Post by Jasper-hound on Jul 18, 2010 17:46:52 GMT -5
Greetings, tumblers. I know the subject heading makes me sound like an egomaniac, which I would be if I did not know the truth, which is that I finally achieved success on my obsidian, thanks to all the knowledge I gleaned from the true experts who have posted so much helpful advice on this board. Having said that, let me tell you a little bit about this batch of obsidian. First of all, while I used to tumble a lot of times in my youth, I am a newbie as an adult, and I have committed to trying to learn how to attain professional results so that my stones turn out well formed and with wet looking polish, not like the crude stones I produced during my youthful forays into the hobby (and, yes, I still have some of those stones in my possession!).
My first experience with this obsidian was a failure. Here is what I did (wrong):
1. Rotary tumbled for 3 weeks in 60/90 Sic. Obsidians were mixed with other materials--moonstones, even with some agates and jaspers.
2. Vibratory tumbled for 3 or 4 days in #220 Sic.
3. Continued in UV-10 3 more days with #600 Sic.
4. Continued in UV-10 3 more days with #1000 AO
5. Vibrated for more than a week with Cerium oxide.
*All these steps included a mixture of ceramic media plus plastic pellets for cushioning, kept separate between mesh sizes.
*I DID thoroughly (I thought) clean the stones and tumbler barrel between each step, and I DID purchase a dedicated drum for polishing on my UV-10. I did not, however "burnish" between steps.
Results? I could not get the obsidians to polish beyond a high matte gleam, and the edges of the stones began "spalling" or getting a thin white frosting. Yuck! After all that washing and care and anticipation, tumbling these obsidians was beginning to cause some resentments! So I read more online advice and retumbled as follows, yielding the results shown in the photographs:
1. Retumbled the obsidians ALONE with 60/90 in rotary tumbler for another 3 weeks. I added a few handfulls of rough Apache tears to provide some small size material to carry the abrasives between the larger stones.. This was recommended in postings I have read elsewhere on this forum. Eliminated ceramics and pellets from the diet and switched to rice hulls. I picked up a huge bale of these rice hulls--enough to fill to garbage bins with lids (to prevent rats)--from a local feed store for about nine bucks.
2. Switched to UV-10 and SKIPPED #220, going directly to #600 Sic with rice hulls for three days.
3. Stones looked great. Recharched with #1000 AO prepolish with rice hulls for two days. See my post last week: "Whoops! put pre-polish in dedicated polish drum."
4. Stones looked great, so went on to polish. This time I eschewed the cerium, choosing submicron AO polish instead. Threw about three tablespoons into the UV-10, along with fresh rice hulls.
*Note: between each grit change, I did fully was stones (as always) followed by "burnishing" by filling the UV-10 above the level of the rocks with water and adding a few table spoons of pure borax.
5. Also "burnished" the finished stones with borax for a few hours. Rinsed and hand dried to prevent water spotting.
And there you have it. The most difficult part was controlling the moisture ratio in the UV-10 to coat the stones properly but to keep sludge from building up and stalling the stones' movements. I generally achieved a pretty brisk convection movement of the stones inside the UV-10 drum. I am learning that getting this movement requires close monitoring, experience, and patience but is ESSENTIAL in attaining any sort of positive results with the UV-10.
Anyway, I am at this point perfectly satisfied with how the obsidians turned out. My next challenge will be to replicate the results. I will let you know how it goes. I know that there are others as frustrated as I have been when it comes to polishing obsidian, and I thought it would be nice to pay the board back by posting my eventual success. Thanks for reading my ramble. Craig.
My first experience with this obsidian was a failure. Here is what I did (wrong):
1. Rotary tumbled for 3 weeks in 60/90 Sic. Obsidians were mixed with other materials--moonstones, even with some agates and jaspers.
2. Vibratory tumbled for 3 or 4 days in #220 Sic.
3. Continued in UV-10 3 more days with #600 Sic.
4. Continued in UV-10 3 more days with #1000 AO
5. Vibrated for more than a week with Cerium oxide.
*All these steps included a mixture of ceramic media plus plastic pellets for cushioning, kept separate between mesh sizes.
*I DID thoroughly (I thought) clean the stones and tumbler barrel between each step, and I DID purchase a dedicated drum for polishing on my UV-10. I did not, however "burnish" between steps.
Results? I could not get the obsidians to polish beyond a high matte gleam, and the edges of the stones began "spalling" or getting a thin white frosting. Yuck! After all that washing and care and anticipation, tumbling these obsidians was beginning to cause some resentments! So I read more online advice and retumbled as follows, yielding the results shown in the photographs:
1. Retumbled the obsidians ALONE with 60/90 in rotary tumbler for another 3 weeks. I added a few handfulls of rough Apache tears to provide some small size material to carry the abrasives between the larger stones.. This was recommended in postings I have read elsewhere on this forum. Eliminated ceramics and pellets from the diet and switched to rice hulls. I picked up a huge bale of these rice hulls--enough to fill to garbage bins with lids (to prevent rats)--from a local feed store for about nine bucks.
2. Switched to UV-10 and SKIPPED #220, going directly to #600 Sic with rice hulls for three days.
3. Stones looked great. Recharched with #1000 AO prepolish with rice hulls for two days. See my post last week: "Whoops! put pre-polish in dedicated polish drum."
4. Stones looked great, so went on to polish. This time I eschewed the cerium, choosing submicron AO polish instead. Threw about three tablespoons into the UV-10, along with fresh rice hulls.
*Note: between each grit change, I did fully was stones (as always) followed by "burnishing" by filling the UV-10 above the level of the rocks with water and adding a few table spoons of pure borax.
5. Also "burnished" the finished stones with borax for a few hours. Rinsed and hand dried to prevent water spotting.
And there you have it. The most difficult part was controlling the moisture ratio in the UV-10 to coat the stones properly but to keep sludge from building up and stalling the stones' movements. I generally achieved a pretty brisk convection movement of the stones inside the UV-10 drum. I am learning that getting this movement requires close monitoring, experience, and patience but is ESSENTIAL in attaining any sort of positive results with the UV-10.
Anyway, I am at this point perfectly satisfied with how the obsidians turned out. My next challenge will be to replicate the results. I will let you know how it goes. I know that there are others as frustrated as I have been when it comes to polishing obsidian, and I thought it would be nice to pay the board back by posting my eventual success. Thanks for reading my ramble. Craig.
