danb
starting to spend too much on rocks
Member since March 2011
Posts: 107
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Post by danb on Mar 12, 2013 1:04:02 GMT -5
I have a ton of small agates with little pits in them that just grow when I tumble them in my rotary tumbler. I just ordered a lot-o today, and I am hoping that they might come out better. Am I dreaming? Is there any way to prevent this? Any suggestions? They are beautiful agates, but I am losing so much size...
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Mattatya
spending too much on rocks
Member since June 2012
Posts: 452
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Post by Mattatya on Mar 12, 2013 2:43:26 GMT -5
Pitted agates that you can't just pass over to the rock garden. I have lots of those too. I haven't tried this yet but there are lots of threads about filling pits when polishing cabs. Should work for tumbling rock as well. There are lots of glues and epoxies, folks mention using everything from cheap simple crazy glue (will turn color over time) to expensive 2 part epoxies that take a week under a lamp to cure. I'm not much help as I have little experience with filling pits and fractures but here is a recent thread discussion on the subject.
forum.rocktumblinghobby.com/index.cgi?action=display&board=tips&thread=58294&page=1Hope that helps, Matt
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Sabre52
Cave Dweller
Me and my gal, Rosie
Member since August 2005
Posts: 20,487
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Post by Sabre52 on Mar 12, 2013 9:16:08 GMT -5
I've messed with some pitted lakers I wanted to save. Tried them in the vibe tumbler after filling a few pits with glue and the fine grind scooped the glue right out of the pits. I came to the conclusion that heavily pitted specimens are just not suited for the tumbler and are a waste of time. I now just chuck'em onto my rock pathways.....Mel
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,561
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Post by jamesp on Mar 12, 2013 9:36:33 GMT -5
These always polish well,and dozens have grit left over from way back in the coarse grind stage.Atleast a hundred grit particles per load.The little geodes are throughout this material.You cannot grind them out... This one from the same batch w/pretty nice polish Most of the grit particles get polished with the rock like this patricle did.It is flush with the surface of the rock. Mario told me to use a needle to remove the grit-works great.
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Post by Hard Rock Cafe on Mar 12, 2013 10:12:07 GMT -5
Yeah, pitted rough sometimes just exposes more pits as you grind. Either live with the pits or move on to solid material.
Lakers usually just have surface pits, but you lose a lot of rock trying to grind them away.
Chuck
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,561
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Post by jamesp on Mar 12, 2013 11:48:49 GMT -5
Yep,that's the way it is Chuck. I am amazed at how well agates polish even though many have grit in the pockets thru all 4 steps of the tumble process....
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tkvancil
fully equipped rock polisher
Member since September 2011
Posts: 1,547
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Post by tkvancil on Mar 12, 2013 12:28:31 GMT -5
I've tried super glue to fill pits and cracks in my rotarys. It either grinds out or lifts off after spending all that time in water and grit.
You can send pitted or cracked rocks to polish. I do it all the time. Just make sure that they are clean. Myself, I tumble wash them in a combination of shaved ivory soap and borax for 24 hours before I polish them.
Jamesp's pics are an excellent illustration of how flawed stones can be well polished.
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Minnesota Daniel
freely admits to licking rocks
A COUPLE LAKERS
Member since August 2011
Posts: 891
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Post by Minnesota Daniel on Mar 12, 2013 21:43:29 GMT -5
Assuming the agate is worth the effort, I grind the individual pits out using a Dremel Tool with a diamond bur. I do it just enough to where the pit is entirely in hard agate and won't keep growing, and clean enough so that the grit and polish wash out easily. The pits still won't polish of course, but they won't keep causing problems, and you won't grind away the rest of the agate trying to get the pits out in the tumbler.
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custommike
starting to shine!
Member since November 2012
Posts: 42
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Post by custommike on Mar 18, 2013 14:42:16 GMT -5
Glad I read this thread I have been grinding away at some carnelian for several weeks now trying in vain to get the pits out...
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