DogStar
off to a rocking start
Member since January 2018
Posts: 15
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Post by DogStar on Jan 26, 2018 20:51:23 GMT -5
Ive read you can use a tumbler to do the final polish on cabs, my question is in 2 parts.
1st at what stage of the cabbing process? I was thinking after the first two wheels of the flat lap (in my case the diamond rough grinding and the brown course sanding disk)?
2nd into what stage of tumbling?
I have both a rotatry and vibratory tumbler, I understand the vibratory one is shorter, so better for impatient people like me?
Thanks!!!!
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zarguy
fully equipped rock polisher
Cedar City, Utah - rockhound heaven!
Member since December 2005
Posts: 1,791
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Post by zarguy on Jan 26, 2018 22:58:21 GMT -5
I shape cabs on my 60 grit sintered wheel, fine tune them on the 220 grit plated wheel then put them in the Loto vibe tumbler with 220 grit. From there, just follow the usual grits and times. Lynn
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Post by gmitch067 on Jan 27, 2018 1:28:18 GMT -5
I only do hand cabbing, hand sanding up to 1000 grit, before finishing some in the UV-18, or in the Mini-Sonic MT-4.
I do not recommend putting any cab into the vibe with anything coarser than 1000 grit. More than once I have ruined a beautiful piece due to undercutting or over-grinding softer sections... very noticeable at 220 grit, and still a problem at 600 grit.
Keep the slurry kind of thick and use small ceramics to allow multiple cabs to roll over each other (rather than stick together).
I hope this helps you.
Glenn
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Sabre52
Cave Dweller
Me and my gal, Rosie
Member since August 2005
Posts: 20,487
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Post by Sabre52 on Jan 28, 2018 10:48:57 GMT -5
Not good to finish cabs in the rotary tumbler as it tends to change shapes too much. Vibe does not change original shapes so it works well. I go to the vibe after the first three wheels. Run in fine grind only a bit to eliminate last few scratches. Should take only a day or so. Then do prepolish and polish in a separate tub in the vibe with a bunch of small polished stones to increase surface contact. Only thing you have to watch out for is undercutting in the fine grind tub if your stone has soft spots. Unfortunately, a lot of inclusions in jasper and agate can be softer. Can't usually tell till you try a particular stone type. Banded agates like Bots, Brazils, Lakers etc usually are a piece of cake. T-eggs with some matrix can have problems with the matrix portion as can moss agates, dino bone, some pet wood, and sagenitic agates. After you try a few, you will see what types will be problematic....Mel
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Post by HankRocks on Jan 28, 2018 11:39:57 GMT -5
I do not have the full setup to do the classic Cab, I rely on tumbling to polishing all my preformed Pendant stones. I do shape almost all the stones on an 80 or 120 diamond wheel. At this point I sort the rocks according to hardness and thickness, softer or thinner into one batch, hard or thicker into another. I will run the hard batch a full 8 to 10 days in 46/70 + 80 SiC with one or two recharges. The softer batch may only go 4 or 5 days on 80 SiC sometimes 220 SiC. I use Pea Gravel in both. After coarse I sort out any broken or ones with soft spots that lost their shape. They go back in the grinding cycle. My next stage for both is 80 AO with slurry saved from previous 80 AO runs, usually 8 days no recharges. Then on the polish with Micro AO for 3 to 4 days. Very satisfied with results.
The 80 AO has worked very well for me, may buy some 220 AO and try that, maybe shorten the middle stage by 2 or 3 days. The Grinding phase and experience has taught me the hardness of various materials. Tiger Eye, Quartz, some Palm and Petrified Wood can be softer. Have also learned to judge where soft spots are and cut and grind shapes to avoid them. Some of the West Texas Bouquet and Plume can have a lot of soft spots and can be frustrating to work with.
And I am still learning!
Henry
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Post by HankRocks on Jan 28, 2018 11:42:57 GMT -5
Forgot to add that I do run in Ivory bar soap between the SiC and AO stages, maybe 5 to 6 hours. Not sure that it's necessary but the soap water is always gray after the running so it's removing something.
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Post by HankRocks on Jan 28, 2018 11:43:51 GMT -5
...and the first two stages are in Rotary, the last stage in the Vib.
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