Enigman
starting to spend too much on rocks
Member since December 2013
Posts: 163
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Post by Enigman on Dec 11, 2016 13:16:19 GMT -5
Hi all,
I recently tumble polished a load of azurite and malachite mixed stone (ie. both in the same stone). The grit stages were in a Lortone rotary, and the final polish was in a Diamond Pacific MT4 vibe. This routine works well for me for most any stone. However, this stone type seemingly refuses to gain a high polish at all. It simply goes to a satin finish and that's it.
Has anyone found a way, short of hand polishing, to get a vibe to polish this stone to a high shine?
Thanks.
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Post by captbob on Dec 11, 2016 15:58:02 GMT -5
What polish were you using? If Aluminum Oxide, maybe trying a different polish such as Tin Oxide or Cerium Oxide may make a difference. I've had better results using TO rather than AO on softer stones, and CO is supposed to also be good for soft rocks, although I have not tried CO because TO has always done the job for me.
Just a thought.
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Enigman
starting to spend too much on rocks
Member since December 2013
Posts: 163
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Post by Enigman on Dec 11, 2016 16:24:12 GMT -5
Hello,
I have been using aluminum oxide for everything.
I have had the same problem with certain harder stones too. I just ran a batch of sapphire/ruby stone with the same issue. The final finish after 12 days of polish was a gritty matte finish. Earlier I ran some African turquoise (I think it's really a type of jasper) and the finish was mostly matte. That was also a combination stone with tiny dots of black which did gloss up and the rest was matte. I also ran some sanskrit stone with similar results. The yellow streaks polished and the maroon matrix did not.
I guess this is really an issue primarily with hard/soft combination stones. I'll check on the TO or CO.
Thanks.
P.S. - I just checked and tin oxide is almost twice the price of cerium oxide. I would have thought it was the other way around.
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Post by captbob on Dec 11, 2016 16:57:20 GMT -5
P.S. - I just checked and tin oxide is almost twice the price of cerium oxide. I would have thought it was the other way around. Is it? I haven't bought any tin oxide in years. I bought a pound of TO several years ago and still have probably over half left. Don't need to use it on very many rock types, (TO has done well for me with obsidian, chrysocolla and charoite) but have always had good results. Again, I have never used the CO. If you are getting the satin/matte finish on harder rocks as well, maybe it's a tumbling process issue. (?) I don't use vibes, so I'll leave that possibility for others to discuss. Good luck!
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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 Dec 11, 2016 19:22:13 GMT -5
Yep, tin oxide is really expensive, especially the optical grade I use on my cabbing polish pads. Mixed hardness stones are just a booger to do in tumblers. All the softer spots undercut and even the harder spots of many copper mineral mixes are too soft to polish easily beyond a satin finish. I've never had much success except with copper infused quartz, jasper or chalcedony and even those can have areas than undercut badly if you try to tumble them, even if they cab just fine....Mel
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