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Post by Jugglerguy on Apr 1, 2015 13:21:07 GMT -5
I just finished a batch of unakite using just my Lortone 33b rotary tumbler. I've never finished a batch in a rotary, only in a vibe. I did my regular rough tumbling, then 220 for ten days and 500 for ten days. I ran them in polish for three weeks. I used ceramic in every stage except 80. It was weird going from 500 straight to polish. The rocks were not shiny at all after 500 and I couldn't believe they polished as well as they did. Normally, after 500 in the Lot-O, the rocks are already very shiny. They turned out fairly well, but they undercut much more than usual. Unakite is prone to undercutting, but if I'm using quality unakite, it doesn't undercut much in the Lot-O. This is my favorite: I don't think this crack would have opened up so much in the Lot-O. I know it was probably only a spall that would have been completely smooth after 80 grit. [/url]
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riverrock
fully equipped rock polisher
Member since April 2010
Posts: 1,395
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Post by riverrock on Apr 1, 2015 18:51:11 GMT -5
Grind the last one i the corner and you have a nice moon .
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Post by Drummond Island Rocks on Apr 1, 2015 20:08:51 GMT -5
That's nice looking material. It has been a long time since I did a full rotary only batch too. Does anyone do a 10 day run in 1000 between 500 and polish or is that only used in the vibe world? I do not remember every going 3 weeks in polish but maybe that helped get a shine on the softer unakite.
Are you going to leave them as is or send them back into 80 for a week or two then run them through the loto to possibly fix them a bit and take comparison shots?
Chuck
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Post by Jugglerguy on Apr 1, 2015 20:18:22 GMT -5
I haven't decided yet, but I'm strongly considering running them again as you suggested. I was wondering about the 1000 stage too, but I did a lot of reading on here, and it seems like that isn't done except for softer stones. I think these qualify as softer, but I wanted to try it without the extra step. It was a fun experiment.
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Post by Drummond Island Rocks on Apr 1, 2015 20:20:34 GMT -5
as long as your having FUN keep at it.
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Post by Jugglerguy on Apr 1, 2015 20:28:13 GMT -5
I will. Weeeeeee!
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,562
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Post by jamesp on Apr 1, 2015 20:48:48 GMT -5
I rotary tumbled for almost 3 years. A good variety. I am thinking the vibe under cuts mohs 5 and 6 stones worse. But unakite does well in my vibe.
The 500 often does not shine in the rotary. But I about always skip 1000 and go straight to polish with no issues. One week in polish on agate is a good polish. But two weeks and it is a real nice polish. But even after 2 weeks the vibe improves the shine on them in a day or two. Vibe gets the polish done so well.
Some folks can do fine with a rotary. I have seen super nice tumbles from a rotary, even softer stones.
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Post by snowmom on Apr 2, 2015 4:51:11 GMT -5
beautiful! Your favorite makes me think of melon rind...
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tkvancil
fully equipped rock polisher
Member since September 2011
Posts: 1,547
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Post by tkvancil on Apr 2, 2015 8:36:01 GMT -5
Have always liked unakite. You have some nice pieces there.
If it were me doing a rotary batch of unakite a 1000 step would be included.
Glad you had fun with it.
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Cob
starting to shine!
Member since February 2015
Posts: 29
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Post by Cob on Apr 4, 2015 10:14:03 GMT -5
Great pictures. What does undercutting look like? Does it put a lip on the edges?
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Post by Jugglerguy on Apr 4, 2015 11:41:39 GMT -5
Undercutting is when softer minerals in the rock wear away more than the harder minerals. The rock ends up not being perfectly smooth, and the undercut areas are usually not polished. It happens a lot with granite for me. I believe that unakite is actually a type of granite. Here's an example of really bad undercutting:
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,562
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Post by jamesp on Apr 4, 2015 13:29:10 GMT -5
I have no solutions, other than thick slurries and lots of fillers. I have about given up on some soft rocks. I am guaranteed a fine finish on agates. It is about worth the extra time to grind harder rocks than babying soft ones. Tumbling is notorious for under cutting. I must say that I have less undercutting in the rotary than the vibe on granite. I think you mentioned it is the other way around for you. i did run some of your unakite in the vibe. the all green had almost no undercutting, but the ones with red did undercut. The green is real nice for tumbling and polishing.
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