Fossilman
Cave Dweller 
Member since January 2009
Posts: 20,723 
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Post by Fossilman on Nov 22, 2023 13:17:09 GMT -5
With obsidian you have to have a rotary tumbler and finish off with a vibe tumbler..
A lot of grinding inperfections too.
Lot of work, but I have seen some great results with my buddy's obsidian..
Patience and practice.... I'm not there yet either ..😎😂🤔
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Post by HankRocks on Nov 22, 2023 16:19:50 GMT -5
I have used previously polished small saw scraps and pea gravel for cushioning to successfully tumble polish obsidian/Apache Tears. Being previously polished they provide smoother contact points for the obsidian. Started with about 30% fill in the Model B rotary to run these thru the stages to polish. As the target rocks shrank during each stage I added more fill to make up the lost volume which resulted in about 40 to 45% fill. The picture below was from one batch, of 3 different frost-prone materials, Tigereye, Ark Quartz Crystal and Apache Tears. I do add a good bit of saved slurry to each stage including extra saved polish to help cushion. Just note that there are no large pieces in the run.  IMG_1811 by Findrocks, on Flickr |
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geoff59
spending too much on rocks
Member since October 2022
Posts: 288
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Post by geoff59 on Nov 28, 2023 4:12:12 GMT -5
You don’t need a vibe. This is the last batch I did, just out of it’s hot bath a few months back, in a 3lb rotary drum. Black, rainbow, and snowflake, with a few Apache tears.  |
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dillonf
fully equipped rock polisher
Hounding and tumbling
Member since February 2022
Posts: 1,622
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Post by dillonf on Nov 28, 2023 7:35:36 GMT -5
I have used previously polished small saw scraps and pea gravel for cushioning to successfully tumble polish obsidian/Apache Tears. Being previously polished they provide smoother contact points for the obsidian. Started with about 30% fill in the Model B rotary to run these thru the stages to polish. As the target rocks shrank during each stage I added more fill to make up the lost volume which resulted in about 40 to 45% fill. The picture below was from one batch, of 3 different frost-prone materials, Tigereye, Ark Quartz Crystal and Apache Tears. I do add a good bit of saved slurry to each stage including extra saved polish to help cushion. Just note that there are no large pieces in the run. IMG_1811 by Findrocks, on Flickr Very impressive results Hank!  |
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waterboysh
spending too much on rocks
Member since April 2021
Posts: 386
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Post by waterboysh on Nov 29, 2023 10:10:39 GMT -5
Definitely don't need a vibe. In fact, I found it really finicky to get it just right in the vibe and found doing them rotary to be easier. About half of these were done in a 3lb rotary because my Lot-O motor was dead at the time and the other half in the Lot-O. My method is slightly different in that I use media in my rough stage and pack stages 2+ more tightly than normal. This makes it take longer but I'm happy with the results I get. I posted about it here on Reddit.  |
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Post by Bob on Dec 1, 2023 18:12:05 GMT -5
OMG I loved your starting post! I tumbled a batch of it in 2015 and it came out fine, but I have never done it successfully since to my great frustration. The only variable I can think of it the polish was brand new out of the box, but I've not bought new polish in many years and just keep using it over and over. Everything seems to come out great, jaspers, agates, and many other things but not obsidian. I'm tumbling a piece of it now a bit larger than a grapefruit but it's still in 220. Your post made me laugh and it made me wince but it could have been me! Share misery brings company and all that.
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Post by velodromed on Dec 2, 2023 6:51:25 GMT -5
OMG I loved your starting post! I tumbled a batch of it in 2015 and it came out fine, but I have never done it successfully since to my great frustration. The only variable I can think of it the polish was brand new out of the box, but I've not bought new polish in many years and just keep using it over and over. Everything seems to come out great, jaspers, agates, and many other things but not obsidian. I'm tumbling a piece of it now a bit larger than a grapefruit but it's still in 220. Your post made me laugh and it made me wince but it could have been me! Share misery brings company and all that. Wait what?!? I gotta see this. If you wouldn’t mind posting pics of it in a separate post someday, that would be great. Or if you already have a post of it out there, please let me know. Size of a grapefruit, dang… |
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Post by susand24224 on Dec 3, 2023 21:50:12 GMT -5
I've done it exclusively in a rotary, and also with a vibe in all states but first, mostly with good results. I used 50% filler and also added ivory soap scrapings to thicken the slurry. I have not mixed Apache tears with obsidian and have heard that this is not a good thing to do from others. I've never dry polished anything, although I'm thinking about it with fluorite and hematite, nor have I ground out chips, etc. (not that I haven't had any) since when I first started tumbling I had no way to do that. Two things to watch out for: (1) not all obsidian is created equal; some is much more prone to chipping than others; and (2) when polishing in a rotary (before I had the vibe) with Rockshed AO, I often had to let it go a month or longer before getting a good polish. Simultaneously with getting a vibe, I also started using Rapid Polish, which works much quicker for me than the Rockshed's AO.
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waterboysh
spending too much on rocks
Member since April 2021
Posts: 386
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Post by waterboysh on Dec 4, 2023 10:28:15 GMT -5
I've never dry polished anything, although I'm thinking about it with fluorite and hematite Completely OT from the OP, but if you do try it with hematite, let me know how it goes if you don't mind. I'm got some going in coarse right now. Some materials behave pretty differently but yet I don't see many guides out there. I have a feeling that after the initial shaping where the rough bits were knocked off... that not only is it changing shape from grinding, but that the material is also a little malleable. I swear it feels smooth and not smooth at the same time. I'm not sure how to describe it other than I think the rocks are making smooshy spots on each other. Also... I discovered very quickly that if I load my barrel like normal it'll overload my tumbler. Hematite is about twice as dense as agate, so a similarly loaded barrel was a lot heavier. I actually had to take a good deal out and replace it with fillter material. Using some junk filler rocks and pea gravel to fill in the space. |
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Post by Bob on Dec 4, 2023 15:47:23 GMT -5
...hematite, let me know how it goes if you don't mind. I'm got some going in coarse right now. Some materials behave pretty differently but yet I don't see many guides out there. I have a feeling that after the initial shaping where the rough bits were knocked off... that not only is it changing shape from grinding, but that the material is also a little malleable. I swear it feels smooth and not smooth at the same time. I'm not sure how to describe it other than I think the rocks are making smooshy spots on each other. Hematite is weird. I'm usually tumbling a little bit of it and have been for years. Not much more than 50% seems to come out okay. Some pieces get worse as I go along, developing porous or weak areas which I've learned to just discard before wasting more time on them. There are also times when it looks just great going into polish yet bad areas develop in polish which is very aggravating. Just last night, 5 pieces that were going great developed weak areas in 600 grit even though coming out of 200 they looked great. I too have wondered how it would react to dry tumbling materials but have never tried it. |
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Post by susand24224 on Dec 5, 2023 2:40:14 GMT -5
I've never dry polished anything, although I'm thinking about it with fluorite and hematite Completely OT from the OP, but if you do try it with hematite, let me know how it goes if you don't mind. I'm got some going in coarse right now. Some materials behave pretty differently but yet I don't see many guides out there. I have a feeling that after the initial shaping where the rough bits were knocked off... that not only is it changing shape from grinding, but that the material is also a little malleable. I swear it feels smooth and not smooth at the same time. I'm not sure how to describe it other than I think the rocks are making smooshy spots on each other. Also... I discovered very quickly that if I load my barrel like normal it'll overload my tumbler. Hematite is about twice as dense as agate, so a similarly loaded barrel was a lot heavier. I actually had to take a good deal out and replace it with fillter material. Using some junk filler rocks and pea gravel to fill in the space. Hi, I sent you a PM with some detail. |
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Post by Bob on Dec 9, 2023 22:49:38 GMT -5
OMG I loved your starting post! I tumbled a batch of it in 2015 and it came out fine, but I have never done it successfully since to my great frustration. The only variable I can think of it the polish was brand new out of the box, but I've not bought new polish in many years and just keep using it over and over. Everything seems to come out great, jaspers, agates, and many other things but not obsidian. I'm tumbling a piece of it now a bit larger than a grapefruit but it's still in 220. Your post made me laugh and it made me wince but it could have been me! Share misery brings company and all that. Wait what?!? I gotta see this. If you wouldn’t mind posting pics of it in a separate post someday, that would be great. Or if you already have a post of it out there, please let me know. Size of a grapefruit, dang… About 3.5 lb.   |
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Post by velodromed on Dec 10, 2023 8:07:56 GMT -5
Wait what?!? I gotta see this. If you wouldn’t mind posting pics of it in a separate post someday, that would be great. Or if you already have a post of it out there, please let me know. Size of a grapefruit, dang… About 3.5 lb. Good grief that is going to be something else when it’s done! So far, it’s looking really nice and well shaped. |
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dillonf
fully equipped rock polisher
Hounding and tumbling
Member since February 2022
Posts: 1,622
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Post by dillonf on Dec 10, 2023 8:10:07 GMT -5
Definitely don't need a vibe. In fact, I found it really finicky to get it just right in the vibe and found doing them rotary to be easier. About half of these were done in a 3lb rotary because my Lot-O motor was dead at the time and the other half in the Lot-O. My method is slightly different in that I use media in my rough stage and pack stages 2+ more tightly than normal. This makes it take longer but I'm happy with the results I get. I posted about it here on Reddit. Awesome results. Thanks for the reddit link. Being the gluten for punishment that I am this post inspired me to buy some obsidian . . . |
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dillonf
fully equipped rock polisher
Hounding and tumbling
Member since February 2022
Posts: 1,622
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Post by dillonf on Dec 10, 2023 8:13:15 GMT -5
Wait what?!? I gotta see this. If you wouldn’t mind posting pics of it in a separate post someday, that would be great. Or if you already have a post of it out there, please let me know. Size of a grapefruit, dang… About 3.5 lb. I'd be interested to understand your process with this. I've just started doing larger pieces. Is it tumbling by itself with filler material? If so what type of filler are you using? |
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Post by Bob on Dec 10, 2023 14:33:21 GMT -5
I'd be interested to understand your process with this. I've just started doing larger pieces. Is it tumbling by itself with filler material? If so what type of filler are you using? Even though the polish at the end has kind of escaped me on obsidian most of the time, I've gotten pretty good at getting it there. Although this is the largest for me, I've quite quite a few in golf-ball to lemon size range ready for polish when I get the courage to try the final step again. This one has lost about 1/4th of its mass due to some trimming and quite a bit of time in 80 grit. I was wrong that it was in 220, it's still in 80. This one is in a 12lb rubber barrel. I have pieces of amazonite in with it, maybe 4-5 up to golf ball size, and the rest is just quartz gravel smalls for cushioning most around 1/2". Progress is slow and not as much can be seen done in a week as I would like. But there are only a couple of places left, and it will probably be done in 2 more weeks. Sometimes on the larger pieces, they will almost be done and then suddenly there is a new chip gone, or small crack. I'm never entirely certain if these arise due to some internal defect that was always there, or some impact that occurred in tumbling. |
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dillonf
fully equipped rock polisher
Hounding and tumbling
Member since February 2022
Posts: 1,622
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Post by dillonf on Dec 10, 2023 14:46:51 GMT -5
I'd be interested to understand your process with this. I've just started doing larger pieces. Is it tumbling by itself with filler material? If so what type of filler are you using? Even though the polish at the end has kind of escaped me on obsidian most of the time, I've gotten pretty good at getting it there. Although this is the largest for me, I've quite quite a few in golf-ball to lemon size range ready for polish when I get the courage to try the final step again. This one has lost about 1/4th of its mass due to some trimming and quite a bit of time in 80 grit. I was wrong that it was in 220, it's still in 80. This one is in a 12lb rubber barrel. I have pieces of amazonite in with it, maybe 4-5 up to golf ball size, and the rest is just quartz gravel smalls for cushioning most around 1/2". Progress is slow and not as much can be seen done in a week as I would like. But there are only a couple of places left, and it will probably be done in 2 more weeks. Sometimes on the larger pieces, they will almost be done and then suddenly there is a new chip gone, or small crack. I'm never entirely certain if these arise due to some internal defect that was always there, or some impact that occurred in tumbling. Very cool! Thanks for the info! I've got some large pieces of coprolite going (not as big as your obsidian), and I am experiencing what you describe. I'm using carnelian, bahia agate and ceramic as filler, but I am starting to think the carnelian and bahia are too hard for the coprolite. I always enjoy your posts - you are definitely doing some cool and different stuff which is nice to see. |
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Post by Bob on Dec 10, 2023 15:51:36 GMT -5
One of my goals someday is to have on a shelf some baseball size rocks of many types, perfectly polished and defect free. So when I visit rock shops, I look in dark dusty corners and outside in piles because few people buy the larger pieces. There are a number in process. The few I have done are: Kambaba "jasper", dalmatian stone, green aventurine, psilomelane (not pure), Tecovas (I think) chert, quartzite, and Brazilian agate. And quite a few beach rocks from rivers and oceans that are unidentified but probably mostly igneous rocks like basalt and the like. You have to judge the rough as to how it's going to go with trimming off bad spots--so sometimes the rock has to be almost twice as large in the beginning to come out right in the end. I trim all these by hand on a 10" saw. Some cuts take almost 10 mins and my hands almost cramp up at times.
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Post by velodromed on Dec 11, 2023 6:33:18 GMT -5
One of my goals someday is to have on a shelf some baseball size rocks of many types, perfectly polished and defect free. So when I visit rock shops, I look in dark dusty corners and outside in piles because few people buy the larger pieces. There are a number in process. The few I have done are: Kambaba "jasper", dalmatian stone, green aventurine, psilomelane (not pure), Tecovas (I think) chert, quartzite, and Brazilian agate. And quite a few beach rocks from rivers and oceans that are unidentified but probably mostly igneous rocks like basalt and the like. You have to judge the rough as to how it's going to go with trimming off bad spots--so sometimes the rock has to be almost twice as large in the beginning to come out right in the end. I trim all these by hand on a 10" saw. Some cuts take almost 10 mins and my hands almost cramp up at times. I’d love to see a picture of the Tecovas Jasper, or the one that you think is it. I also love larger polished rocks I’ve been slowly working my way up and size over the year. |
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Post by Bob on Dec 13, 2023 11:37:39 GMT -5
One of my goals someday is to have on a shelf some baseball size rocks of many types, perfectly polished and defect free. So when I visit rock shops, I look in dark dusty corners and outside in piles because few people buy the larger pieces. There are a number in process. The few I have done are: Kambaba "jasper", dalmatian stone, green aventurine, psilomelane (not pure), Tecovas (I think) chert, quartzite, and Brazilian agate. And quite a few beach rocks from rivers and oceans that are unidentified but probably mostly igneous rocks like basalt and the like. You have to judge the rough as to how it's going to go with trimming off bad spots--so sometimes the rock has to be almost twice as large in the beginning to come out right in the end. I trim all these by hand on a 10" saw. Some cuts take almost 10 mins and my hands almost cramp up at times. I’d love to see a picture of the Tecovas Jasper, or the one that you think is it. I also love larger polished rocks I’ve been slowly working my way up and size over the year. I know these photos aren't that great because the rock is large and handheld and I'm using my mediocre cellphone camera. It's either 4 or 6 lbs I forget which. Even though it looks like there are cracks, there are none--not a single crevice or crack. It's defect free. All those lines that look like cracks are completely silicified. This took over a year and might be the largest shiny rock I've tumbled. Some beach rocks are larger but I had to stop at 1,000 grit because the first test in polish showed they won't polish. It's not totally shiny because I think the layer it came from wasn't truly 100% silicified even though the feel of the texture of the rock makes you think it ought to polish perfectly. Best guess is Tecovas Formation layer. It took almost 3 months to grind away a small defect in one shallow concavity. It was invisible if I wet it with my saliva but I enjoy going all the way to perfection.     |
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