yetiabitibi
starting to shine!
Member since February 2016
Posts: 25
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Post by yetiabitibi on Mar 25, 2017 10:28:33 GMT -5
We're looking into buying a tumbler soon and while we have plenty of hard (ish) stuff like agates, we've also got a lot of softer material.
Specifically, we've got some nice serpentinite rocks (hardness 4-5) and lots of barite (hard 2.5 - 3) with really nice color.
I'm especially worried about the barite because of the mix of softness and high density. Will it just tear itself apart?
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tkvancil
fully equipped rock polisher
Member since September 2011
Posts: 1,546
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Post by tkvancil on Mar 25, 2017 15:49:46 GMT -5
Some rocks in the 4 to 5 range can be tumbled successfully. Most will require special procedures. The barite would most likely grind into nothing in quick order.
Start out with your harder stones. much easier to get a good shine. Once you have a good handle on how to do agates and such move on to the more challenging softer stones.
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SirRoxalot
freely admits to licking rocks
Member since October 2003
Posts: 790
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Post by SirRoxalot on Apr 8, 2017 11:30:04 GMT -5
The soft stuff will be nicely rounded and beautifully smoothed in a gratifyingly short time.
However, you can burn an awful lot of time trying to figure out how to polish them, and that's barrel time that could be better used on things that are happy to take a polish. I have 80 pounds of rock rolling at any given time, and yet seldom do I feel happy about wasting any capacity on experimenting with the soft nuisance rocks... so many weeks are consumed getting agate and jasper coarse-ground, months and years fly by.
I believe that the beautiful, apparently tumble-polished soft materials like fluorite, malachite, calcite, kyanite, etc. that we see at the shows are in fact polished by hand in China, where they're happy to work for a buck a day.
If you feel in the mood to experiment, have at it, it can be a lot of fun, but in my experience, I wouldn't get your hopes up.
If you find the secret to polishing the low-Moh's goodies that are so darn beautiful, do let us know, maybe a fresh set of eyes can solve the problems they present.
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AveryLindgren
starting to shine!
Member since April 2017
Posts: 40
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Post by AveryLindgren on Apr 10, 2017 5:26:00 GMT -5
A very God tumbler in my option would be to get the thunders tumbler model b its a 15 pound tumbler,great tumbler mine has lasted me over a decade. It will do the job.but your problem with the softer stones,I think it would work depending what you use for grit and other materials you use.
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lookatthat
Cave Dweller
Whatever there is to be found.
Member since May 2017
Posts: 1,360
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Post by lookatthat on May 15, 2017 10:31:47 GMT -5
I have seen some very tough serpentine that I think would take at least a fair polish.
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Post by coloradocliff on May 15, 2017 11:29:53 GMT -5
A very God tumbler in my option would be to get the thunders tumbler model b its a 15 pound tumbler,great tumbler mine has lasted me over a decade. It will do the job.but your problem with the softer stones,I think it would work depending what you use for grit and other materials you use. Plus 1 on the b model tumbler. Also consider a vibe lot o for the quick finish and polish. The barrel shapes your stuff and vibes really shines it quick. Nows the weather in Michigan this am Avery / Cloudy/ Warm and sunny in the Colorado Rockies.
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lookatthat
Cave Dweller
Whatever there is to be found.
Member since May 2017
Posts: 1,360
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Post by lookatthat on May 15, 2017 13:50:22 GMT -5
I have a similar question regarding "soft" stone. I have a few pounds of beautiful stromatolite chunks from Herkimer, NY. Has anybody successfully tumbled this material?
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Post by krazydiamond on May 15, 2017 16:18:01 GMT -5
i wouldn't think stromatolite would tumble well at all.
KD
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Post by rockpickerforever on May 15, 2017 17:30:31 GMT -5
It depends on how "soft" your stromatolite is. The stromatolite found in Southern California is pretty well silicified. It takes a great polish, and has some interesting patterns. I have tumbled some in the past, also have some in the tumbler right now.
Just getting started. Was tumbled with rocks of varying hardness, up to hard-ass GA coral.
This one broke into 3 pieces before finishing . Too much action.
Finished. Stromatolite in center of pic.
I like them, but to each his own. I am an old newbie at this, just started tumbling again after a 40+ years hiatus. Got a good deal on 50# 30 grit SiC from Kingsley North. That should keep me busy for a while.
I am an advocate of the jamesp "add a cup of 30 grit every few days" plan, using rotary tumblers (Lortone QT66 and 15 lb Scott/Murray). When rocks are shaped to my liking, I let the grit wear down until it is very fine. Move rocks to Gy-Roc A vibe using 220, let it break down. Then use Cerium Oxide for polish. Have run two batches this way. Works for me.
Good luck with your new tumbler, and your next batch.
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lookatthat
Cave Dweller
Whatever there is to be found.
Member since May 2017
Posts: 1,360
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Post by lookatthat on May 15, 2017 20:04:51 GMT -5
Cool, rockpicker! I will have to ask you for details on the stromatilites once I actually get to that (of course i have to find where i put them...) Sorry to highjack the thread.
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frostedoddity
off to a rocking start
Hello from Tampa Bay, Florida!
Member since May 2017
Posts: 8
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Post by frostedoddity on Jun 8, 2017 17:19:10 GMT -5
As has been mentioned, in my experience harder rocks are better to learn with because there's more room for error without damaging them or wearing them away. When experimenting with softer rocks I'd use a medium or fine grit depending on the softness, and check on the rocks in a few hours the first couple times to monitor progress.
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