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Post by joshuamcduffie on Feb 7, 2020 21:39:49 GMT -5
So, I have some neighbors who own a countertop business. Any reason not to get their scraps, bust them up and tumble pieces of granite countertop slabs? I know the granite can take a nice polish, have pretty patterns and colors, and would be free. Any thoughts?
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Post by Pat on Feb 7, 2020 21:58:52 GMT -5
NRG. need you here. Seems reasonable to me.
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Post by hummingbirdstones on Feb 7, 2020 22:32:17 GMT -5
She may have even gotten some Larvikite from her source, too.
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Post by fernwood on Feb 8, 2020 6:00:06 GMT -5
Yes. As with any granite, there can be undercutting, do to the composition of the pieces.
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Benathema
has rocks in the head
God chased me down and made sure I knew He was real June 20, 2022. I've been on a Divine Mission.
Member since November 2019
Posts: 703
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Post by Benathema on Feb 8, 2020 6:10:39 GMT -5
Heh. Dry tumble polish if not satisfied with wet rotary polish. IT WORKED WONDERS FOR ME!
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Post by knave on Feb 8, 2020 7:00:26 GMT -5
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Benathema
has rocks in the head
God chased me down and made sure I knew He was real June 20, 2022. I've been on a Divine Mission.
Member since November 2019
Posts: 703
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Post by Benathema on Feb 8, 2020 7:39:38 GMT -5
No. Okay fine. Granite has the mix of materials, right. The feldspar, quartz, etc. The softer stuff doesn't take nearly the shine as the harder material. Further, from my brief bits of experience, the softer stuff keeps undercutting during the wet rotary polish stage. It takes a ... weird shine ... not so easy to explain other than it leaves more to be desired. Load up a barrel with dry corncob (near abouts 80%), few tablespoons of polish, and a handful (like maybe ten 1.5") rocks in a barrel (QT6), trying to spread them out, and let it run for a week. Go longer if you're not quite satisfied yet. I don't think you'll ever get the glass-like finish like you do with quartz and harder stuff, but you can get a bit more uniform finish across the entire piece, not so splotchy with super shiny quartz and dull feldspar. Okay, took a picture to try to clarify what I mean here. Focus on the black parts of both stones Left went through rotary wet polish. Right also went through rotary wet polish, followed by one week on rotary dry polish in the corncob. That's the difference I'm trying to get across. The one on the right isn't as splotchy. Granted it could probably use some more time, but I'm cool with it.
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NRG
fully equipped rock polisher
Member since February 2018
Posts: 1,630
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Post by NRG on Feb 8, 2020 15:50:05 GMT -5
Granite tumbles poorly. Multiple materials all having different hardnesses.
However, some of it cabs beautifully. And some granite is closely related or actually is Labradorite.
Glue a chunk to a 4x4 and carefully line it up and saw them, it's easily split into two slabs.
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Post by rmf on Feb 8, 2020 16:54:14 GMT -5
As others have said go for it. It is not agate so you may need to experiment. Also, Granite people don't always have granite. they have stuff like larvakite they call granite or some other trade name. See if they have some with garnets in it. Have fun.
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,155
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Post by jamesp on Feb 9, 2020 6:37:23 GMT -5
Re-melted granite(gneiss) does well in the tumbler. Most granite will undercut at the felspar.
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gatorflash1
spending too much on rocks
Active in Delaware Mineralogical Society, Cabchon Grinding and Polishing, 2 Thumlers B's and a UV-18
Member since October 2018
Posts: 375
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Post by gatorflash1 on Feb 10, 2020 8:43:05 GMT -5
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Post by joshuamcduffie on Feb 10, 2020 8:54:53 GMT -5
Thanks for the expertise, I will see what they can provide, and make a tumbling thread. We'll give it a shot.
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