EricD
Cave Dweller
High in the Mountains
Member since November 2019
Posts: 1,142
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Post by EricD on Aug 1, 2020 19:46:19 GMT -5
With such wide variety I guess it's important to have a supplier that knows much more than I do about the different types and grades, and their performance in the end use(s) they are advertised for. A neighbor worked as a district salesman for Washington Mills. He rarely had samples of silicon carbide but he was always loaded up with a plethora of 5 to 10 pound cans of aluminum oxide samples from AO 22 to AO 50,000. Colors were browns, white, grays and black.. Some were for military applications, some for industry, some for product mixes. Some of it was $2/pound and some $50/ounce. I ran it thru the tumblers over the years only respecting the grit size and never noticed much difference in them other than they acted like the grit size they were listed as. I know buy AO 500 and 14,000 from the Shed and the others(mostly AO 220) from the Abrasive Armory on EBAY. The Abrasive Armory's AO is always white. The Abrasive Armory is the place to go for abrasives. I have never received anything I didn't order and the service/knowledge/product is amazing.
You should have noticed a marked difference in grits of different color since some rounds and others fracture. Brown AO matters.
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,154
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Post by jamesp on Aug 2, 2020 5:10:49 GMT -5
A neighbor worked as a district salesman for Washington Mills. He rarely had samples of silicon carbide but he was always loaded up with a plethora of 5 to 10 pound cans of aluminum oxide samples from AO 22 to AO 50,000. Colors were browns, white, grays and black.. Some were for military applications, some for industry, some for product mixes. Some of it was $2/pound and some $50/ounce. I ran it thru the tumblers over the years only respecting the grit size and never noticed much difference in them other than they acted like the grit size they were listed as. I know buy AO 500 and 14,000 from the Shed and the others(mostly AO 220) from the Abrasive Armory on EBAY. The Abrasive Armory's AO is always white. The Abrasive Armory is the place to go for abrasives. I have never received anything I didn't order and the service/knowledge/product is amazing. You should have noticed a marked difference in grits of different color since some rounds and others fracture. Brown AO matters. Is there a place I can purchase some ? I'd give it a go on fossil coral. I picked up a 5 gallon bucket of brown AO 46 sand blasting grade for a song at an industrial junkyard. I have used it over the years for tumbling the rust off of 1.5" sch 10 fire pit legs and removing the limestone skin off of fossilized coral. But never in a rock tumbling step. I believe silicon carbide is the industry standard for fast metal removal but is a bit too costly to fuse safely for Walmart to sell as bench grinder wheels.
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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 Aug 2, 2020 18:56:22 GMT -5
The Abrasive Armory is the place to go for abrasives. I have never received anything I didn't order and the service/knowledge/product is amazing. You should have noticed a marked difference in grits of different color since some rounds and others fracture. Brown AO matters. Is there a place I can purchase some ? I'd give it a go on fossil coral. I picked up a 5 gallon bucket of brown AO 46 sand blasting grade for a song at an industrial junkyard. I have used it over the years for tumbling the rust off of 1.5" sch 10 fire pit legs and removing the limestone skin off of fossilized coral. But never in a rock tumbling step. I believe silicon carbide is the industry standard for fast metal removal but is a bit too costly to fuse safely for Walmart to sell as bench grinder wheels. I haven't seen any brown aluminum oxide for sale in the usual grit places. I assume because SiC and white AlOx outperform it? Don't know for sure.
From Washington Mills:
"Brown fused alumina is widely used as a raw material in refractories, ceramics shapes, grinding wheels, sandpaper, blasting media, metal preparation, laminates, coatings, lapping, polishing, grinding and hundreds of other applications." I agree SiC works wonders at removing rock. The only thing that seems to work better for that purpose seems to be diamond.
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,154
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Post by jamesp on Aug 2, 2020 21:02:45 GMT -5
Apparently silicon carbide is the best for the buck for removing rock. Synthetic diamond keeps dropping in price. It would be nice to use it.
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Post by Mel on Aug 30, 2020 14:15:24 GMT -5
jamesp - that agate is amazing!!! For my next batch I'm using 1200 white aluminum oxide; am curious how it performs compared to the titanium dioxide I've used in the last year or two. Nicer on the wallet at the very least. I would not think that different sizes of AO are going to affect the sheen/polish of a finished rock that much, unless you're looking at it under a magnifying glass.
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