rykk
spending too much on rocks
Member since September 2011
Posts: 428
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Post by rykk on Dec 22, 2011 0:22:00 GMT -5
Man, I sure have a lot of questions, eh? :-)
About my favorite agate is the Montana Agate. I collect or cut large-ish (4in +) slabs of it for my collection whenever I can avoid the big money "sharks" on ebay.
I have a few that were already polished and am having a hard time getting that glass like finish consistently on the few that I've tried. They seem to be a really hard rock and might take a lot more time on each grit than the usual 16 - 22 hours I typically run. And maybe a super heavy weight on the, as well?
Has anyone vibe lapped these that might know some tricks like which grits/polish and how long they need to jiggle to lose the matted, "micro-pitted" finish? I do 120/220/600 and then tin oxide polish. Thanks, Rick
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Fossilman
Cave Dweller
Member since January 2009
Posts: 20,681
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Post by Fossilman on Dec 22, 2011 11:53:32 GMT -5
Go to Harmons agates online,this guy is the king of montana agates and will give you pointers on anything you have questions about... www.harmons.net/Contact.htmlI've met and talked this this gentleman several times,he is down to earth and loves to gab...LOL(one hell of a store too)
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Post by johnjsgems on Dec 22, 2011 15:57:27 GMT -5
I can't help with specifics but have talked to and sold grit to a lot of vibe lap people. A real common belief is graded grit makes a difference. Most use 220, 400, and 600 graded grit. Tin oxide is believed best for vibe laps. Common sense tells me the grit breaks down like in a tumbler so a longer run in 600 might help before polish.
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LarryS
freely admits to licking rocks
SoCal desert rats
Member since August 2010
Posts: 781
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Post by LarryS on Dec 23, 2011 0:43:23 GMT -5
I have problems with some agates that I polish on my expando drums if I stop at 600. Found out I needed to run them on a 1200 disk on my Ameritool grinder before CO polish. Does that make since?
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rykk
spending too much on rocks
Member since September 2011
Posts: 428
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Post by rykk on Dec 27, 2011 13:37:05 GMT -5
Larry - yeah, actually that does sound like a decent idea. Maybe a sort of "pre-polish" step. I have an 8" Inland lap and a 1200 and a 3000 disk - I'll give that a shot. Thanks! Rick
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