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Post by Jugglerguy on Jan 29, 2012 21:01:58 GMT -5
I just got done ordering a Lot-O-Tumbler from the Rock Shed. I have some granite tumbling in my rotary tumbler right now in 120/220 grit. I was told by Shermlock that sometimes granite undercuts in later stages. When I ordered something from the Rock Shed about a month ago (I'm making a habit of ordering stuff), Shawn suggested using 1000 grit for granite because it's softer. So I ordered some. I'm wondering if I should finish the granite in the Lot-O or in the rotary. Should the 1000 grit stage be done whether I do it in the vibe or the rotary? I was also wondering if mixing rocks of different hardness matters in a vibratory tumbler as it does in a rotary tumbler. My other 3 lb. barrel has quartz I picked up off the beach. Should I keep that separate from the granite or could I mix it? Thanks, Rob Attachments:
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jspencer
freely admits to licking rocks
Member since March 2011
Posts: 929
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Post by jspencer on Jan 29, 2012 23:58:44 GMT -5
I`d say it matters more in a vibe with differing hardness. The quartz will undercut the granite. And I would use the 1000 either with rotary or vibe. I have a 400-1000 sc I run in vibe for 3 days before polish. Or a run of 600 and then prepolish. I find quartz can really do some damage in latter stages. I try and do quartz alone or with some aventurine which is pretty plentiful in a variety of colors here. Some quartz even seems to tear up other quartz rocks too.
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Post by connrock on Jan 30, 2012 11:14:28 GMT -5
Granite will undercut a bit no matter which tumbler you use and it will never polish up like quartz. You shouldn't mix different hardness rocks in any type of tumbler. I've never finished granite in a rotary so I don't know which does a better job,,,rotary or vibe? I do tend to favor the vibe only because of the amount of 1000 grit used in it,,,,1/2 teaspoon as opposed to a lot more in a rotary.
connrock
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Post by susand24224 on Jan 30, 2012 15:22:23 GMT -5
I've tumbled granite in both a rotary and a vibe and don't really see a difference. Some types undercut more than others, but they all seem to undercut at least a little.
I use 1000 in both rotary and vibe with granite, but I use 1000 with everything in the vibe.
Incidentally, you get your worst undercutting in 1000 and polish.
Susan
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Post by Jugglerguy on Jan 30, 2012 16:04:17 GMT -5
Thanks for the advice everyone. I guess I'll use the Lot-O for the granite and save some grit. That's one of the biggest reasons I bought it. Is it common practice to use 1000 grit in vibes all the time, or is this something you do differently, Susan? Also, is there any reason to ever finish something in the rotary, or should I just use it for rough tumbling?
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Post by susand24224 on Jan 31, 2012 19:24:17 GMT -5
I'm really not any kind of expert on vibes, as you will see in the rest of my answers. I always use 1000 grit in the vibe because that is what Connrock told me to do. I have read that some stones don't do as well in vibes, but have not yet had that experience. I have also read that some don't do well in rotaries, but I just recently got a vibe and have had rotaries for years and tumbled multitudes of stones without a problem. 1000 grit is always better in a rotary (and probably a vibe as well) for softer stones. I don't think it really makes a difference on, for example, Mohs 7 stones. Susan
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Post by Jugglerguy on Feb 1, 2012 13:56:55 GMT -5
Thanks Susan. I'm learning a lot here. Now it's just going to take lots of time to gain experience.
Rob
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Post by rockpickerforever on Jun 16, 2023 21:20:47 GMT -5
This is an 11+ year old post. I'd like to think that most of us have become more edumacated about rocks and Tumbling. Including Rob!
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stefan
Cave Dweller
Member since January 2005
Posts: 14,095
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Post by stefan on Jun 28, 2023 8:35:05 GMT -5
LOL I wonder if Rob ever got that granite to tumble? If anyone is interested granite will tumble ok. It undercuts because the mica or "black flecks" are too soft. The fewer black flecks the better it turns out. This is why Unakite tumbles so well because there is very little mica in it. We have a lot of granite around here and it can be a great tumble.
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