herchenx
Cave Dweller
Member since January 2012
Posts: 3,360
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Post by herchenx on Apr 27, 2013 22:22:08 GMT -5
About a year ago I started running a large tumbler. I think it is rated at 90#, it weighed 120# after adding the grit and water last time.
My last attempt was not terribly satisfying. I ran it using a couple recipes - first based on scaling up from my 12# tumbler, then based on weight/grit weight. I tried adding more grit without cleaning as was suggested but I don't know if that helped or not. I also did a flush/rinse once but the end result was always the same:
In the end it caked the barrel wall with 2-3" of cemented rocks and the center remained with a nice slurry and the rocks tumbling normally.
I'm looking for a better way to do it this time. I have a ~3/4 full barrel of all sizes of agates and pet wood from my last trip out. I think it is around 100# right now and I am in no rush so I'd like to be able to let it run for longer between cleaning.
Also, should I go to a different grit than 60/90? I will still run coarse only in the rotary, and then feed my vibe in 10# batches, would I be ahead to get a much coarser grit? I have a harbor freight in town and I think they have SiC for sandblasting relatively inexpensive, in larger grits.
Thanks for any help, I'd like to fire it up tomorrow and leave it running for a few weeks without having to recharge it right away.
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quartz
Cave Dweller
breakin' rocks in the hot sun
Member since February 2010
Posts: 3,339
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Post by quartz on Apr 27, 2013 23:36:41 GMT -5
We run a 50# load in a 12" PVC barrel 12" long {5 gallons}, and haven't had any trouble such as you mention. I fill 3/4 full, use one pound of grit per gallon of barrel capacity, 5lbs., add the grit to the top of the load, and add hot water to just the bottom of the top layer; and a couple tbs. Borax. After a lot of fiddling and listening, 17 R.P.M. is the "sweet speed". We mostly run rough hillside mtl. Pet. wood and quartz chunks, and have found 16 grit to be very effective for roughing , generally two runs of 10 days each before 80 grit. No cleaning 'till 80 is done, I just add the grit. I'd be thinking you are running maybe too much grit or not enough water.
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jamesp
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Member since October 2012
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Post by jamesp on Apr 28, 2013 20:53:37 GMT -5
I never had a build up like that either.Try 1/2 the grit.If there is no grit then there can be no concretion....Larry's menu of 1 lb per gallon sounds good.I would bet $21.37 that you got too much grit.And you know to fill w/water to just below.It would really have to be turning fast to stick centrifugally.Turning too slow should not cause trouble.Could the rocks be sliding?I had a tire tumbler that the rocks never tumbled.They just climbed up and slid back down.I fell down laughing at my creation.BUT,big diameter round barrel tumblers can have a sliding load because of the long slope up.Run for a few minutes on the very dry side and get paste started may solve sliding.Tell what diameter it is. Grit size makes little difference w/that issue.
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herchenx
Cave Dweller
Member since January 2012
Posts: 3,360
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Post by herchenx on Apr 28, 2013 21:10:28 GMT -5
It has an octagonal barrel so I don't think sliding is an issue. It is a commercial unit so I don't have any control over the speed. I forget now how much grit I used, it was a lot.
I am looking for sources of courser grit now locally. All I have on hand is 60/90 sic. Turns out the local Harbor Freight doesn't even carry SiC.
Sent from my phone.
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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 Apr 29, 2013 0:37:28 GMT -5
In a big barrel like that you could certainly start with 46/70 grit, probably even coarser.
To me, your main problem sounds like not enough water. I think that the slurry is getting too thick and it then cakes on the sides of the barrel along with whatever rocks and grit get embedded.
Big barrels have aggressive action so grind things pretty quickly. I would start with yor usual set-up but go pretty light on the water. Then I would open the barrel after a few days (2 days?, 3?, 5?... will require some experimenting) and add more water to thin the slurry and prevent it from getting thick where it will cake onto the sides of the barrel. You will have to do this every few days to maintain the slurry thick enough to do its job but not so thick that it cakes onto the barrel. No guarantees, but that's my take on it.
-Don
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jamesp
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Member since October 2012
Posts: 36,154
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Post by jamesp on Apr 29, 2013 6:07:25 GMT -5
Is that tumbler made for rock John?Could it be designed for tumbling other materials?I am not aware of a factory made lapidary tumbler that size unless it has two 40 pound barrels.Sounds like a real bruiser.I run two 30 pound barrels constantly.And stock pile them.Then two 16 pounders can finish them faster than they can put out.So i often run just one 16 pounder and pick and choose what gets finished.All 4 work me to death! It is great idea to have a large passive tumbler for step 1.
I have been tumbling baseball size coral lately to remove a soft limestone coating on it about 1/4 to 1/2 inch thick.So the load is 40 percent by weight white mud in a day.Starts out rumbling loudly.Four hours later you can hardly hear it cause the slurry went from clean water to thick mud.I am right there ready to clean it out so it does not concrete itself.Concrete itself and cause imbalance and cause the barrel to stop spinning and ruin my barrel against the spinning shafts.
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herchenx
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Member since January 2012
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Post by herchenx on Apr 29, 2013 9:00:38 GMT -5
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jamesp
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Member since October 2012
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Post by jamesp on Apr 29, 2013 9:43:06 GMT -5
Wow.I am aware of that machine-sweet.You gotta get it going.What have you concluded at this point?
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Steve
has rocks in the head
Member since June 2005
Posts: 506
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Post by Steve on Apr 29, 2013 10:40:38 GMT -5
I wonder if you had too much soft pet wood that broke down.
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herchenx
Cave Dweller
Member since January 2012
Posts: 3,360
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Post by herchenx on Apr 29, 2013 10:47:54 GMT -5
Well the last time I ran it, it was all lake Superior and Bahia, I didn't run anything soft.
I'm looking for local sic in something coarser than the 60/90 I have now, once I find some, I'll start it up.
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Deleted
Deleted Member
Member since January 1970
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Post by Deleted on Apr 29, 2013 11:56:06 GMT -5
JOhn try this company in Denver. I found nothing in Fort Collins. www.toolsforconstruction.com/If they don't sell abrasives, then they almost certainly will be able to refer you to someone who does. Grit Blasting supply is your target industry. Or here: In Cheyenne, WY www.applied.com
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quartz
Cave Dweller
breakin' rocks in the hot sun
Member since February 2010
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Post by quartz on Apr 29, 2013 12:13:12 GMT -5
Man, that's some tumbler! Don't suppose it is in a place where it could possibly freeze, just a thought. Lot colder there than here. I run ours in an insulated shed, motor keeps it at about 50 deg. inside, even at 16 outside. Check industrial suppliers for grit. Larry
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herchenx
Cave Dweller
Member since January 2012
Posts: 3,360
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Post by herchenx on Apr 29, 2013 12:28:05 GMT -5
Thanks for all the help folks. 'gunner, called both those places and several others, folks have ao, garnet, glass, sand buy everyone scratches their heads at sic.
The garage is warm enough that it doesn't freeze, we may get more snow yet but the deep freeze is done.
Still looking for sic locally, may end up ordering online if there is no other option.
Sent from my phone.
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herchenx
Cave Dweller
Member since January 2012
Posts: 3,360
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Post by herchenx on Apr 29, 2013 12:49:16 GMT -5
Well Grainger has sic, but only 120 and 200...
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Post by MrP on Apr 29, 2013 15:14:03 GMT -5
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,154
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Post by jamesp on Jun 16, 2013 16:18:27 GMT -5
MrP,I just bought 50 pounds 30/60 from Miles Supply.I like this blend for my heavy tumblers.It was cheap.
John Herchenx,do not be surprised if your grit is completely crushed to nothing in 4-6 days.Those heavy loads can flat use grit quick.Also grinds rock quick.
I started with an attitude of let it roll for 10-12 days but-i feel like i was just wasting electricity after day 6. No doubt,that heavy load in there was making 600 grit out of 46 in 4 days-sure of it.
I am moving from a 8 inch to 12 inch (PVC) barrels.Rotating slow say 15 RPM.For doing 200-400 gram rocks,also.Slow, to reduce impact of those heavy rocks.I am lucky that the coral does not frost easy.But i like heavy grind more than fast grind for big stuff. The bigger the barrel the higher the slippage.I like that octagon/hexagon shape on that barrel.The slow turning 8 inch PVC barrels slip on the slow shafts a little causing wear.I will put kickers in the 12 incher-somehow.
I think i am evolving into Larry's(Quartz) rig.He is the master of the big rigs.
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quartz
Cave Dweller
breakin' rocks in the hot sun
Member since February 2010
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Post by quartz on Jun 17, 2013 0:07:40 GMT -5
I saw that, and consider it a compliment, thank you. But I am a little embarrassed at the word "master". Be it known I'm no more than a dedicated tinkerer.
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The Dad_Ohs
fully equipped rock polisher
Take me to your Labradorite!!
Member since September 2012
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Post by The Dad_Ohs on Jun 17, 2013 0:23:08 GMT -5
I think you can get away with the 60/90 with more water to prevent concretion and let it run for a week check it add water if necessary and let it run another week... then check it and add grit to the slurry and let it go another week depending on how it looks... when you finally clean it out dump everything into a 3 inch deep plastic pan and put it outside to evaporate or where it won't freeze... that way everytime you run a course or medium grind you add a 1/4 to 1/2 pound of the dry slurry mix with your grit and you will get a slurry with full grit to help break down the stone faster.... that's what I do with all my course & medium loads and I keep recycling the slurry as it dries it goes into a lg pretzel jar and I add it as I need it to thicken the water mix and form a nice slurry for the rock to tumble in.... Let us know how you make out what ever you do !!!
jus my 2 centavos !!!
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