jamesp
Cave Dweller
Member since October 2012
Posts: 36,561
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Post by jamesp on Mar 31, 2017 19:09:22 GMT -5
You be the judge. Do your hammer broken agates look this rounded after 26 days ? 18 days, then 8 days. 1.3 cups + 1.3 cups = 2.6 cups total grit per 6 pound barrel, day 8 run was cut short so chunks not depleted. The two big rocks were already rounded. The rest all rough/jagged hammer broken. All Mohs 7 hard agate and wood from Rio Grande. The two big chunks = 1.3 cups. The two middle size chunks after 8 days. The two little chunks after 26 days. SIC GRINDING WHEELS, not the common aluminum oxide wheels. Aluminum oxide worthless for grinding agate. Loose grit at 8 days, loose fresh full sized 50 grit is constantly shedding. Ready for another 3 week run, barrel #1(added 1/2 cup clay this time) And barrel #2: Short 6" PVC barrels Slurry a bit thin IMO, so the 1/2 cup clay to thicken:
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Post by aDave on Mar 31, 2017 20:00:42 GMT -5
Pretty impressive jamesp. I don't know if you mentioned it on another thread, but where would one find such wheels, and it is cost efficient when compared to regular ole grit?
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Post by spiceman on Mar 31, 2017 20:09:22 GMT -5
Two very important questions.
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,561
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Post by jamesp on Mar 31, 2017 20:21:45 GMT -5
Pretty impressive jamesp. I don't know if you mentioned it on another thread, but where would one find such wheels, and it is cost efficient when compared to regular ole grit? I found about 100 pounds of them in an industrial junkyard Dave. They are not cost effective bought new. However, epoxy or some other bonding agent may allow us to make our own 'SiC tablets' out of loose SIC. Cost vs hassle, 18 day runs w/out recharging or opening barrel is pleasant. Only have ~25 pounds left. Need to figure out how to bond some out of loose SiC. May be hard to do...
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Post by aDave on Mar 31, 2017 20:32:06 GMT -5
Pretty impressive jamesp . I don't know if you mentioned it on another thread, but where would one find such wheels, and it is cost efficient when compared to regular ole grit? I found about 100 pounds of them in an industrial junkyard Dave. They are not cost effective bought new. However, epoxy or some other bonding agent may allow us to make our own 'SiC tablets' out of loose SIC. Cost vs hassle, 18 day runs w/out recharging or opening barrel is pleasant. Only have ~25 pounds left. Need to figure out how to bond some out of loose SiC. May be hard to do... Thanks James. I figured "new" was probably out of the question when compared to grit, but I'm glad you addressed it. Obviously, short of figuring out a way to make these, it would be nice to find a consistent source of used wheels. Other than an industrial junkyard, would you find these at metal fab shops, or what? I think the potential "time release" aspect is pretty neat. I didn't have much luck doing a recharge in the coarse grind of my last batch. It just caked at the bottom of the barrel. Now after a week, my grit is non-existent. Unless I get the recharge technique dialed in, my only options are let it run for the full week on worn grit, or do full cleanouts earlier. I'm using old slurry to thicken, so I wouldn't be starting with just water and grit on the cleanouts. That's why this is so intriguing to me. Regards. Dave
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Post by youp50 on Mar 31, 2017 21:16:21 GMT -5
Googling grinding wheel composition brought me to an enlightening dissertation on wheel construction. www.kehih-kogyo.co.jp. (Sorry, I have not figgured out cut and paste on chrome book) The most interesting and available method of binding seems to be the foaming method. Urethane foam, elastic and water resistant properties. Urethane foam is best known to us as "Great Stuff" If you decide to mess with this stuff you need to keep it off your skin. Some people develop a severe allergic reaction to the stuff. It is an accumulative effect, every time you get exposed is one time closer to the ER.
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,561
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Post by jamesp on Apr 1, 2017 6:35:01 GMT -5
Googling grinding wheel composition brought me to an enlightening dissertation on wheel construction. www.kehih-kogyo.co.jp. (Sorry, I have not figgured out cut and paste on chrome book) The most interesting and available method of binding seems to be the foaming method. Urethane foam, elastic and water resistant properties. Urethane foam is best known to us as "Great Stuff" If you decide to mess with this stuff you need to keep it off your skin. Some people develop a severe allergic reaction to the stuff. It is an accumulative effect, every time you get exposed is one time closer to the ER. Never thought about Great Stuff. Yes it is messy but most glues present same issues. However it is the worst lol. But worst may be best. It may be hard to do better than the bonding of a grinding wheel. They are NOT to come apart at high speeds or bodily injury is significant.
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,561
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Post by jamesp on Apr 1, 2017 6:52:19 GMT -5
aDave. No doubt the time release makes for easy and efficient tumbling. At least using SiC bonded so well as these wheels. The trick will be bonding loose grit. The 3 weeks from chunk to marble size works perfect. If they broke down in a week it may be a problem. I have run them at 55 RPM instead of this 30 RPM run. It pretty much doubles grind time. 55 RPM is not so passive though. Kinda fast. SiC grinding wheels have been heavily replaced with much cheaper aluminum oxide. SiC wheels are only used in the most demanding and fastest metal removing operations and at a cost. SiC wheels probably favored for hard metals like a tool and die shop would deal with. Look there. China may be another source. I have priced them out of China, so far they are pricy. Furnace and refractory still a possible source.
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