aunuts
fully equipped rock polisher
Some days are gold, some are rocks. Either is cool.
Member since March 2006
Posts: 1,110
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Post by aunuts on Feb 11, 2011 20:33:46 GMT -5
I was given some Coober Pedy potch at the PowWow in Quartzsite. The man that gave it to me asked me to tumble some of the opal. Some of this opal has been crazed because it was sitting out in the weather. I have a rotary tumbler, not a vibrating tumbler. Is it possible to tumble this stuff? What grit should I use if I can do it? I'd like to try it so I can tell him what the results were. Can anyone give me some pointers?
Thanks much, Jo
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stefan
Cave Dweller
Member since January 2005
Posts: 14,095
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Post by stefan on Feb 11, 2011 20:59:01 GMT -5
I've tumbled opal before. Actually pretty easy if the matrix is good and stable. If the opal is crazed real bad it may fall apart on you. You can stabelizing it (opticon, or if your cheap like me crazy glue, but beware it may yellow). If I remember I tumbled my opal with glass and obsidian in my rotaries. If your afraid to try it, send it to me and I'll try to do it for you
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aunuts
fully equipped rock polisher
Some days are gold, some are rocks. Either is cool.
Member since March 2006
Posts: 1,110
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Post by aunuts on Feb 11, 2011 22:49:26 GMT -5
Fantastic! I'll give it a try. Obviously, I'm not using anything with any flash in it. A lot of it is crazed, but pretty stable anyway. I'll superglue it. What grit do you use to start? Oh yeah, did you tumble it with water? Dry? What? Thanks so much. Jo
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Post by susand24224 on Feb 11, 2011 23:53:17 GMT -5
Hi, Jo, I've tumbled common opal and jelly opal often, and various others on occasion. I start with 60/90 (or right now 80 since it was cheaper) and add ceramics and a little soap. In the soap dept. I've used Ivory snow soap shavings, borax and Dreft all of them have worked. The soap does seem to slow down the action a bit, so I do cycles of ten days rather than seven.
If the opal seems fragile, or turns out to be "chipping prone," I would add up to 50% ceramic shapes. I rarely (as in once a year) use plastic pellets, but they may work just as well.
Oh, yes, I also start the water level a little lower than usual since the soap foams it up and also the opal initially wears down quickly. I use 500 and 1000, and polish with AO from the Rockshed.
Susan
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aunuts
fully equipped rock polisher
Some days are gold, some are rocks. Either is cool.
Member since March 2006
Posts: 1,110
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Post by aunuts on Feb 12, 2011 0:25:15 GMT -5
Thanks so much for the help. I'll give it a try with your directions. I'm anxious to see how it turns out. jo
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stefan
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Member since January 2005
Posts: 14,095
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Post by stefan on Feb 12, 2011 7:47:26 GMT -5
I too start at 60/90. I always add a little borax to all my loads. I checked my records and I tumbled it with glass and obsidian. I always run 2 week course cycles. I follwed up with a 2 week 120/220. Then a 2 week 500, 2 week tripoli, 2 week tin oxide. Turned out nice
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Post by rockrookie on Feb 12, 2011 8:32:01 GMT -5
never done Coober Pedy . i have done Koroit with good success . once the loose matrix goes to mud . the hard matrix takes a amazing shine . --paul
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chassroc
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Rocks are abundant when you have rocktumblinghobby pals
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Post by chassroc on Feb 12, 2011 9:51:38 GMT -5
i have never tumbled opal but even if there is no flash, i would be very careful with the 60/90. either check it evry 1/2 day or start more cautiously with 220 and check daily until you can get a feel for what you are doing. when i cab cooper pedy i do not use a course grit wheel at all. it is not as hard as agate, jasper, and pet wood charlie
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aunuts
fully equipped rock polisher
Some days are gold, some are rocks. Either is cool.
Member since March 2006
Posts: 1,110
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Post by aunuts on Feb 12, 2011 13:53:26 GMT -5
You guys are all the best. Thanks so much! jo
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MikeS
fully equipped rock polisher
Member since January 2009
Posts: 1,081
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Post by MikeS on Feb 13, 2011 11:47:35 GMT -5
I've tumbled lots of common opal and wood that is near 100% opal...I do all the stages except for the final polish in my rotory tumbler, (the rotory isn't nearly as agressive in the coarse stages so I don't lose as much) with plenty of plastic tile spacers to cushion them, and then do the final in a vibe, again with plenty of tile spacers to cushion them. They usually turn out pretty nice.
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