mikeinsjc
spending too much on rocks
Member since June 2010
Posts: 329
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Post by mikeinsjc on Nov 12, 2014 9:43:47 GMT -5
Do either corn cob or walnut shells have a function in tumbling stones? If so, when are they used?
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,159
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Post by jamesp on Nov 12, 2014 9:57:41 GMT -5
Some rocks are sensitive to surface chips and frosting. Such materials are used for padding to reduce such damage. Plastics may be more reliable and less apt to breakdown.
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Deleted
Deleted Member
Member since January 1970
Posts: 0
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Post by Deleted on Nov 12, 2014 15:31:26 GMT -5
hmmm.... walnut shells are cheap.
The question is---------- do they sink or float?
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Deleted
Deleted Member
Member since January 1970
Posts: 0
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Post by Deleted on Nov 12, 2014 15:33:38 GMT -5
This website says SG is 1.2-1.4 so it ashould be a sinker. Sounds like a great cushion!
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Post by Jugglerguy on Nov 12, 2014 17:14:36 GMT -5
The Rock Shed has this recipe for fluorite that uses corn cob as a dry step. I haven't tried it though.
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Post by Drummond Island Rocks on Nov 12, 2014 18:13:04 GMT -5
The Rock Shed has this recipe for fluorite that uses corn cob as a dry step. I haven't tried it though. I bought the corn cob from rockshed and followed the instructions but my fluorite still turned out horrible. I only tried it one time and I suppose it could have been low quality material. I have never tried it on any other stones. Jugglerguy I wonder how our local petoskey stones or kona dolomite would do with a dry polishing compound? Chuck
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Post by Jugglerguy on Nov 12, 2014 18:50:01 GMT -5
Chuck, I bought some corn cob to try with Kona, but it goes bad in 500 grit every time I try it. The Rock Shed's instructions start after 500, so I never even opened the packages. I've never tried Petoskey stone in a tumbler past the rough grind, but I'd like to play around with it sometime. I have some low quality stuff I don't mind ruining. Do you have any suggestions for how I should go about it?
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Post by Drummond Island Rocks on Nov 12, 2014 18:56:09 GMT -5
Do you have any suggestions for how I should go about it? I was going to ask you the same thing, lol Chuck
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Post by Jugglerguy on Nov 12, 2014 19:03:24 GMT -5
If I ever get around to trying it, I'll let you know what to do or what not to do.
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stonemaster499
noticing nice landscape pebbles
Member since July 2014
Posts: 97
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Post by stonemaster499 on Nov 12, 2014 22:14:14 GMT -5
Corn cob and Walnut shells are the most common DRY polish media in the reloading and deburring industries. Many in that area use a 50:50 blend between the two, with more people getting a better polish with corn cob. use the same amount of polish you would for wet polish.
For soft stones, I have had no luck yet polishing wet. Let me rephrase - dry polish does a better job than wet polish for soft stones. Using fixed-speed vibratories. Many of the experienced tumblers here claim you cannot polish certain stones. I have succeed with 2 of those stones on the first attempt each using dry polish. Benefits: Easy to store No mess reuse it upto 16x easily. I simply pour into a 1 mil polybag. seal, date and label. mark on the bag each time i use it. Best part is you dont have to "clean the polish off your rocks". They come out more or less clean.
Putting it into a wet slurry? Why? what a mess. SAFETY WARNING: USE A MASK TO PROTECT AGAINST FINE DUST WHEN DOING DRY POLISH. I put a fresh shopping bag (through the middle bolt) underneath my polish bowl to prevent dust from getting down into the motor. **lube your motor at least every 6 months.
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Post by snowmom on Nov 13, 2014 5:59:24 GMT -5
stonemaster- would love to see some pictures of your dry polished rocks. good info- good safety warning! thanks!
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Post by Jugglerguy on Nov 13, 2014 13:48:11 GMT -5
Stone master, you have my attention. I have a couple questions.
Which two stones did you successfully polish using a dry technique that you couldn't polish wet?
Do you only use corncob for dry polishing, or can you use it for stages before polish? In other words, could I use 500 or 1000 grit with corncob? The Kona dolomite I tried to tumble always went bad well before I was ready to polish it. By the end of the first day in 500 grit, it already looked bad.
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Deleted
Deleted Member
Member since January 1970
Posts: 0
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Post by Deleted on Nov 13, 2014 13:55:10 GMT -5
Putting it into a wet slurry? Why? what a mess. I would have to agree corn cobs would become a mess. But walnut shells? Those are harder than the tree's wood. Shouldn't make a mess. Never tried tho'.
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stonemaster499
noticing nice landscape pebbles
Member since July 2014
Posts: 97
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Post by stonemaster499 on Nov 13, 2014 17:02:42 GMT -5
snowmom- shotgunner- Not a mess at all. The mess is with a wet slurry. Jugglerguy- I use it only for polish. I bought my corn cob from a reloading media supplier and my grit size seems too fine (I would prefer 6/20) however, with my 1 failed attempt at copal - I got to the end with a poor swirling polish; like magnified fingerprints, and a piece of small apatite contaminant in the polish didn't help either. I lost control. There was some forwards and backwards (1000 dry, 500 dry, 120 wet, 500 dry, 1000 dry, dry polish) I dropped to 500 dry, 1000 dry before polish dry. I needed to get to 120/220 wet for any real shaping to remove the rind. It worked fine....but prefer wet till polish. (soft / delicate stones). I just couldn't control the swirl scratches and final polish. Copal is like snowboarding or surfing, as You wont get it the first time.. (i will figure copal out likely in my 3-4th attempt whenever I have time...) Of the 2 stones I did, experienced members have struggled with over the years both polished up better than my lapidary employees do by hand. The 2 stones I was successful with 1st attempt were Labradorite Apatite
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Post by Jugglerguy on Nov 13, 2014 22:46:53 GMT -5
So you have tried 500 and 1000, which are not polish, but without any luck. I'm going to have to try this with my Kona dolomite. I can't mess it up any worse than I did before, so there's nothing to lose.
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stonemaster499
noticing nice landscape pebbles
Member since July 2014
Posts: 97
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Post by stonemaster499 on Nov 14, 2014 16:01:43 GMT -5
5F SiC + corn cob dry media, and 1000 SiC corn cob dry both worked fine for me. My copal didn't turn out so well in the end. I'm not sure where the issue was. I prefer 500 and 1000 wet and using thickeners and cushioning. Diamond pacific for the (last 15 years or so) have been selling a "vibra-dry" 25,000 and 50,000 to replace wet polish stages. They advertise that it does a better job and no mess. Speaking to Don at DP, he told me their product uses diamond paste with the dry media (presumably corncob). For polish- Al Ox. polish + dry corn cob media worked great, for me, "for soft/and or delicate stones".
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