sharon
off to a rocking start
Member since May 2014
Posts: 2
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Post by sharon on May 21, 2014 7:04:22 GMT -5
I 'm interested in tumbling Lake Superior slices/slabs to use in some stained glass panels. I'm new to tumbling so I was just wondering if it is a different process to do the slabs as opposed to just the original rocks.
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,155
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Post by jamesp on May 21, 2014 7:44:47 GMT -5
Add chips and smalls with them so the slabs do not stick together. A cup or two of sand helps. They will suck together and not get tumbled. The sand helps break the suction. Usually the center of the slabs is last to get polished. Please post panels when done. Welcome to the forum.
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Post by Drummond Island Rocks on May 21, 2014 8:17:18 GMT -5
I agree with James. The main issue will be the slabs sucking up against each other and when that happens the flats will not grind/polish. Are you using strictly rotary tumblers or a combination of rotary and vibrating? I usually run any loads that have small slabs in them with about 1/4 slabs 1/4 filler rocks and 1/2 ceramic filler that is mixed size. Here's some brazilian agate slabs that I had done with that ratio. Chuck
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tkvancil
fully equipped rock polisher
Member since September 2011
Posts: 1,546
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Post by tkvancil on May 21, 2014 9:54:45 GMT -5
I also have in mind doing some slabs, some Lakers and other. Not cut yet but soon. I thought that I'd start them in the vibe and do as many 220 courses as needed to smooth to taste and move on from there. Seeing your results, Chuck, I'll use the same mix of slab, rock, & ceramic.
I have rotary tumbled a few slabs in the past with mixed results. If I ran the slabs longer than 3 weeks the flats would go concave on me. Longer the run deeper the cave. Then the concave area didn't polish as well as one might like. Am thinking this won't be an issue with a vibe.
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gerard
starting to spend too much on rocks
Member since April 2011
Posts: 218
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Post by gerard on May 21, 2014 10:31:26 GMT -5
chuck, Did you preform those beveled edges, or were they rough sawn edges prior to tumble?
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Post by Drummond Island Rocks on May 21, 2014 12:03:04 GMT -5
I did not do any hand grinding on those. The bottom one in the photo is a full mini-slab and the other two may have been decent size cabbing scraps so there is one natural edge and a few cut edges. I rough in the rotary then the rest of the stages are 2 days each in the loto.
Chuck
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