mgroothuis
starting to spend too much on rocks
Member since November 2022
Posts: 166
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Post by mgroothuis on Aug 28, 2023 19:14:52 GMT -5
I’ve been experimenting with my Lot-o. If 3 days of 500AO is the norm, then 5 must be better…I thought. On my last run, wrong! I got excessive chipping and the undercutting was exaggerated. The results were surprising. Not in a good way. If I do decide to run things longer, is it normal to add more grit after the “normal” run time?
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Post by velodromed on Aug 28, 2023 19:49:42 GMT -5
I’ve been experimenting with my Lot-o. If 3 days of 500AO is the norm, then 5 must be better…I thought. On my last run, wrong! I got excessive chipping and the undercutting was exaggerated. The results were surprising. Not in a good way. If I do decide to run things longer, is it normal to add more grit after the “normal” run time? I’ve let rocks go in AO for 5-6 days in my raytech 5 vibe with very shiny results. But I run it loaded 1/2” from the top with ceramic media that’s been through many polish stages, in a polish only designated bowl. This slows the roll to a gentle cycle. I load the bowl the same way with stages 2 and 3, except I use a different bowl loaded with ceramics and roundish aquarium agate. I do the lengthy course stages in rotary tumblers. If you add more 500 AO midway through the run you’re taking steps back. In the first couple days, that 500 AO has broken down a lot. So add your grit on day 1 and let it go for however long you want. AO doesn’t completely break down like SiC does. It keeps working the smaller it gets.
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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 Aug 28, 2023 21:17:29 GMT -5
I’ve been experimenting with my Lot-o. If 3 days of 500AO is the norm, then 5 must be better…I thought. On my last run, wrong! I got excessive chipping and the undercutting was exaggerated. The results were surprising. Not in a good way. If I do decide to run things longer, is it normal to add more grit after the “normal” run time? I too have experimented with extending the tumbling time past 48 hours in the Lot-O. In my opinion it doesn't seem to do anything "better" - the shine at 36 hours isn't noticeably better than the shine at 48 hours. I have gotten chipping and undercutting, but it does not appear to be related to tumbling time in my situations. Chipping for me seems to occur in 3 situations: 1) Slurry is too thin (too wet) and action is too fast, 2) Slurry is too dry, 3) the cycling action stops and the stones stay in one place rattling against each other. Undercutting, for me, appears to be very specific to the type of stone I'm tumbling. I haven't really worked this out yet to be honest. I think the vibe is just "too good" at getting in pits and soft spots, which makes me feel like a rotary is better for polishing material that is prone to pitting. That said - this is just a guess on my part. I haven't had any issues in the Lot-O with agates or solid jaspers, but with some varieties of quartz, kambaba, leopard jasper and some crazy lace the vibe accentuates differences in hardnesses found in the material - if that makes sense? Much more so than a rotary. Sometimes this doesn't become apparent until the polish stage which sucks because I have to dial it back to the 220 stage to fix it. That said I really like the 220 and 500 stages in the lot-o. With a good slurry two 48 hour cycles at 220 (cleanout between cycles) in the Lot-O is way better than a week of 220 in the rotary! Same for 500 grit.
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mgroothuis
starting to spend too much on rocks
Member since November 2022
Posts: 166
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Post by mgroothuis on Aug 30, 2023 7:26:11 GMT -5
I've had some seemingly softer rocks that for some reason cannot get a good polish in the vibe. They always end up with a satin finish, juuuuust on the edge of a high gloss. I figured I would try it longer.
As expected, undercutting always happens with the mica in the rock, so I too avoid tumbling them. The mica in these rocks were so fine, I figured I would try anyway. The action in my Lot-o is pretty slow, and I've been adjusting the weights in the retrofitted concrete motor to see if I can increase it. This may be a problem too.
Usually everything runs fairly well, but this batch was bad after running it so long in 500. I suppose I could have had contamination from coarser grit too.
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