pizzano
Cave Dweller
Member since February 2018
Posts: 1,390
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Post by pizzano on Feb 22, 2018 22:21:40 GMT -5
Looking for any tips on Vibe tumbling this material......
It's really a gorgeous powder blue banded/white "agate"........especially if cut against the grain to exposed the bands. The "earth" clinging around the outer edges cleans up pretty easy without losing to much volume..........that's when I discovered the softness of the white bands.
It's listed as an Agate (7 Mohs) and I have found it does not respond to the typical cycles I run all my Agates at. The white bands seem to be softer and collect/absorb the finer grits from stages 400 through polishing.
Just finished (well, I thought I was finished) a batch vibed with other "agates" of various sizes..........all the other agates polished up as expected, the Blue Lace surfaced polished to a gloss, but all of the banded crevices and small fractures collected so much other material, they really dissapoint.
I carefully checked each batch cycle, brushed cleaned after each cycle........started noticing the aberrations after the 120/220 cycle. Kept going thinking it would resolve it's self.......not....!
They have now been set-a-side. Thinking about throwing them back into a 120/200 cycle (vibe) with other (7 Mohs) material I have rotary ginding right now.
I might mention that I did not start them out in a rotary because I was afraid they would lose to much volume and fracture.......60/90 vibe.
Any thoughts are appreciated......Thanks.....!
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Post by grumpybill on Feb 23, 2018 6:38:31 GMT -5
One of things I'm experimenting with for stones that contain both hard and soft minerals is to pre-shape them (if necessary), skip the 60/90 stage, and run them through a shortened 120/200 stage in my Lot-O vibe. Haven't moved any on, yet, but there seems to be less undercutting.
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pizzano
Cave Dweller
Member since February 2018
Posts: 1,390
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Post by pizzano on Feb 23, 2018 10:34:04 GMT -5
My only other experience so far with soft/hard minerals had been the Opal/Granite mix....I knew going into that it would be a challenge. Started those batches with 120/220. Since the Blue Lace material is supposed to be an Agate of the 7Mohs scale, thought blended with other Agates and 60/90 there would be no problems........my lack of experience and attention to detail caught up with me this time.
I'm still learning how to remedy "undercutting" issues with other stones......this one caught me completely off-guard.
Not going to give up on these.......they are to "pretty" to spoil.......I'll keep experimenting.........Thanks for the tip.
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sactorick
having dreams about rocks
gemfield
Member since October 2017
Posts: 67
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Post by sactorick on Feb 25, 2018 12:22:58 GMT -5
I picked up some blue lace at Quartzsite in January. I tumbled some for two weeks in grit #1 and moved them to step two. After a week, I wasn't satisified so I put them back in the 1st grit for another week. I'll check them this afternoon. So far, it hasn't been positive for me.I think I need to get better skilled at choosing rocks.. There were too many fractures and soft cyrstals on the ones I brought home.
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Post by pauls on Mar 2, 2018 15:19:12 GMT -5
Keep trying, Blue lace is beautiful when you get it right.
The way I do hard/soft materials is to get it through the coarser grits quickly, dont give it time to undercut. So I pregrind the edges and hollows,tumble then grind the protruding hard bits again before moving it on to finer grits, keep it in 220 only until its removed any grind marks.
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sactorick
having dreams about rocks
gemfield
Member since October 2017
Posts: 67
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Post by sactorick on Mar 7, 2018 7:40:24 GMT -5
Keep trying, Blue lace is beautiful when you get it right. The way I do hard/soft materials is to get it through the coarser grits quickly, dont give it time to undercut. So I pregrind the edges and hollows,tumble then grind the protruding hard bits again before moving it on to finer grits, keep it in 220 only until its removed any grind marks. I'll give that a try pauls. Thanks for the tips.
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SirRoxalot
freely admits to licking rocks
Member since October 2003
Posts: 790
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Post by SirRoxalot on Mar 11, 2018 17:46:22 GMT -5
You sure it's undercutting, or just has minute pits that trap grit? I've tumbled pounds of blue lace and slabbed some, never had any trouble, but did notice the center of the vein often had tiny openings, making it unsuitable for cabbing.
Very strange problem, hope you solve it.
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pizzano
Cave Dweller
Member since February 2018
Posts: 1,390
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Post by pizzano on Mar 11, 2018 19:43:07 GMT -5
You sure it's undercutting, or just has minute pits that trap grit? I've tumbled pounds of blue lace and slabbed some, never had any trouble, but did notice the center of the vein often had tiny openings, making it unsuitable for cabbing. Very strange problem, hope you solve it. It seems that the "white" bands (veins) may be a bit softer, that's where I'm getting the undercutting.......also the place where grit lodges. I brush the heck out of each cycle, even used borax and or dish soup in the finer grit cycles to help. Still have pieces that do not come "clean".
I'm in the pre-polish stage now with Blue that didn't make the cut last go around.......have lost some volume, but much of the problems I had seem to have sorted themselves out due to more grinding with other similar agates........was really hoping for a better end product........thanks for the info...!
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