounded 100% by smaller 1 inch rocks incredibly fast. The speed may not go over well with product liability issues on a mass produced product. And the increased noise. Home builders should consider the high speed/small diameter approach.
|
|
|
Post by rockpickerforever on Jun 28, 2020 7:04:58 GMT -5
Maybe I am not one to address this subject because I use sticky clay as a slurry thickener. Lol rockpickerforever Jean. Thanks for pulling this ancient archive. You're welcome, James. Thanks for jumping in when I summoned you, lol. I knew the tire tumbler was far from ideal (bruising rocks), but you had fun with it. Always trying different things!
|
|
|
Post by HankRocks on Jun 28, 2020 7:59:10 GMT -5
Blasts from the past. Yeah, I made a propane tank tumbler, standard 5 gallon tank. Cut a hole in the top, welded on about 2.5 inches of inch Sched 40 pipe, used rubber cap. Worked fine, but it was loud. At our place in Wyoming it wasn't a problem but here in Nevada we have actual neighbors, most of the doing shift work. The original barrel lasted almost two years before it started wearing through running nothing but 36 grit. Made another barrel, and still have it. Really about as cheap and easy a way to make barrels as there is. On the original I welded two pieces of 3/8 rod inside at 180 degrees for kickers, on the second barrel I left those out. No difference in performance, wouldn't bother with them. Sure could get a bunch of rocks through coarse to keep things moving along. Russ You mentioned that you used the propane tank tumbler to move rocks through the coarse stage. Did you use it do the following stages, or after coarse move the rocks to a different, maybe more conventional smaller tumbler? Henry
|
|