ataraktos
starting to spend too much on rocks
Member since January 2020
Posts: 140
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Post by ataraktos on Mar 7, 2020 19:03:57 GMT -5
My first finished batch, picture jasper ... they shaped quickly and took a shine well (except like one of them, little weirdo.) Anyway, once they got all nice and shiny, they looked like this ... little pits, absolutely can not feel them but they are pretty uniform over all the rocks (even if the focus/glare makes it look like they don't cover the entire surface in this pictures, they do.) My question is - is this some undercutting type of pitting or did I not spend long enough at one (or more) of the steps? (The stone did shape really fast, especially for a "jasper" - some might have been ready after just a week, but I'd say probably 11-15 days at coarse for most of them.) My first thoughts were to take them all the way back to 120 and lengthen the times at each stage ... then I started to wonder if this could be a widespread undercutting? (And in general, how do you tell?) Thanks for any guidance or advice!
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braat
spending too much on rocks
Member since December 2016
Posts: 350
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Post by braat on Mar 7, 2020 20:23:33 GMT -5
This is just my take on this but when I'm rock hounding and see black on a rock that's mostly quartz, feldspar, jasper etc. I assume it's going to undercut so I reject it. Your rock looks like the pits might be all the way through and re running previous stages may get rid of surface pits but expose more? If you got lots of that rock cut or break one in half and see if the pits are all the way through would be my suggestion...
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ataraktos
starting to spend too much on rocks
Member since January 2020
Posts: 140
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Post by ataraktos on Mar 7, 2020 21:28:05 GMT -5
This is just my take on this but when I'm rock hounding and see black on a rock that's mostly quartz, feldspar, jasper etc. I assume it's going to undercut so I reject it. Your rock looks like the pits might be all the way through and re running previous stages may get rid of surface pits but expose more? If you got lots of that rock cut or break one in half and see if the pits are all the way through would be my suggestion... You assume the whole rock will undercut or just the black bits? I don't have a way to cut one but I don't feel like the pits go all the way through. Macro picture/lighting might make them worse than they are. What they remind me of is like a varnish coat applied as polish and it's flaking off. I could try to break one. Maybe. =)
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braat
spending too much on rocks
Member since December 2016
Posts: 350
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Post by braat on Mar 7, 2020 21:57:38 GMT -5
Just the black bits...just a general statement from my limited experience, Your second photo looks like there's definite pitting to me?? You can always tumble the two halves if you break one...it's all guess work till you know what's inside in my opinion... maybe others will have better answers/suggestions....
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Post by aDave on Mar 7, 2020 23:23:21 GMT -5
Your rock is well shaped and it would be the type of material I'd move on through all stages after coarse.
Problem is, as you noted, you have some pitting at the end of the day. In the end, that's not unusual, since different parts of the rock may "react" differently when being tumbled.
If your rock consists of different minerals, it may undercut a bit, and there's no getting around that.
All I can say is the more you tumble a particular type of material, you'll learn what you can get out of it. Not all rocks will finish smoothly, and this may be the case with what you have recently rolled. It will come to a point where you'll be able to identify what you can get out of a rock, and you'll move it along as you see fit. For example, there is one type of rock that I love tumbling, but I know it will pit through the stages. I've just learned to live with it, and I accept pitting with this particular rock. It's just the nature of the beast.
Hope this helps a bit.
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gatorflash1
spending too much on rocks
Active in Delaware Mineralogical Society, Cabchon Grinding and Polishing, 2 Thumlers B's and a UV-18
Member since October 2018
Posts: 375
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Post by gatorflash1 on Mar 8, 2020 7:48:44 GMT -5
I just live with it. There are so many little dots it is not worth trying to fix them. Find a better rock next time. Stuff happens!
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old hound
starting to shine!
Member since August 2018
Posts: 36
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Post by old hound on Mar 8, 2020 22:11:41 GMT -5
Had the same problem with some picture stone,on page three not running stage two long enough by JamesP explained a lot I rerun starting with 500 ao then 1000 ao then polish much better finish.
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ataraktos
starting to spend too much on rocks
Member since January 2020
Posts: 140
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Post by ataraktos on Mar 10, 2020 13:02:46 GMT -5
Had the same problem with some picture stone,on page three not running stage two long enough by JamesP explained a lot I rerun starting with 500 ao then 1000 ao then polish much better finish. Thanks! I have started them over, I figure I can compare and learn more from the same stone, even if it's no better (lol or worse. Always that possiblity!) I'm also having a few pieces get "stuck" somewhere in the vibe. Overall movement always seems pretty good but so far, two pieces have gotten a little "chewed up" (little circular bullseye marks, something I don't you'd ever see in a rotary), so trying to figure that out too. I've added more (similar hardness) rough that was ready for 120 too, perhaps I had too much media, not enough rough.
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Post by RocksInNJ on Mar 10, 2020 20:45:31 GMT -5
Had the same problem with some picture stone,on page three not running stage two long enough by JamesP explained a lot I rerun starting with 500 ao then 1000 ao then polish much better finish. Thanks! I have started them over, I figure I can compare and learn more from the same stone, even if it's no better (lol or worse. Always that possiblity!) I'm also having a few pieces get "stuck" somewhere in the vibe. Overall movement always seems pretty good but so far, two pieces have gotten a little "chewed up" (little circular bullseye marks, something I don't you'd ever see in a rotary), so trying to figure that out too. I've added more (similar hardness) rough that was ready for 120 too, perhaps I had too much media, not enough rough. You can also add a some sugar in the vibe to thicken the slurry and slow the action down some to prevent the bruising. I had to do this with my UV-10, because the cyclonic action was so damn fast.
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ataraktos
starting to spend too much on rocks
Member since January 2020
Posts: 140
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Post by ataraktos on Mar 11, 2020 9:01:36 GMT -5
Thanks! I have started them over, I figure I can compare and learn more from the same stone, even if it's no better (lol or worse. Always that possiblity!) I'm also having a few pieces get "stuck" somewhere in the vibe. Overall movement always seems pretty good but so far, two pieces have gotten a little "chewed up" (little circular bullseye marks, something I don't you'd ever see in a rotary), so trying to figure that out too. I've added more (similar hardness) rough that was ready for 120 too, perhaps I had too much media, not enough rough. You can also add a some sugar in the vibe to thicken the slurry and slow the action down some to prevent the bruising. I had to do this with my UV-10, because the cyclonic ac tion was so damn fast. thanks! I've read about that but trying to avoid, it sounds sticky and messy? But, if I have to... I also have some psylium fiber. With more rough, it didn't happen last run. I think in spots, it just got a little choked on media but with more rough, another big rock comes along sooner to break things up.
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,561
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Post by jamesp on Mar 11, 2020 9:24:05 GMT -5
Had the same problem with some picture stone,on page three not running stage two long enough by JamesP explained a lot I rerun starting with 500 ao then 1000 ao then polish much better finish. Thanks! I have started them over, I figure I can compare and learn more from the same stone, even if it's no better (lol or worse. Always that possiblity!) I'm also having a few pieces get "stuck" somewhere in the vibe. Overall movement always seems pretty good but so far, two pieces have gotten a little "chewed up" (little circular bullseye marks, something I don't you'd ever see in a rotary), so trying to figure that out too. I've added more (similar hardness) rough that was ready for 120 too, perhaps I had too much media, not enough rough. You can toss a few stones that you had already polished in at step 3 and/or step 4(polish) just to see if the new rocks are getting the same treatment as the old rocks did. It can be informative to re-run a couple of test rocks especially if you arrive at a better polish. Unpolishing and then re-polishing so to speak. Or toss certain types of stones in with the batch to see how they compared to the last time such rock was tumbled. And pick a type of rock to use as a 'test' rock for future tumbled batches. You may be surprised to find you can skip a step or shorten steps. A couple of obsidians can be run with the batch just to see how they fare. Or a couple of glass stirring rods say cut to 4 to 5 inches long just to see if the batch is running gentle. Is it easier to run step 1/SiC 60 for an extra week to break it down for 500 step ? Or is it better to do a clean out and run a 220 step before the 500 step ? Many are finding the 7 to 10 day 220 step is redundant. I sure have if I let step 1 run 7 to 10 days to break the SiC 60(or even SiC 30 for that matter) down well.
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ataraktos
starting to spend too much on rocks
Member since January 2020
Posts: 140
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Post by ataraktos on Mar 11, 2020 19:50:50 GMT -5
You can toss a few stones that you had already polished in at step 3 and/or step 4(polish) just to see if the new rocks are getting the same treatment as the old rocks did. It can be informative to re-run a couple of test rocks especially if you arrive at a better polish. Unpolishing and then re-polishing so to speak. Or toss certain types of stones in with the batch to see how they compared to the last time such rock was tumbled. And pick a type of rock to use as a 'test' rock for future tumbled batches. You may be surprised to find you can skip a step or shorten steps. A couple of obsidians can be run with the batch just to see how they fare. Or a couple of glass stirring rods say cut to 4 to 5 inches long just to see if the batch is running gentle. Is it easier to run step 1/SiC 60 for an extra week to break it down for 500 step ? Or is it better to do a clean out and run a 220 step before the 500 step ? Many are finding the 7 to 10 day 220 step is redundant. I sure have if I let step 1 run 7 to 10 days to break the SiC 60(or even SiC 30 for that matter) down well. haha, i started them all over. i'll know if the polish is better! =) as i'm been looking at them closer, there's one specific-brown-colored band that is pitty. and the polish, all over, the first time was 'flakey' for lack of a better word. didn't show up well in the pictures. hopefully, it'll be a little more even this time and then, getting the polish out of the pits will be ... difficult. in trying to fill out the barrel with more rough, i've added some jasper, pet wood, and just a few little pieces of amethyst and quartz. so far, they are faring ok (well the quartz is new tonight). but i like the stirring rod idea! are they a standard size/diameter? i have, oddly enough, microscope slides and i've seen someone on here mention those, iirc - i might've been you! should i expect a slide not to break in a "gentle enough" tumble? i can totally get glass rods though, if i know what size to get. i have one piece of obsidian. it's almost as big as the lot-o barrel. i wasn't expecting that, gotta break it up at some point. thanks!
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,561
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Post by jamesp on Mar 11, 2020 20:17:01 GMT -5
A longer say 4 - 5 inch shard of window glass will also do the trick. Microscope slides. 3/16 to 1/4 inch glass stirs 4 - 5 inches long.. Any should work well ataraktos.
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ataraktos
starting to spend too much on rocks
Member since January 2020
Posts: 140
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Post by ataraktos on Mar 12, 2020 10:13:33 GMT -5
A longer say 4 - 5 inch shard of window glass will also do the trick. Microscope slides. 3/16 to 1/4 inch glass stirs 4 - 5 inches long.. Any should work well ataraktos. Thank you so much - I'll toss in a microscope slide and see what happens!
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,561
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Post by jamesp on Mar 12, 2020 10:22:21 GMT -5
A longer say 4 - 5 inch shard of window glass will also do the trick. Microscope slides. 3/16 to 1/4 inch glass stirs 4 - 5 inches long.. Any should work well ataraktos. Thank you so much - I'll toss in a microscope slide and see what happens! A microscope slide in most cases is about as delicate is all listed ataraktos. Does not hurt a thing to run test stuff like that. If you have any clay in your back yard you might try some of it in the rotary for thickener.
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ataraktos
starting to spend too much on rocks
Member since January 2020
Posts: 140
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Post by ataraktos on Mar 13, 2020 10:23:04 GMT -5
A microscope slide in most cases is about as delicate is all listed @akaraktos. Does not hurt a thing to run test stuff like that. If you have any clay in your back yard you might try some of it in the rotary for thickener. You know, I tried all-clay cat liter once, that I had on hand for something else ... only time (so far) that i've had a batch "frost" - it was fire quartz, i think. at the time, i thought it might have been contaminated with sand? (I mean, in coarse, i guess frosting really doesn't matter?)
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