jamesp
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Post by jamesp on Dec 16, 2014 10:16:46 GMT -5
Am I reading this ad correctly ? Industrial diamond biz is getting real competitive in China. These look like waste or byproducts. I suppose they cold be sorted by size w/screens by user. Have a hard time understanding the ads. What little I know: Industrial diamonds come in many qualities, quality has big effect on cost. The bigger 20/30/60 grit diamonds are more costly. They may not break down in a tumbler as they can be very tough, but not sure. The price is dropping rapidly due to competitive oversea market. If say 60 grit diamonds could be purchased for 25 cents per gram they may possibly be reused many times for coarse grit ?? That is if they are sharp enough to cut, do not breakdown, and reclaiming them is doable. If they stay 60 grit in size they would cut the rocks constantly at 60 grit rate instead of 60 grit SiC breaking down over a 5-7 day period. Not sure what a cup measurement of diamonds say for a 12 pound tumbler load would weigh. Looks like they weigh 3.36 grams per cc, about 15 cc per tablespoon, 50 grams per tablespoon. At 25 cents per gram that is $12 per tablespoon. Still expensive. 16 tablespoons in a cup, so $190 per cup, ouch. ad: www.aliexpress.com/item/RVD-diamond-dust-FDP-quality/32214439977.htmlTwo bags of 20 grams of 20/25 grit for $38, medium grade that I purchased for possible brazing project:
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jamesp
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Post by jamesp on Dec 16, 2014 10:18:57 GMT -5
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jamesp
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Member since October 2012
Posts: 36,154
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Post by jamesp on Dec 16, 2014 10:24:46 GMT -5
This ad says 30/40 and 60/70 grit for $273.88 for kilo or 2.2 pounds. www.aliexpress.com/item/synthetic-diamond-powder-rvd/1992306833.htmlDensity of lead is about 11 grams per cc. Diamond is 3.3 grams per cc. So lead 3 times more dense. Fluorite is around 3.3 grams per cc. so diamond is not to much heavier than agate. Making reclaim trickier.
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Deleted
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Post by Deleted on Dec 16, 2014 13:36:20 GMT -5
I am not sure what your question is. Those look like diamond to me.
I saw prices as low as $120KG from a super abrasives factory on alibaba, not aliexpress.
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jamesp
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Post by jamesp on Dec 16, 2014 14:15:43 GMT -5
I am not sure what your question is. Those look like diamond to me. I saw prices as low as $120KG from a super abrasives factory on alibaba, not aliexpress. $120/kg, cheaper than I found. I am not sure yet either. But one question would be coarse grit tumble with 60 grit diamonds assuming they could be reclaimed. Do you think they would take the impacts of a rotary tumble w/out shattering ? So they can be reused... And be sharp enough to cut ? With tumbling pressure...
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Deleted
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Post by Deleted on Dec 16, 2014 15:40:27 GMT -5
I am not sure what your question is. Those look like diamond to me. I saw prices as low as $120KG from a super abrasives factory on alibaba, not aliexpress. $120/kg, cheaper than I found. I am not sure yet either. But one question would be coarse grit tumble with 60 grit diamonds assuming they could be reclaimed. Do you think they would take the impacts of a rotary tumble w/out shattering ? So they can be reused... And be sharp enough to cut ? With tumbling pressure... I think if the impact happens at the "incorrect" angle then the stone will cleave. Thus over time every piece will be cleaved into polish. How long? No clue. That why we have you. To take one for the team and experiment...
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jamesp
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Post by jamesp on Dec 16, 2014 19:06:04 GMT -5
$120/kg, cheaper than I found. I am not sure yet either. But one question would be coarse grit tumble with 60 grit diamonds assuming they could be reclaimed. Do you think they would take the impacts of a rotary tumble w/out shattering ? So they can be reused... And be sharp enough to cut ? With tumbling pressure... I think if the impact happens at the "incorrect" angle then the stone will cleave. Thus over time every piece will be cleaved into polish. How long? No clue. That why we have you. To take one for the team and experiment... Will try a braze first. Diamond coated tumbling bowl. hmmm
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Deleted
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Post by Deleted on Dec 16, 2014 19:31:57 GMT -5
I love it.
The forever bowl............. by JamesP
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quartz
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breakin' rocks in the hot sun
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Post by quartz on Dec 16, 2014 23:24:35 GMT -5
Diamond Jim
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Deleted
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Post by Deleted on Dec 17, 2014 2:34:59 GMT -5
I think I see some possible diamond druzzy with HXTAL and a flat stone. Note to self "check with jamesp to see if he will sell a dime bag". Jim
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jamesp
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Post by jamesp on Dec 17, 2014 8:20:52 GMT -5
I think I see some possible diamond druzzy with HXTAL and a flat stone. Note to self "check with jamesp to see if he will sell a dime bag". Jim Those diamonds can be brazed Jim. Diamonds cast in brass cab ? Not sure the cab machine is going to want to put a finish on it....probably best as a druzzy. You think they would give you a buzz ?
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mikeyrocks
starting to shine!
Member since November 2014
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Post by mikeyrocks on Dec 17, 2014 13:36:37 GMT -5
Diamond bort can be had in plain/unprepped, prepped for sintering/brazing, and prepped for resin bonding. I've been using it for years, I first started with recharging copper laps in faceting; then also used them for my beginning cabbing before buying wheels. I've been researching using them with resin and brazing or sintering as well. Two years ago located the information about the bort available prepped/primed specifically for these various applications. I am still working on the methods and materials to both resin bond and sinter diamond for creating or recharging sanding belts and for the sphere cutting cups. Other uses are also for the carving applications. A few big problems in the sintering is obtaining a good mix of powdered metals to mix the bort with. Then there is the matter of heating methods or access to the right kiln. Urethanes seem to be the desired resins for the resin bonding versus the epoxy family, for hardness wear, bonding, etc. All information not readily shared by the industries using it. I don't have any information concerning whether there's a prep being used for the bort for the plating process or not. I am also hearing diamond bort is being used in the ultrasonic drilling applications. This is where I was further informed it is quite affordable in China in bulk. Diamond bort can also be used on wood for charging to do grinding and shaping. Counter to what I initially thought, redwood (soft) seems to be the preferred wood. This was counter to what I would have guessed.... maple and hardwoods. It seems the diamond particles penetrate more easily into the softer wood which also better wraps around the particle to hold it from being thrown off from centrifugal forces. My best price so far for high quality graded bort here in the USA is $450/lb. Same price prepped or unprepped. So for larger particles whether graded or ungraded....$120/kg is very affordable if you need quantity.
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jamesp
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Post by jamesp on Dec 17, 2014 17:11:45 GMT -5
Diamond bort can be had in plain/unprepped, prepped for sintering/brazing, and prepped for resin bonding. I've been using it for years, I first started with recharging copper laps in faceting; then also used them for my beginning cabbing before buying wheels. I've been researching using them with resin and brazing or sintering as well. Two years ago located the information about the bort available prepped/primed specifically for these various applications. I am still working on the methods and materials to both resin bond and sinter diamond for creating or recharging sanding belts and for the sphere cutting cups. Other uses are also for the carving applications. A few big problems in the sintering is obtaining a good mix of powdered metals to mix the bort with. Then there is the matter of heating methods or access to the right kiln. Urethanes seem to be the desired resins for the resin bonding versus the epoxy family, for hardness wear, bonding, etc. All information not readily shared by the industries using it. I don't have any information concerning whether there's a prep being used for the bort for the plating process or not. I am also hearing diamond bort is being used in the ultrasonic drilling applications. This is where I was further informed it is quite affordable in China in bulk. Diamond bort can also be used on wood for charging to do grinding and shaping. Counter to what I initially thought, redwood (soft) seems to be the preferred wood. This was counter to what I would have guessed.... maple and hardwoods. It seems the diamond particles penetrate more easily into the softer wood which also better wraps around the particle to hold it from being thrown off from centrifugal forces. My best price so far for high quality graded bort here in the USA is $450/lb. Same price prepped or unprepped. So for larger particles whether graded or ungraded....$120/kg is very affordable if you need quantity. Thanks for that info mikeyrocks. Real interesting info. Sounds like you have been working with diamonds extensively. Info hard to come by and education helpful on understanding the subject. I was amazed at the abuse diamond segments on cup wheels take when grinding agate. And how cheap they are. I have changed my tumbling rough grind process totally with those wheels. For a couple of years now. I see the word bort refers to diamond powders for industrial abrasives, got that. The segments are wicked, they support the diamonds so well. and also are relatively cheap. China becoming the manufacturing mogul that they are have been streamlining the diamond making process. What I see happening is larger one piece sinterings, like solid sintered 8 inch grinding wheels even for the home shop. Perhaps 1/4 to 1/2 inch thick solid sintered bands to press on aluminum discs for cab wheels... Or thick discs for lap arrangements.
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mikeyrocks
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Member since November 2014
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Post by mikeyrocks on Dec 18, 2014 13:23:48 GMT -5
JBFC....Johnson Brothers is selling 8 inch sintered wheels in the $300 price range with 40 grit priced higher. There appears to be 1/8 or more inch of sintering on the wheel. I have cut 2,000 to 3,000 large cabs on my sintered wheels and there is virtually no sign of wear except for knocking the sharp edge off. That is only because I use the wheel edge like a lathe uses the machine tool to cut steel and I lean into it heavily to get a dome started. I couldn't make such a good wheel on a solid and balanced aluminum core no matter what but I can buy one for about $300 or so; it's a no brainer. I'll make what I can't find at a workable price. I'd prefer to cut instead of make wheels when great ones are reasonable. Sintered versus plated is a discussion for it's own thread sometime when I have the time. Happy cutting and grinding to all. Enjoy!
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jamesp
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Post by jamesp on Dec 20, 2014 0:30:16 GMT -5
JBFC....Johnson Brothers is selling 8 inch sintered wheels in the $300 price range with 40 grit priced higher. There appears to be 1/8 or more inch of sintering on the wheel. I have cut 2,000 to 3,000 large cabs on my sintered wheels and there is virtually no sign of wear except for knocking the sharp edge off. That is only because I use the wheel edge like a lathe uses the machine tool to cut steel and I lean into it heavily to get a dome started. I couldn't make such a good wheel on a solid and balanced aluminum core no matter what but I can buy one for about $300 or so; it's a no brainer. I'll make what I can't find at a workable price. I'd prefer to cut instead of make wheels when great ones are reasonable. Sintered versus plated is a discussion for it's own thread sometime when I have the time. Happy cutting and grinding to all. Enjoy! Interesting about the sinterings Mikey. watching Aliexpress occasionally to keep up with new items and getting education. Too many manufacturers to keep up with. Those products are good news for the lapidary biz. Interesting stuff. Your cab wheel sounds like a winner. I think there will be more to come soon.
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