riverrock
fully equipped rock polisher
Member since April 2010
Posts: 1,395
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Post by riverrock on Aug 24, 2015 10:01:20 GMT -5
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rodeodan
starting to spend too much on rocks
Member since January 2010
Posts: 213
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Post by rodeodan on Aug 24, 2015 10:46:52 GMT -5
I feel your pain, other than big pieces, I can't get obsidian to look the same way as other members can. If you come up with a secret recipe, let me know.
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,182
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Post by jamesp on Aug 24, 2015 10:53:55 GMT -5
found that 3 situations minimize bruising riverrock1 smaller pieces 2 snowflake bruises less 3 mahogany bruises less Then comes the filler and/or thickener discussion.
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The Dad_Ohs
fully equipped rock polisher
Take me to your Labradorite!!
Member since September 2012
Posts: 1,860
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Post by The Dad_Ohs on Aug 24, 2015 17:29:00 GMT -5
I've always used lots of filler when tumbling Ob.... any type Ob. And ceramic/plastic filler depending on the step I am on.
When tumbling OB, I usually do the following.... for course grind - lots of filler, 2/3 - 3/4 full barrel, 2 big teaspoons of old tumbler grit (thickener) and water to top of material. When the grit is worn down just add more, do not clean out.
To check the progress of your material, pull out a few pieces and rinse them off to see how they are doing. Add more grit, another spoon or 2 of old grit (thickener), and send it off for another amount of time, for me, a week. when your ready for the next grit, clean everything out really well, check your material and weed out the not ready pieces. set aside whats left and do another batch of course. when they are ready to move on combine with previous batch so you have plenty to fill your barrel.
For the 2nd grind, pretty much same as 1st batch, filler, 2/3 - 3/4 full, water to top of material, grit..... but no thickener for the first round. Once it has run for a week, check it, but don't empty it, rinse off the rocks to check them and put back in barrel if more tumble time is needed. add more grit, as much as you did for the first time with this grit and let it go for another week. Check and repeat as necessary, and follow this for every grit step until completed. the only difference is that when you get to the pre-polish / polish cycles add burnish to the barrels. (and you can use plastic pellets too if you want.)
It's not Gospel, but I have had good luck with this.... I also keep a log book of each batch so if something isn't working I can make note of it and any changes I make to correct the run.
I wish you all best of luck too.
P.S., don't be afraid to take a piece to the wheel/grinder if needed to stop any cracking from spreading as it tumbles. Especially in the first cycle.
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