jamesp
Cave Dweller
Member since October 2012
Posts: 36,275
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Post by jamesp on Oct 16, 2016 14:54:54 GMT -5
These need to be run again in the rotary with out the big rock to refinish better before dropping in vibe. They were removed from the rotary at various stages of SiC 30 and would benefit a week roll in 30 to break the grit down to 300-400. As they are out of the vibe and AO 80, ready for AO 500. They have 3 weeks on them in coarse grind. Mostly coral Rio moss Rio wood Rio conglomerate Heat treated coral closer ins Very depressed baby tree frog. Perhaps in need of Prozac ?
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Post by oregon on Oct 16, 2016 17:06:07 GMT -5
Seems like the big rock really grinds things, but might be a bit too aggressive (if your goal is just tumbling the entire batch as efficiently/quickly as possible rather than just polishing the large rock). So I've always wondered if just some large steel ball bearings would speed things along, Denser than most rock, should be hard steel for bearings, and present smooth surfaces. other than that, what about adding a 1-2lb excersize dumbbell weight that is vinyl/rubber/neoprene clad - not sure of the longevity, but? thoughts? Thanks for the experiments.
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,275
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Post by jamesp on Oct 16, 2016 17:43:53 GMT -5
Seems like the big rock really grinds things, but might be a bit to aggressive (if your goal is just tumbling the entire batch as efficiently/quickly as possible rather than just polishing the large rock). So I've always wondered if just some large steel ball bearings would speed things along, Denser than most rock, should be hard steel for bearings, and present smooth surfaces. other than that, what about adding a 1-2lb excersize dumbbell weight that is vinyl/rubber/neoprene clad - not sure of the longevity, but? thoughts? Thanks for the experiments. My thoughts oregon- reap a big rock out of the deal. Use it for your 'grinder'. Even if you have to run the big rock separately one grind cycle with small media afterwards. Same with the small rocks, run them one grind cycle without the big rock to remove any frost that may have occurred. I kept 3 buckets of rocks out. 1-2 inch, 1 inch and 1/2 inch. All agates, nice pretty tumble material, as media. Used the bigger ones if the big rock had no bruises, the middle size for slight bruising, and the smallest if the big rock was getting hammered. The range of sizes did the trick. The 1/2 inch stuff made a very gentle tumble for the big rock. But the grit broke down a good bit slower and grind slowed as you would expect. I did pretty well with a 2 pound obsidian as an early test in the rotary and had no bruises using 1 inch media. That surprised me. I dried it out in the sun for hours and could not see a bruise. That was telling. I moved it to my Vibrasonic and only got a matte finish, which is the only finish I get on obsidian be it small or large tumbles in that vibe. Unlike a Lot-O, that does obsidian well. Now a rubber coated hunk of high density metal may solve all problems of bruising. That is a great idea. And should speed your grind too. Rubber/neoprene resistes abrasives. That is how tomb stones are engraved. They spray liquid rubber on the tomb stone. Cut out letters and then sand blast it with a very powerful compressor. Letters blasted like 3/8" into tomb stone. The sand bounces of the rubber like it was diamond. No doubt though, the big weight very much speeds up the grind. Most of the Mohs 7 stuff had no bruising even at 55 RPM which is flying with a 2 pound knocker in the barrel. So if you stick to agate and pet wood it should be fine. Thanks for the input. It is a very different concept adding that weight in the barrel.
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Post by oregon on Oct 16, 2016 18:11:54 GMT -5
yeah, I remember the first time I sandblasted glass, they said to cut a mask out of masking tape with an exacto knife. I thought yeah right, this thing peels rust no problem, how is the masking tape ever going to hold up, but it does. I imagine it's the same on a small scale, that the sand bounces off the tape, elastic vs inelastic collisions or such... So what about a single big rock in larger 12-15lb barrels? any tests there?
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Post by orrum on Oct 16, 2016 20:41:12 GMT -5
I like that black edge corsl!!
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Post by Garage Rocker on Oct 16, 2016 21:37:28 GMT -5
I'm a fan of that black and orange coral too. Good looking stuff James. Gonna try the big rock method someday.
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Post by MrMike on Oct 17, 2016 6:12:02 GMT -5
Very cool stuff jamesp. I bet the frog was scared it would be mistaken for a pretty green rock...
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,275
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Post by jamesp on Oct 17, 2016 6:17:27 GMT -5
Very cool stuff jamesp. I bet the frog was scared it would be mistaken for a pretty green rock... Morning cool had him drawn up. Or he saw me ugly and shriveled up:)
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,275
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Post by jamesp on Oct 17, 2016 6:33:41 GMT -5
yeah, I remember the first time I sandblasted glass, they said to cut a mask out of masking tape with an exacto knife. I thought yeah right, this thing peels rust no problem, how is the masking tape ever going to hold up, but it does. I imagine it's the same on a small scale, that the sand bounces off the tape, elastic vs inelastic collisions or such... So what about a single big rock in larger 12-15lb barrels? any tests there? yes, inelastic collisions seem to tame I have done a bunch of 7-11 ounce rocks in both 6 and 8 inch PVC barrels together. The 8 inch barrels caused bruises at same surface speed. And after 11 ounces bruise happen easily. Better to do bigger by themselves. But, doing a single 1-2 pound or bigger in an 18 inch wide 6 inch barrel is better than a 10 inch wide 6 inch barrel. Short barrel seems to make the big rock roll rough. Looks as if large barrel diameter may cause potential for harder banging.
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,275
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Post by jamesp on Oct 17, 2016 6:40:31 GMT -5
I'm a fan of that black and orange coral too. Good looking stuff James. Gonna try the big rock method someday. I like that black edge corsl!! They stuck a little NO TRESPASSING sign up on a little creek that yielded the finest black edge. Note Bengal tiger upper left(kidding)
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Fossilman
Cave Dweller
Member since January 2009
Posts: 20,690
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Post by Fossilman on Oct 17, 2016 9:49:54 GMT -5
Nice tumbles James,the color of many colors too... That Rio kicks butt too... Going to have to hit Mel up for some small Rios too......SWEET!!!
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stonedape
starting to spend too much on rocks
Member since July 2016
Posts: 116
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Post by stonedape on Oct 20, 2016 12:24:13 GMT -5
Lots of great looking rocks!!
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