Welcome to the Rock Tumbling Hobby Forum where we share a love of rocks and a sense of community as enduring as the stones we polish.
The RTH Forum of www.RockTumbling.com is an Amazon Associate site and we earn money from
qualifying purchases you make after clicking on our links such as this
Rock Tumbling Supplies on Amazon
link for instance, or any of our various product ads and banners. By clicking our links every time you begin your Amazon shopping
experience, you are generating a bit of revenue for the forum which helps us cover our expenses. Thank you for your support!
If you cannot see Amazon ad banners directly below this text, please whitelist this site in your ad blocker(s). The ads below have been hand-selected for relevant content, and your patronage directly benefits this forum community, thanks!
For 2 or 3 years now I'm been accumulating obsidian for another attempt at polishing. I only do rotary. It will be my 3rd attempt. Once was long ago before I had much experience with any material. Another time was 3 or so years ago, after not touching it for about 5 years. Several batches each time. Some went okay, some not okay, very few went great. I have perhaps 10 pieces with a high shine after--in total--perhaps polishing 200 pieces attempted. All kinds from Apache tears to black or other types.
What I had been doing is using polish, whether cerium, alum, or tin, and cushioning plastic beads.
My black plastic beads are purchased from Kingley-North, float, and seem to last almost forever. Some are now perhaps 8 years old and maybe only have lost 25% of their size. Those are the ones used in 220, 600, 1,000 grit. The ones used only in polish look like the day they were purchased.
The white ones from Rock Shed that don't float, feel to me like they are probably nylon. Because they can't be poured off first, due to sinking, I do not like them and threw them all away. And those I didn't pick out, but just left in rock batches, eventually ground away to nothing within 2 years. If you press on one with your fingernail, you sense a tiny bit of give in the surface. The black ones look and feel to me like they might be polystyrene. I can't feel any give in the surface. I love how easy it is to pour them off first.
I've been surprised how little wear occurs on those black ones even in 220 grit. Those things must really be tough. I have wondered a few times if they are tough enough in polish to not provide enough cushioning for delicate things like obsidian.
For that reason, I'm thinking about trying something different this time, such as getting some of those different plastic beads from Rock Shed just for this polish run in obsidian, or maybe trying to cut up pieces of leather thing I've read that others use.
Does anyone with good obsidian polish experience think my idea might have any validity? I have plenty of time because I don't be trying to polish obsidian again for several months.
I use polished small and medium ceramics with my tumbled obsidian. For polish (in a 3-lb barrel) I'll add about a pound of obsidian pieces, then fill up the volume of the barrel to about 80% or 85% with these ceramics. What you get in this situation (I think) is very little movement of the rocks. I think it's more like the rocks will stay in one place and sort of slide back and forth a little against the ceramics. I believe this slows everything down, but also prevents the rocks from coming into contact with each other in a damaging way. The polish I obtain is pretty nice (and has been consistent so far) using this method, even though the ceramics are much harder than the obsidian. I am replacing the ceramics for single-use beach pebbles in my set up now, and am a little concerned that they won't play nice with the homogenous ceramics. As soon as I test this I'll make a post about it! I think, if you put enough leather in the barrel, it would have the same effect, but with more cushioning I suppose?
I look forward to following this thread to see how other people deal with this difficult rock...
Last Edit: Feb 14, 2024 14:58:27 GMT -5 by hplcman: Added a sentence
sphereguy Matt thickens his obsidian batches with corn syrup, and makes the best tumbles. He also removes everything that is less than completely rounded each step so the pointed edges cannot scratch the adjacent rocks. I've had others recommend the leather strips as well. Since it is glass I think every stage needs to be more gentle than other things, so the surface isn't getting the micro fracturing that the next step will have to remove. I am interested in what you learn, we have a couple buckets of NM tears that we need to do something with.
“You preachers of equality, the tyrannomania of impotence clamors thus out of you for equality: your most secret ambitions to be tyrants thus shroud themselves in words of virtue. Aggrieved conceit, repressed envy—perhaps the conceit and envy of your fathers—erupt from you as a flame and as the frenzy of revenge.” —Friedrich Nietzsche
I use polished small and medium ceramics with my tumbled obsidian. For polish (in a 3-lb barrel) I'll add about a pound of obsidian pieces, then fill up the volume of the barrel to about 80% or 85% with these ceramics. What you get in this situation (I think) is very little movement of the rocks. I think it's more like the rocks will stay in one place and sort of slide back and forth a little against the ceramics. I believe this slows everything down, but also prevents the rocks from coming into contact with each other in a damaging way. The polish I obtain is pretty nice (and has been consistent so far) using this method, even though the ceramics are much harder than the obsidian. I am replacing the ceramics for single-use beach pebbles in my set up now, and am a little concerned that they won't play nice with the homogenous ceramics. As soon as I test this I'll make a post about it! I think, if you put enough leather in the barrel, it would have the same effect, but with more cushioning I suppose?
I look forward to following this thread to see how other people deal with this difficult rock...
Well, that blows up my idea that softer cushioning might be one of the secrets to obsidian polishing!
Post by waterboysh on Feb 14, 2024 15:55:46 GMT -5
I have tumbled obsidian in both rotary and in my Lot-O with good results. In both cases, for the polish stage I switch the media to already polished quartz pea gravel and aim for at least 50% media by volume. I also added 2 Tbsp of sugar per rated pound of barrel capacity.
Post by velodromed on Feb 14, 2024 15:57:30 GMT -5
I wonder what would happen if you tumbled obsidian with glass? You know, Shiner Boch and Topo Chico bottles. That’s what I think I’ll try first when I finally get to my batch. Or perhaps relatively smallish, softer, smooth beach rocks I collected in Washington. I’m thinking this since it’s good to stick with similar Mohs when tumbling. Except quartz, because of the more delicate crystal structure. Hmmm, maybe quartz would be something to try to tumble it with. It’ll be fun experimenting someday.
I use polished small and medium ceramics with my tumbled obsidian. For polish (in a 3-lb barrel) I'll add about a pound of obsidian pieces, then fill up the volume of the barrel to about 80% or 85% with these ceramics. What you get in this situation (I think) is very little movement of the rocks. I think it's more like the rocks will stay in one place and sort of slide back and forth a little against the ceramics. I believe this slows everything down, but also prevents the rocks from coming into contact with each other in a damaging way. The polish I obtain is pretty nice (and has been consistent so far) using this method, even though the ceramics are much harder than the obsidian. I am replacing the ceramics for single-use beach pebbles in my set up now, and am a little concerned that they won't play nice with the homogenous ceramics. As soon as I test this I'll make a post about it! I think, if you put enough leather in the barrel, it would have the same effect, but with more cushioning I suppose?
I look forward to following this thread to see how other people deal with this difficult rock...
Well, that blows up my idea that softer cushioning might be one of the secrets to obsidian polishing!
Maybe more cushioning and a fuller barrel both accomplish the same thing, avoiding violent collisions between the pieces being tumbled.
Last Edit: Feb 14, 2024 22:57:40 GMT -5 by Rockoonz
“You preachers of equality, the tyrannomania of impotence clamors thus out of you for equality: your most secret ambitions to be tyrants thus shroud themselves in words of virtue. Aggrieved conceit, repressed envy—perhaps the conceit and envy of your fathers—erupt from you as a flame and as the frenzy of revenge.” —Friedrich Nietzsche
Post by whyofquartz on Feb 15, 2024 7:26:50 GMT -5
I was watching MichiganRocks'(JugglerGuy is I think his handle here) video where he polished rocks in sand and what I took away from that video is 'if you want to polish rocks without losing too much detail polish in only water' while he doesn't state this outright that is what I gleened
I was watching MichiganRocks'(JugglerGuy is I think his handle here) video where he polished rocks in sand and what I took away from that video is 'if you want to polish rocks without losing too much detail polish in only water' while he doesn't state this outright that is what I gleened
That’s a good video, he was doing an experiment to see if SiC is necessary or will other materials work for tumbling. Ive found the best way to keep the shape and detail in some rock is to solely run them in a vibratory tumbler. I do this often with certain crystals and other rocks that I want to keep a more natural shape or have a special features I don’t wanna lose. I know vegasjames tumbles candy rhyolite with just water and it turns out looking great. I think he uses a rotary for that. I’ve never tried it myself though.
Last Edit: Feb 15, 2024 14:20:28 GMT -5 by velodromed
I was watching MichiganRocks'(JugglerGuy is I think his handle here) video where he polished rocks in sand and what I took away from that video is 'if you want to polish rocks without losing too much detail polish in only water' while he doesn't state this outright that is what I gleened
That’s a good video, he was doing an experiment to see if SiC is necessary or will other materials work for tumbling. Ive found the best way to keep the shape and detail in some rock is to solely run them in a vibratory tumbler. I do this often with certain crystals and other rocks that I want to keep a more natural shape or have a special features I don’t wanna lose. I know vegasjames tumbles candy rhyolite with just water and it turns out looking great. I think he uses a rotary for that. I’ve never tried it myself though.
I use the rotary (12 pound barrels) for a month, then put them in the UV-18 vibe tumbler for a week all with just water.
I use the chips from breaking up rocks as my fill to cushion the stones and to act as an "abrasive" to clean out the nooks and crannies.
Have also done this method for common chalcedonies and jaspers, which works pretty good, but not as high of a polish as with the candy rhyolite. My guess is that the rhyolite being sightly softer of grinding away creating a smoother surface to allow the stones to polish to a very high shine by grinding against each other.
Primarily Northern Nevada, near Fallon, but I did find some once in Central Nevada by Coaldale Junction.
Hmmm, the first time I found that orangey/reddish jasper I think was in the California desert. Now I've found it here and there in more than one place in that state, in New Mexico, in Texas, and now you mention Nevada. Perhaps it's a rather common material. In trying to think about anything the places I've found it have in common, the only thing I can think of is flat desert country, and lava fields, even if very old and hardly detectable, being within 50 miles. I now wonder if these particular colors--which I like a lot--in rocks are associated with volcanoes. Is the location you mentioned within that kind of distance from lava fields?
Primarily Northern Nevada, near Fallon, but I did find some once in Central Nevada by Coaldale Junction.
Hmmm, the first time I found that orangey/reddish jasper I think was in the California desert. Now I've found it here and there in more than one place in that state, in New Mexico, in Texas, and now you mention Nevada. Perhaps it's a rather common material. In trying to think about anything the places I've found it have in common, the only thing I can think of is flat desert country, and lava fields, even if very old and hardly detectable, being within 50 miles. I know wonder if these particular colors--which I like a lot--in rocks are associated with volcanoes. Is the location you mentioned within that kind of distance from lava fields?
Nevada has volcanoes all through it. We even have tons of volcanic rock all around Las Vegas.
The stuff I found in Central Nevada was found near one as I was looking for hyalite opal, which is associated with volcanoes.
This space is for temporary chat only and all posts drop off automatically and are not saved.
Members with real questions or comments that need an actual response, please post on the main forum - not here! Casual PG-13 posts only, no politics or religion please!
parfive: BOLO – Sara w/no h.
Nov 13, 2024 15:20:39 GMT -5
RickB: Surf's up - Pastrami on the hoof
Nov 13, 2024 16:44:09 GMT -5
*
Wooferhound: I make my Sandwiches without the Bread
Nov 14, 2024 12:56:46 GMT -5
amygdule: I like my meat warmed to Body TempoF... Then wrapped with a slice of Cheese
Nov 14, 2024 18:17:57 GMT -5
*
rocknrob: That was one heck of a windstorm that thankfully missed me. I guess Seatac almost hit 60mph gusts. I bet those were some fun landings
Nov 20, 2024 21:55:16 GMT -5
Welcome to the Rock Tumbling Hobby Forum where we share a love of rocks and a sense of community as enduring as the stones we polish.
The RTH Forum of www.RockTumbling.com is an Amazon Associate site and we earn money from
qualifying purchases you make after clicking on our links such as this
Rock Tumbling Supplies on Amazon
link for instance, or any of our various product ads and banners. By clicking our links every time you begin your Amazon shopping
experience, you are generating a bit of revenue for the forum which helps us cover our expenses. Thank you for your support!
