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Post by Bob on Nov 21, 2020 14:30:53 GMT -5
I started out doing 80/220/600, then polish, for a couple of years. My results were good once I got experience, and least with the basic agates, chal, cherts, etc.
I added 1,000 before polish a few years ago because I noticed it helped some materials that were touchy have a better polish. For instance, it has really helped me with lapis, sodalite and some other tricky ones. But I just decided to leave that step in there, especially because I often tumble very different materials together all the way up to before polish and this 1,000 might not help all but it might help some in nearly each batch.
I also played with very large grit before 80, because I collect so many large rocks in the field and spend months grinding many of them down. I tried 30, 40, etc. until learning that 50 is probably ideal for that first step. Sometimes 50 isn't available and I use 60 instead and the results seem pretty much the same.
So for maybe 3 years now, it's been 50/80/220/600/1,000, all SC, then polish. (Except when tumbling glass or obsidian--for those I start out in 80 because larger than that just goes too fast and is hard on them.)
Once at a mineral club meeting, some old timers heard me speak of this, at least the 50/80/220 part. A married couple who had been both rotary and vibe tumbling for several decades, who were visiting from another city, just insisted to me that if I start out with something like 50 or 60, to skip 80 entirely and go directly to 220. They said it's a waste of time and grit to have that 80 step in there between 50 or 60 and 220. They actually came on pretty strongly on that point.
I am getting low on 80 and before I bother buying any more, have been wondering about this. I am thinking about testing it and I guess this would be done by running it that way all the way and seeing if final polish was just as good.
Does anyone have an opinion this? Could I just skip 80 entirely? I'm really not wanting to talk about the upper end with fine grit such as 600 or 1,000, but only the low end with this coarse grit.
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EricD
Cave Dweller
High in the Mountains
Member since November 2019
Posts: 1,142
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Post by EricD on Nov 21, 2020 15:00:07 GMT -5
Since your 50-60 will break down to 80 within a week, I say go for it. You'll likely want to run it longer than a week so the grit breaks down to the point that your 80 step did previously.
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Post by parfive on Nov 21, 2020 15:04:10 GMT -5
I'm really not wanting to talk about the upper end with fine grit such as 600 or 1,000, but only the low end with this coarse grit. Well, how ‘bout the mid part? : ) 60/90 120/220 . . . waste of time, money & effort 500F AO polish
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EricD
Cave Dweller
High in the Mountains
Member since November 2019
Posts: 1,142
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Post by EricD on Nov 21, 2020 15:06:47 GMT -5
I'm really not wanting to talk about the upper end with fine grit such as 600 or 1,000, but only the low end with this coarse grit. Well, how ‘bout the mid part? : ) 60/90 120/220 . . . waste of time, money & effort 500F AO polish Also true. you should be able to break down 50 grit to 1000 or even higher if you let it run long enough. Heck you could get it as fine as polish if you ran it long enough.
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Post by parfive on Nov 21, 2020 15:12:48 GMT -5
No need to let it run “long enough”. A week in 500 will do just fine after 60/90.
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Post by Rockoonz on Nov 21, 2020 15:29:47 GMT -5
Our first step has been 1 week at 60/90, then open and check progress on a few rocks, and if all looks good add more grit and run it for 2 to 4 more weeks. Usually by then most of what's in the barrel is ready for 600. That's in a rotary of course. We got some 1000 grit AO to try instead of SiC. Found it while packing up to move, maybe we'll find it when we unpack.
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Post by aDave on Nov 21, 2020 16:08:23 GMT -5
I agree with the input of the "old timers" and the others here. Cut out the 80 from your current regimen, as your initial 50 gets to that size in little time. I'd even consider Rick's parfive suggestion of getting rid of the 120/220 step, and I even thought of trying that when I found one of his old posts about it. However, depending on what I had going on with some rocks, the minimal extra removal that 120/220 offered was useful for me at times. Moreover, I moved to a Lot-O which left me with rotary only for a coarse grind. For reference, my rotary regimen was: 46/70 SiC until ready to move 120/220 SiC 7-10 days 500 AO 7-10 days AO Polish for 3 weeks
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EricD
Cave Dweller
High in the Mountains
Member since November 2019
Posts: 1,142
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Post by EricD on Nov 21, 2020 18:29:13 GMT -5
No need to let it run “long enough”. A week in 500 will do just fine after 60/90. And 2 weeks in the same 60/90 will eliminate your 500 stage altogether...
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Post by parfive on Nov 21, 2020 21:19:06 GMT -5
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Post by Bob on Nov 22, 2020 0:26:53 GMT -5
Thanks for all your thoughts. I'm excited about the possibilities and plan on testing it for me right away.
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Post by HankRocks on Nov 22, 2020 4:45:48 GMT -5
I have no consistent process. My first stage can consist of 3 different grits; 46/70 SiC, 60/90 SiC, 80 SiC. The selection of which depends on the type of rocks being run. If it's mix of Agate/Jasper/Pet Wood, then the first stage will be 46/70 for initial, then about 3 days another re-charge 46/70, then 3 more days and last re-charge of 60/90 and 3 to 4 days to empty. After first stage is sorting time, advance or repeat. If advance then it goes into the "ready for 2nd stage" bucket. My logic was that the last re-charge was with slightly finer grit so to breakdown to a slightly finer grit finish. The re-charges give me a chance to check slurry and rock level. I sometimes add a few rocks at recharge time.
One main reason I use 60/90 is that I came into 50 plus pounds from my old friend, so I use it, otherwise I would go with 80 for the last re-charge. If I were to come into a slightly different coarse grit, I would adjust my process to use it. Size of first grit is not set in stone(no pun intended!!)
Then at some later date I take a batch the Agate/Jasper/Petrified Wood and most times I go straight to a 600 SiC 2nd stage followed by an 80 AO stage followed by polish. In some case I add a 220 SiC stage before the 600 SIC stage. That's really just because I feel like it, no solid reason other than maybe just a bit more fine grinding.
If the Initial load is "flat" run, all slabs/slab-ettes/pendant pre-forms and smalls then I start with 80 SiC and no re-charges for about 10 days. I do add a bit more grit than the Agate/Jasper/Pet Wood run. My thought is that the Flat rocks of this load will breakdown the grit slower and thus grind slower. I always do a 220 SiC stage with the flat run, again more grinding. Then a 600 SiC run followed by a 500 AO prepolish. My feeling is the flat run is the better suited for a 500 AO run due to the slower breakdown rate. After that it's polish run. My finish on Pendant stones and slabs has been really good so I don' change it.
My Arkansas Crystal Quartz runs are treated like Agate/Jasper/Pet Wood initially, then like a Flat run for everything after.
(note; every stage except polish is in the Rotary, and Polish except for the a VLR(very large rock) is in the UV-18)
I do tend to add extra days to various stages if I feel the need. The old wisdom that a few more days here-and there are not really harmful, and are usually helpful to the final product. Runs can also be extended for time constraints and weather, or I just don't feel like doing it today. Extra days can be your friend.
"Beware the Fury of a Patient man"!!
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Post by Bob on Jul 7, 2021 14:46:01 GMT -5
Well, this has been an interesting experience. I agree with everyone who said I could skip 80 and go directly to 220. It has worked, and worked fine for half a year. However, it's not been just as simple as that.
If all I tumbled were my 6 and 12lb barrels, I think it would be just that simple. However, I also tumble 20 and 40lb barrels. Let's take the big 40. When everything is just right, whatever that means, there is no slamming around of rocks and damage that occurs. Maybe 75% of the time it goes so well. Because of that, I've learned to be careful. For instance, putting my favs in it that are almost done with a big rock that still has hard edges on it is asking for trouble. So, the solution for years has been to take those rocks that are "almost done" in rough grind out of the 40lb barrel and do the last week in the 12lb barrel where damage almost never occurs. That's also when I would do the batch in 80 grit. It's been hard mentally switching that run to still be in the 50 or 60 big grit.
Also, with some experimenting, I've learned that anything larger than 80 grit is very touchy to start out with for sensitive materials, such as glass, obs, crystal quartzes, feldspar, sodalite, etc. So I need to still have some 80 on hand for starting those--darn--so I can't eliminate having grit size on hand.
So, since I have to keep some 80 around anyway, I might go back to using 80 in the following way. When I cleaning and sorting a batch from rough grind, if any have a imperfection of say 1/2 mm or less, I know I can take that out in a week in 80 and I might just sort them out to go forward in 80. I've learned at times that another week in 50 or 60 can sometimes grind those a bit more than I prefer and sometimes open up new pits.
But the bottomline is having to have 80 around for those special materials. Are any of you starting those special materials in a larger grit than 80 and having it still work out okay? My experience with those materials suggests to me that grit larger than 80, instead of just wearing down the fractures, can sort of continue them and break off the edges, whereas 80 doesn't seem to do this.
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