agatemaggot
Cave Dweller
Member since August 2006
Posts: 2,195
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Post by agatemaggot on Jul 13, 2020 20:47:50 GMT -5
I made the grooved plates out of UHMW plastic about 1 1/2 inches thick, used 90 grit carbide and only ran a couple hours to get the corners from the sawing cuts blended in and the spheres perfectly round. Went over them with a Calipers and if they were within .010 to.015 of perfect I would finish them in the Vibro tumbler. Used Anti-freeze for solution in the Ball mill to keep inside from rusting and had the body of the Mill mounted on springs to adjust how much pressure I had on the Spheres. Sphere blanks should be pretty close to the same size or 1 or 2 will grind like crazy and the rest will just be pushed along for the ride. This is OK if time is no object, just remove the larger spheres when they are round and leave the smaller in to wait there turn.
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jamesp
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Member since October 2012
Posts: 36,154
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Post by jamesp on Jul 14, 2020 7:31:00 GMT -5
I made the grooved plates out of UHMW plastic about 1 1/2 inches thick, used 90 grit carbide and only ran a couple hours to get the corners from the sawing cuts blended in and the spheres perfectly round. Went over them with a Calipers and if they were within .010 to.015 of perfect I would finish them in the Vibro tumbler. Used Anti-freeze for solution in the Ball mill to keep inside from rusting and had the body of the Mill mounted on springs to adjust how much pressure I had on the Spheres. Sphere blanks should be pretty close to the same size or 1 or 2 will grind like crazy and the rest will just be pushed along for the ride. This is OK if time is no object, just remove the larger spheres when they are round and leave the smaller in to wait there turn. Got to put this one on the bucket list agatemaggot. Thanks for the reply. Helps in the confidence department to hear from someone who has completed such a project. I see the need to keep the spheres close in size. Time to round was faster than expected.
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agatemaggot
Cave Dweller
Member since August 2006
Posts: 2,195
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Post by agatemaggot on Jul 14, 2020 8:26:24 GMT -5
Ball mill can put much more pressure on balls than the 3 cup machines because of the power generated by the drill press and the 3 pully system going to the mill itself.
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ataraktos
starting to spend too much on rocks
Member since January 2020
Posts: 140
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Post by ataraktos on Jul 14, 2020 19:10:14 GMT -5
Can I ask what your final polish is? After much trial and error with gassy barrels and trying my lot-o, which also, of course, needed constant minding (little rotary thumler barrels ended up being sufficient, albeit a little messy), I've got my very first batch of bottle glass rolling in polish. Over rocks, I love the fact that you can, relatively easily, get and keep each piece of glass absolutely perfect!
I plan to be patient with this polish stage too but want to make sure I'm not trying to achieve good results with the wrong "tools". Since it's cheap and I have a lot of it, I'm trying AO polish from the Rock Shed. I have some cerium too (but not a lot) that I might try if the AO disappoints. (I'm not sure how I'll tell if the AO disappoints vs operator doesn't know what she's doing. Unless, of course, you use the same Rock Shed AO polish. =)
These look absolutely amazing, btw! The board should change your tag to "master of the rock AND glass domain". I kind of like them with their organic shapes/not perfect spheres, although I'm sure they'd look gorgeous as little marbles, too!
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jamesp
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Member since October 2012
Posts: 36,154
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Post by jamesp on Jul 15, 2020 7:30:41 GMT -5
I prefer perfect shapes with no defects ataraktos too, even if the rocks are not as attractive. And the random 'tumbled' shapes. So the glass works great. Not to mention it is a fast tumble. I have a Lot-O but rarely use it. I modified a Vibrasonic to the point it tumbles glass easily and even if mistakes are made like letting it dry out the glass does not get damaged. But I have done the glass polish step quite a few times in the Lot-O. My secret is the use of sugar as a slurry thickener. The Lot-O is a bit limited to the amount of sugar slurry thickness by it's power, where the Vibrasonic will vibrate glass with a very thick sugar slurry. Vibrasonic vibe recipe(I use 60% polished quartz pea gravel in the Lot-O, and as little as 25% pea gravel in the modded Vibrasonic):: I do 3 days SiC 500, 3 days AO 220, and 8-16 hours Rock Shed polish you mentioned.(preffered) or 3 days SiC 500, 2 days AO 220, 2 days Rock Shed polish. but have used AO 80 instead of AO 220 for 4-5 days. Rock Shed polish is a killer polish for glass. Never tried cerium. In most cases it is not the choice of abrasive that causes failures in getting a polish on glass. It is bruising on a very small micro scale that causes failure. It is extremely difficult to tell the difference if you have micro damage or a problem with the type of abrasive or the length of time run. ETA Restrict the size of your glass to 20 grams. This is important. One big chunk can beat the hell out of all the other glass. Size matters. Hope this hepls.
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ataraktos
starting to spend too much on rocks
Member since January 2020
Posts: 140
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Post by ataraktos on Jul 15, 2020 18:08:48 GMT -5
Thanks so much for the reply! I have a Lot-O but rarely use it. I modified a Vibrasonic to the point it tumbles glass easily and even if mistakes are made like letting it dry out the glass does not get damaged. But I have done the glass polish step quite a few times in the Lot-O. I am trying really hard to love my lot-o. I'm pretty new, still, to tumbling but I have chipping problems in the lot-o, no matter what I've tried, so far. But, sigh, that's another can of worms/box of rocks? ;-) so right now, I'm sticking with rotary for glass. My covington barrels are the world's best gas concentrators too, but I had some thumler barrels. I have managed to keep some pretty thin pieces intact, up to polish. But who knows if their surface was adequately prepared to take a polish. At least now I know, if *you* are using Rock Shed AO, that I've got the right polish in the barrel, whatever else I might be doing wrong! =) My secret is the use of sugar as a slurry thickener. The Lot-O is a bit limited to the amount of sugar slurry thickness by it's power, where the Vibrasonic will vibrate glass with a very thick sugar slurry. Vibrasonic vibe recipe(I use 60% polished quartz pea gravel in the Lot-O, and as little as 25% pea gravel in the modded Vibrasonic):: I do 3 days SiC 500, 3 days AO 220, and 8-16 hours Rock Shed polish you mentioned.(preffered) or 3 days SiC 500, 2 days AO 220, 2 days Rock Shed polish. but have used AO 80 instead of AO 220 for 4-5 days. Rock Shed polish is a killer polish for glass. Never tried cerium. I'm down the gravel rabbit-hole, too! I love the variety over boring ceramics and it seems to hold up much better and cheaper. My 4 year old loves looking at each little one, too. I'm going to want to keep too much of it, after it's polished though. I can already tell. Some pieces are really beautiful, though tiny. And yes, I've been experimenting with sugar in my Lot-o too. But I haven't been able to dampen the motion enough to avoid damage (even of jaspers) while maintaining the proper motion for long. It bogs down after a bit ( Jugglerguy has given some advice and I'm looking for a post about tuning it. Maybe I'm doing something wrong but this whole wooden dowel/glop of glue tuning business can't be but so precise, you know? Not sure I'll work up the nerve to mess with it though. Will see.) In most cases it is not the choice of abrasive that causes failures in getting a polish on glass. It is bruising on a very small micro scale that causes failure. It is extremely difficult to tell the difference if you have micro damage or a problem with the type of abrasive or the length of time run. ETA Restrict the size of your glass to 20 grams. This is important. One big chunk can beat the hell out of all the other glass. Size matters. Hope this hepls. This is helpful, especially the 20 grams note. I'm hoping, the rotary will be a little more forgiving for rolling time, since it generally takes longer, maybe it's not quite as aggressive and will give longer windows. Oh, one question about your recipes above - do you actually "skip back up a grade" when switching from SIC to AO? I mistakenly ordered some 500 SIC, and just decided to do both 500 SIC, followed by 500 AO, mostly to use up the 500 SIC and also because they seem so different, 500 SIC the end of being really abrasive, AO the beginning of polishing/finishing. Then I read that very recommendation (500 SIC -> 500 AO) specifically for glass on a tumbling site.
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,154
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Post by jamesp on Aug 10, 2020 3:23:14 GMT -5
ataraktos I did run polish runs on glass in the Lot-O. But only the polish step. I never succeeded at running the SiC 500 and AO 220 steps in the Lot-O because those 2 steps generate a real thick slurry that my Lot-O did not handle well. It locked up, as if it did not have enough power. I need to use 8-10 tablespoons of sugar for 4 pounds of glass + media for SiC 500, AO 220, AO polish steps. The Lot-O circulation locked up at that rate, the Vibrasonic had no problem circulating the glass/media at that thickness level. My Lot-O has had no modifications. It is as it was when made at the factory. I may not be much help since my success with glass has been from using my modified Vibrasonic. A machine that has been tuned to have shorter vibration travel yet enough power to work with thick slurry. You mentioned SiC 500 and then stepping back to AO 220. SiC and aluminum oxide are very different abrasives. SiC stays sharp by continually shattering into sharp pieces. It cuts well. AO on the other hand slowly rounds off, it is not near as sharp of an abrasive as silicon carbide. It makes smooth surfaces. SiC 500 is many times more aggressive than AO 220. Keeping the glass under 20 grams is for one reason - to reduce impact damage. Big pieces impact with more force than smaller pieces. I struggled for years trying to tumble shape/polish glass. A long road. By applying the mechanics of vibration theory I finally solved the problems. I simply increased the mass(heavier hopper to shorten vibrations), increased the damping in a sort(thicker slurry), and moved the the hopper closer to the excitation source(also shortened the vibrations). If I were you I would try to tumble polish some Mohs 7 agate successfully as a start. If the Lot-O is chipping agate then it will never do glass IMO. Something is wrong. Good luck.
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