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Post by aDave on Aug 30, 2020 13:41:18 GMT -5
Recently came into an amazing deal on some 80 grit (VS the 90 I typically use; mixing up my own 60/80 blend). Curious to hear how much of a difference you guys think it will make (or if someone has experience with it). Anyone? Is it SiC or AO?
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Post by Mel on Aug 30, 2020 13:43:13 GMT -5
Recently came into an amazing deal on some 80 grit (VS the 90 I typically use; mixing up my own 60/80 blend). Curious to hear how much of a difference you guys think it will make (or if someone has experience with it). Anyone? Is it SiC or AO? SiC. I was thinking of trying AO for all my stages, and see how I like it, but I haven't really looked into AO for much other than a polish.
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Post by aDave on Aug 30, 2020 13:50:44 GMT -5
SiC. I was thinking of trying AO for all my stages, and see how I like it, but I haven't really looked into AO for much other than a polish. I've not used graded 80, so I can't say for sure how it will work. I'd have to think you aren't going to be hurt by by making your own blend. I'd recommend that you (at least) stick to SiC for your first stage coarse grind. AO reportedly has more of a smoothing action, where SiC is a better cutting material. I haven't tested, but I seem to recall seeing posts where folks believed that AO was not as efficient as SiC in the first stage. Many here, myself included, use AO from 500 through polish.
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Post by Mel on Aug 30, 2020 14:19:29 GMT -5
Yep, that's my plan!
Right now I'm typically doing a 60/90 mix for first stage, then a 220 (sometimes 150/220 blend, I really need to keep better notes about the results...), a 600F and a 1200(?) titanium dioxide polish (moving to AO 1200 for polish soon though, my supply of TD is running out). Wanted to try TXP like the RockTumbling.com suggests but couldn't find it in Canada. Hmmm.
I can't see the 10 grit difference making any extremely big difference in the coarse stage, but some people are finicky about sizes.
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Post by knave on Aug 30, 2020 15:38:14 GMT -5
Yep, that's my plan! Right now I'm typically doing a 60/90 mix for first stage, then a 220 (sometimes 150/220 blend, I really need to keep better notes about the results...), a 600F and a 1200 titanium dioxide polish (moving to AO 1200 for polish soon though, my supply of TD is running out). Wanted to try TXP like the RockTumbling.com suggests but couldn't find it in Canada. Hmmm. I can't see the 10 grit difference making any extremely big difference in the coarse stage, but some people are finicky about sizes. The truth is grit sizes are constantly being reduced as they grind, and the larger grits will break down as the tumble progresses. Only thing, 40 or 30 grit will not break down well in a small 6” rotary.
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Post by aDave on Aug 30, 2020 19:01:58 GMT -5
Right now I'm typically doing a 60/90 mix for first stage, then a 220 (sometimes 150/220 blend, I really need to keep better notes about the results...), a 600F and a 1200 titanium dioxide polish (moving to AO 1200 for polish soon though, my supply of TD is running out). Wanted to try TXP like the RockTumbling.com suggests but couldn't find it in Canada. Hmmm. While it may be labeled as "polish," what you are planning on using is more along the lines of a pre-polish due to its size. Most real polishes start at 3 microns which is about 8,000 (TXP) but many end up using something around 13,000 to 14,000 (AO). Have you used only 1200 yet? If so, how were your results? Maybe greig will jump in to offer up his source of polish. He's also in Canada. ETA: Are you using a vibe or rotary? If a vibe, you might be able to get a decent finish running the 1200 a bit longer. Many of us with Lot-Os have gotten a pretty decent finish by simply running AO 500 for an extra day or so.
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Post by Mel on Aug 30, 2020 20:50:10 GMT -5
All rotary at this point. I plan to get a vibratory, but so far, I can't bring myself to pull the trigger (odd; my garage has no room but my wallet has TONS of empty space...anyone have a fix?).
Right now I'm polishing with titanium dioxide, which does a pretty good job for me when I don't measure wrong (that was an adventure I'd rather not repeat!), but want to try something different. Also read that TD can be considered mildly carcinogenic (over long, long term exposure but still) so I'm surprisingly OK to find a new method.
I used some AO a few years back and it worked wonderfully but I couldn't tell you the size if my life depended on it. It was from one of those "4 stage packs" so you know it was nothing super fancy. Most of the hobby sites I found quoted 1200 as a polish in a rotary so that's what I went with.
I'll chalk the 1200 up to a learning experience (seem to get a lot of those lately). It should arrive next week, and if it's only good as pre-polish, well, then it's pre-polish! Will keep you posted.
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quartz
Cave Dweller
breakin' rocks in the hot sun
Member since February 2010
Posts: 3,352
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Post by quartz on Aug 30, 2020 21:41:15 GMT -5
I've used straight grade 80 SiC for several years, it all turns to smoosh as it breaks down, you won't be able to tell the difference.
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Post by Bob on Aug 30, 2020 21:57:23 GMT -5
No, definitely. I use almost 50 lbs per month.
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Post by rmf on Aug 31, 2020 8:59:13 GMT -5
Mel from Yuma & Spokane A lot of rocks I have tumbled are fresh out of a crusher or have been hand hammered. the sharp edges take a long time to get rounded the way I like them so I quit using 60/90 grit years ago and started using 46/70. It grinds faster and since it is physically bigger takes longer to breakdown to fines. It also washes out easier and settles to the bottom of the 5gal bucket faster so I can reuse if any is left. You will not notice any significant difference in 60/80/90 Get what is cheap. As for AO in coarse, it is not has hard as SiC. I have tried AO in coarse and Garnet grit in coarse and much prefer the SiC for coarse.
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Post by greig on Aug 31, 2020 12:47:12 GMT -5
I don't have a good source in Canada for grit that I can reliably recommend is quality and that polish size matches the label. Some outlets sell name brand grits and polishes (eg. Lortone) which are an expensive way to get small quantities. Also, I was given a kit of stage 1-4 plus some plastic beads from Poly Plastics (for a video) and it seemed good. It can be found on Canada Amazon.
My last order for grit was from Robert Hall Originals where I told him how many pounds of each stage I wanted. I bought stage 1 60/90, stage 2 150/220 and stage 3 500 SC. I cannot tell the difference in my rotary tumbling between SC and AO for stage 3. I use AO for stage 4, but many packages don't say the size. Still, it seems to work OK, if marked as stage 4 polish. I have tried other polishes and always return to AO.
That said, I still wonder at the benefit of mixed grits (such as 60/90) or if mixed is really better than a single grit? If so, then why not run stage 1 & 2 grits 60/90/150/220 together? Sounds dumb but it would be fun to experiment. I have not noticed any difference in stage 1 by running 80 grit vs 60/90. Both seem to round my rocks at about the same pace.
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Post by Bob on Aug 31, 2020 14:10:34 GMT -5
I do my rough grind in 50 or 60 and buy large quantities of it. Then I do a week in 80 before going to 220. That's what I've been doing about 3 years after doing 2 years before that starting in 80.
The larger grit is only a little bit cheaper to buy, that's not why. It seems to me rough grind goes a little faster though, but I've never truly measured it. So I've developed a feel for what rocks can go from rough grind next to that week in 80. It depends upon the material, but if the crack or pit or small concavity is .5mm or less, it will usually come out in the week in 80. Sometimes not, and it will go for 2 weeks in 80. So I leave my rocks in rough grind until just a little bit left of defects to take out in one week in 80.
Sometimes if a rock look almost perfect coming out of 50 or 60, I'll just skip 80 and go directly to 220. I'm lucky to live only 1 hour from a major grit reseller in Okla City. They will ship too. Their name is JESCO. Ask for KC if you contact them and say Bob in Stillwater mentioned it. I pick up in person and have to pay sales tax because I live in OK. If I buy from KN, I pay no sales tax but have to pay shipping. JESCO is usually the best deal unless KN is running one of those flat rate box shipping specials which they do from time to time. Of course, I avoid shipping with JESCO because I have to do to Okla City now and then anyway.
Since I tumble a lot of rocks larger than apples that I find in the field, that have all kinds of crud and lichens and weather rind, I like how that 50 or 60 just strips them down quickly and lets me know in a week if I should continue, cleave, saw, throw away, or what. The two most exciting times in tumbling for me are after the first week in rough grind with field found rocks, and the first time I see them after polish.
I was at a rock shop in Victoria, BC a couple of years ago. I could hardly believe how expensive grit was. No way I could afford to tumble monster rocks in Canada. I think my grit bill runs about $45/mo or something like that.
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Post by Mel on Sept 1, 2020 10:00:21 GMT -5
You guys are giving me so much valuable info. This forum is downright dangerous!! I figured the 80 can't wreck anything. Plus it was cheap, and available; 90 was going to be five weeks (!). No thanks. rmf , I really like the ability to recover some of it too. More grinding for less bucks is OK in my books. Especially since someone may have found a great deal on another 12 pound tumbler..... I had such a troublesome time sourcing grit for a price I could afford -- no rock shop within six hours of me -- that when I started I was buying the small "kits" and then moved onto buying bulk as much as I could cart home (closed shop is 6 hours away). Now I've gotten sick of paying for shipping and just buy a couple hundred pounds at a time, ship it via freight, and sell off extra when people ask me for it.
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Post by Bob on Sept 1, 2020 11:24:46 GMT -5
I'm probably close to buying a big steel drum of rough grit. It would weigh over 500lbs, so I'd need to get a friend or two from the gym to help me out, but financially it makes sense given how much I use.
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Post by Mel on Sept 1, 2020 19:41:16 GMT -5
Well, I have a source for 300 pounds, but 500 just sounds like way more fun.
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