jamesp
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Post by jamesp on Feb 25, 2015 9:55:54 GMT -5
Again, starting from coarse grind in the rotary to one day in garnets in the vibe. Added polish, but it did not help much. Pulled these three for inspection
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Fossilman
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Post by Fossilman on Feb 25, 2015 10:20:58 GMT -5
Have a ways to go huh.............
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39don
starting to spend too much on rocks
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Post by 39don on Feb 25, 2015 10:47:04 GMT -5
It is looking like the garnets are over working the soft areas of the corals.
39don
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jamesp
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Post by jamesp on Feb 25, 2015 11:58:19 GMT -5
It is looking like the garnets are over working the soft areas of the corals. 39don Yes Don, basically undercutting, which is actually what I want on these. That white husk is hard too. And they were run in the rotary with SiC 30/60 till the colored areas were exposed for a month or two. The effect of leaving the white 'bark' is a target. No doubt those garnets will seek and destroy soft areas when running in the vibe. I let them dry out twice on past occasions, those garnets sat in one place and drilled holes in the rocks when all froze up LOL. I never knew that high specific gravity of media had such an impact in a vibe grinding efficiency. Reading about super high SG media material like Zirconia @ SG 6. Very expensive but cadillac media. Curious what ceramic media is sold at rock shops. It ain't zirconia, too expensive. I wanted to ask you if you used to use media in the ceramic resistor biz.
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jamesp
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Post by jamesp on Feb 25, 2015 12:01:00 GMT -5
Have a ways to go huh............. That was the desired effect Michael, to leave some of the white coating. And polish the areas w/color. That way it is obvious that it is coral. The two on the right were baked, the white one not heated.
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39don
starting to spend too much on rocks
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Post by 39don on Feb 25, 2015 18:29:09 GMT -5
It is looking like the garnets are over working the soft areas of the corals. 39don Yes Don, basically undercutting, which is actually what I want on these. That white husk is hard too. And they were run in the rotary with SiC 30/60 till the colored areas were exposed for a month or two. The effect of leaving the white 'bark' is a target. No doubt those garnets will seek and destroy soft areas when running in the vibe. I let them dry out twice on past occasions, those garnets sat in one place and drilled holes in the rocks when all froze up LOL. I never knew that high specific gravity of media had such an impact in a vibe grinding efficiency. Reading about super high SG media material like Zirconia @ SG 6. Very expensive but cadillac media. Curious what ceramic media is sold at rock shops. It ain't zirconia, too expensive. I wanted to ask you if you used to use media in the ceramic resistor biz. Yes, we used a lot of our own ceramic materials as tumbling media. We even had various configurations and material make-up too. I wished I have saved a lot of the throw away stuff I could have been using nowadays. As far as the resister business it was by far easier and cheaper to prefire the ceramic which made it harder but not as hard as the finished firing would do. We tumbled it with a slurry of AO only to achieve a specified radius on the sharp ends of the small pins or rods. 39don
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jamesp
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Post by jamesp on Feb 25, 2015 19:04:08 GMT -5
Interesting 39don. Guess you had some serious tumblers at the factory. From what I read, media cost is costly. Having the ability to fire your own was a big money saver. they have medias made out of some really hard material. Was surprised at the different materials used.
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39don
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Post by 39don on Feb 26, 2015 0:16:53 GMT -5
Interesting 39don. Guess you had some serious tumblers at the factory. From what I read, media cost is costly. Having the ability to fire your own was a big money saver. they have medias made out of some really hard material. Was surprised at the different materials used. A little more detail of the ceramic manufacturing was we had 50lbs of AO, I believe it was called AO1287, which was a coarse AO as our standard raw material. According to plant needs a build slip was started to manufacture a certain material to make a desired ceramic product. We referred it as a "body" such as #614 and which was a 96% alumina. The necessary raw materials were pulled and processed in large ball mills. These ball mills were like a rotary tumbler but had either solid alumina balls or 2" Belgium beach agates and were 10' to 12'in diameter and 15' to 20'in length to pulverize the AO power to a specific particle size. Once the particle size had been achieved they would pump the slip to a spray dryer. The spray dryer had a rotating head rotating up to 10,000 rpm. The slip sprayed out of the head into a heated cyclone chamber of 30' to 40' diameter and 50' to 60' tall. The slip was dried in the air and fell to the bottom discharge chute into heavy plastic bags inside 50gal barrels. Note, a tablespoon of a incorrect material accidentally placed in the wrong barrel would contaminate the material remaining, big $ loss. The materials made by body prep were sent to manufacturing for further processing ie., extrusion, pressing, injecting molding, isostatic pressing and tape casting. The materials ranged from steatites to high purity very fine grain 99% alumina's. Items manufactured and sold by the plant are too numerous to list but a few were fishing rod eyelets, made only for Marlin fishing championships, electrical insulators for hair dryers, thread guides for the textile industry, tape guides for recording machines and tape players, substrates for microchips, material for dental crowns, tips and covers for tig and mig welders etc........ When I first started in the machining dept. I hand dressed a alumina grinding wheel to make the ceramic inserts for a subsidiary VP's, with 3M, wood golf clubs. I made 4 sets for him and when he visited our plant he would come around and smile but never said anything. I believe he had a company named Eagle to adapt them to their woods. I'm not a golfer but those inserts are not flat and have a compound radius on the face with 6 to 8 grooves, .018" wide and .018" deep to grip the ball to get a reverse spin on it. You could really get happy with ball mills like we had till it came time to pay for the loads or for the mills themselves. It seems like the smallest mill was a 50lb and the largest a 10,000lb. 39don
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jamesp
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Post by jamesp on Feb 26, 2015 6:29:58 GMT -5
Uh, that is taking tumbling to a new level 39don. I noticed alumina and agate balls when researching media. They cost a bunch. Also noticed Alum Ox is sold in a range of sizes under one grit designation. After reading what you go thru to work with these ceramics it is starting to make sense. The golf club inserts sure sound like rich executives getting fringe benefits. hmmm Sounds like a real involved process. Most would never guess how much cost and effort goes into making the aluminum oxide abrasive alone. Am happy to know that there is no 10,000 pound rotary tumblers to look after, with 2 inch alumina balls to purchase to fill the beast. And agate balls from Belgium ?? Must be some solid agate and able to be quarried or collected some how. Perhaps beach rounded to start ? Got to look that one up. Found Brazilian agate balls, now where are the sphere machines to mass produce these agate balls ? @shotgunner ?? Brazilian agates are close to round, maybe that expedites making spheres from them. Ball mill in operation, the folly of not filling your tumbler to 3/4 full !! Reminds me of my first load of obsidian. Real ball mill tumbler with glass window and demonic German serial killer soundtrack(start video at 1 minute)
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quartz
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Post by quartz on Feb 27, 2015 0:00:11 GMT -5
That sure shows why it's important to keep a tumbler close to full. Poor camel.
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jamesp
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Post by jamesp on Feb 27, 2015 4:35:29 GMT -5
That sure shows why it's important to keep a tumbler close to full. Poor camel. Yes, rotary tumbler turned crusher. After months of experiments with softer material the 'ball mill' effect has been an issue. Getting back to coral, Rio Grande agates, Mcdermitt wood and other agates has been a relief. They are the opposite. Slow to coarse grind and a easy to polish, almost no concern about bruising and under cutting. I kept speeding up the rotaries and going to coarser grits with agates till the best speeds and grit size was found to shorten coarse grind. That all worked out well, ran them fast(6 inch @ 55 RPM) for years with great results. Worry free tumbling. Change SiC 30/60 coarse grit out every 4-5 days about 8-10 times. Sometimes longer. After 50-70 days they were well rounded and ready for 1 week runs in 220, 500 and polish @ 30 RPM. Never failed. routine The only difference now is running all 4 barrels at 55 RPM and feeding the vibe for finishing. And it sits waiting for the 4 roughing barrels.
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