lancemountain
starting to spend too much on rocks
Member since March 2017
Posts: 214
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Post by lancemountain on May 4, 2017 11:00:39 GMT -5
Hello!
I have a few pieces that came out of polish stage with some cracks and some not so perfect. Can they be put back into an earlier stage along with the same rocks?
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insearchofspace
starting to spend too much on rocks
Member since January 2017
Posts: 108
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Post by insearchofspace on May 4, 2017 11:20:44 GMT -5
Yes!
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lancemountain
starting to spend too much on rocks
Member since March 2017
Posts: 214
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Post by lancemountain on May 4, 2017 11:36:38 GMT -5
thats great news!
Should they go back in at pre polish or second round of softer grit?
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insearchofspace
starting to spend too much on rocks
Member since January 2017
Posts: 108
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Post by insearchofspace on May 4, 2017 11:59:57 GMT -5
If they have deep cracks I'd put them in coarse until they're nice and smooth.
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lancemountain
starting to spend too much on rocks
Member since March 2017
Posts: 214
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Post by lancemountain on May 4, 2017 12:43:34 GMT -5
OK THANK YOU!
One last question-maybe a silly one- will the polish that's on the rocks affect the other raw rocks in the same tumble?
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insearchofspace
starting to spend too much on rocks
Member since January 2017
Posts: 108
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Post by insearchofspace on May 4, 2017 13:36:25 GMT -5
No.
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lancemountain
starting to spend too much on rocks
Member since March 2017
Posts: 214
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Post by lancemountain on May 4, 2017 15:39:25 GMT -5
very helpful thank you again! Much appreciated
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insearchofspace
starting to spend too much on rocks
Member since January 2017
Posts: 108
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Post by insearchofspace on May 4, 2017 19:14:57 GMT -5
No problem.
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grizman
freely admits to licking rocks
Member since July 2011
Posts: 878
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Post by grizman on May 4, 2017 22:04:10 GMT -5
OK THANK YOU! One last question-maybe a silly one- will the polish that's on the rocks affect the other raw rocks in the same tumble? Maybe this will help with some confusion. The "polish" on your rocks is not like a wax or a coating on the rock surface but instead the actual rock's surface has been smoothed by the ascending level of grit fineness to the point where it shines or is "polished". There is nothing to wipe off of the rock after it has been polished. What you see is the "real deal" or actual rock surface. Does this help?
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Post by gmitch067 on May 7, 2017 21:53:44 GMT -5
Interesting info... Thank you! A little confusion here... If a polish fails, is it OK to just run a new polish stage without having to drop back to a previous (courser grit) stage? I did a tumble load (QT66) of mixed jaspers (yellow, brown striped, coconut, and panther), including a week with 1200 grit silicon carbide. Polish was a week in cerium oxide. With the exception of the brown stripe jasper all the other jaspers took a nice glossy shine. The 8 brown striped jasper stones did not take any shine at all. I spent time hand sanding a few pieces (220-600-1000 wet/dry silicon carbide paper) and then, with a dremel tool, retrying to polish using Aluminum Oxide, Cerium Oxide (again), and finally Tin Oxide... No shine (Tin Oxide was the best... but only a satin finish). I did the re-sanding each time thinking it necessary to keep polishes from cross contamination. Hmmm.... looks like I could have saved myself some hand sanding( ).
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Post by deb193redux on May 7, 2017 23:15:29 GMT -5
usually failure means crazing, or some contamination scratching the surface. it needs abrasion at whatever stage/grit needed to get rid of the imperfections.
if the rock is prone to crazing, use more cushion and (if possible) slower rpm
if some cracks hold polish powder, it can't hurt any courser stage.
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Post by gmitch067 on May 8, 2017 1:29:17 GMT -5
Thank you for your reply bed193redux. Out of the 4 types of jasper used, only the brown striped ones did not polish. I could not see any scratches using a 30X loup... so at least the 220 grit stage was successful. I guess to be safe I should return the brown striped jasper back to the 600 grit stage, with more ceramic media, and proceed to a new polish (shifting from using the QT66 to 3A because of the smaller load)
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Post by coloradocliff on May 8, 2017 2:03:44 GMT -5
Are you sure that the stone is a jasper? Could it be a porous, softer rhyolite which wont take a polishing? Some types of stone just wont polish .
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Post by gmitch067 on May 8, 2017 11:37:31 GMT -5
Good possibility Coloradocliff. Unfortunately I do not know the difference and at the mercy of Amazon to tell (I am new to this hobby and I am no longer physically mobile enough to go out in the field). I took a pic of one specimen and will try to copy/past it here... I might have to reread the help pages to get this done...
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metalsmith
Cave Dweller
Member since October 2012
Posts: 1,537
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Post by metalsmith on May 8, 2017 12:07:50 GMT -5
If you have deep pits / cracking / crazing, consider grinding locally just to eradicate those; when you're nearly done, pop them back in the tumbler. This means that the majority of the loss of material is limited to where the imperfections are.
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metalsmith
Cave Dweller
Member since October 2012
Posts: 1,537
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Post by metalsmith on May 8, 2017 12:10:49 GMT -5
Also, note the imperfections (/pitting) on the laguna agate here. Some imperfections don't matter as much as others, but sometimes (in other cases as this is pretty obvious) do let us know that rock is real and not synth.
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ubermenehune
spending too much on rocks
Member since March 2016
Posts: 293
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Post by ubermenehune on May 8, 2017 17:03:17 GMT -5
Some cracks are so deep that no amount of coarse grinding will get rid of them. Or maybe it will take many months, and your material will weather away to a fraction of its original size. Here's a couple other options to consider:
- Sometimes I'll split the material with a chisel on a crack line. I'll end up with two or more smaller pieces, but no deep cracks. - Learn to love deep cracks in your tumbled material.
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Post by gmitch067 on May 8, 2017 21:48:35 GMT -5
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Post by deb193redux on May 9, 2017 13:48:36 GMT -5
hard to tell. if it is rhyolite, it is colorful.
if those small pitts holding white polish keep appearing as you grind, then you will never get rid of them.
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