Deleted
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Post by Deleted on May 1, 2016 15:33:13 GMT -5
jamespI am chomping at the bit to get the quartz purple vibe working. Amplitutude totally adjustable...... Could conceivably get the adjustmants set for different materials. I wonder if setting it up for obsidian would work as well on agate?
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jamesp
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Member since October 2012
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Post by jamesp on May 1, 2016 16:04:15 GMT -5
jamespI am chomping at the bit to get the quartz purple vibe working. Amplitutude totally adjustable...... Could conceivably get the adjustmants set for different materials. I wonder if setting it up for obsidian would work as well on agate? I would be guessing. Vibes beyond my scope of predictability. I will say that short amplitude at 3000/sec can get tricky on a mechanical system. Trickier as the mass increases. Suspicious that the Lot-O engineer had their customers strap their small motor machine to concrete blocks just for a 5 pound capacity to shorten amplitude. A heavy foundation decreases amplitude. But those are basic fundamentals. Larry has created a pivot arrangement that may defy fundamental arrangements. That is one cool design.
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jamesp
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Member since October 2012
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Post by jamesp on May 1, 2016 16:19:57 GMT -5
You can think in terms of simple physics. Kinetic energy of impact = mass X velocity X velocity basically. Square of the velocity, it dominates the impact game. Would you rather get hit by a lineman at 10 mph and 300 pounds or a defensive back at 20 mph and 150 pounds. The back will knock your lights out. So if a rock is traveling 10 inches per vibration vs 1/10 of an inch per vibration at 3000 vibs/sec the velocity at 10 inches of travel is off the chart. Whereas if it only travels 1/10 of an inch at 3000 vibs/sec the velocity of impact is way way less. Obsidian and glass very sensitive to impact pitting, not so much agate. So my Viking is not agreeable to short travels, and it sounds like it. OK for agate, sucks for glass.
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sschus87
starting to shine!
Member since November 2015
Posts: 49
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Post by sschus87 on May 1, 2016 21:03:01 GMT -5
I should add that 1200 is not polish. It's prepolish at best. What is best to use for polish then?
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Post by Jugglerguy on May 1, 2016 21:17:53 GMT -5
I use the Rock Shed's AO polish.
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jamesp
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Member since October 2012
Posts: 36,179
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Post by jamesp on May 2, 2016 5:50:26 GMT -5
I use Rock Shed AO 14,000 polish with Borax if needed.
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Deleted
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Post by Deleted on May 2, 2016 8:01:31 GMT -5
I have used on my spheres, variously, rocksheds ao, Tin Oxide, and cerium oxide. Tin worked on quartz in the tumbler quite well.
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Post by spiceman on May 2, 2016 9:09:12 GMT -5
You know, it almost seems like different people have better luck with different types of polish and different techniques. So what is the answer...keep have good notes and try many different processes. Maybe.
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jamesp
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Member since October 2012
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Post by jamesp on May 2, 2016 11:31:06 GMT -5
You know, it almost seems like different people have better luck with different types of polish and different techniques. So what is the answer...keep have good notes and try many different processes. Maybe. slurry//fill level/speed/barrel size and half a dozen other factors spice take notes or rely on good memory, but do record progress and not-progress
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bills
noticing nice landscape pebbles
Member since March 2016
Posts: 93
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Post by bills on May 11, 2016 23:42:18 GMT -5
Has anyone had the same good results that I have? My next batch is about 3 days away, I am going to try a small amount of polish with the soda to see if it goes any faster. I will report back in a week or so. bii
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Deleted
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Post by Deleted on May 12, 2016 10:56:21 GMT -5
Has anyone had the same good results that I have? My next batch is about 3 days away, I am going to try a small amount of polish with the soda to see if it goes any faster. I will report back in a week or so. bii Before and after pix. Looking forward to it.
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wades
starting to spend too much on rocks
Gottfried Reiche (1667-1734)
Member since February 2006
Posts: 202
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Post by wades on May 12, 2016 16:48:36 GMT -5
I should add that 1200 is not polish. It's prepolish at best. What is best to use for polish then? Most lapidary polishes are metal oxides: tin oxide is usually recommended in older books on the subject, with some writers recommending cerium or chromium oxide for various special purposes. Titanium oxide is sometimes used. Aluminum oxide is maybe the most common these days, having the advantage of being significantly cheaper than alternatives. My first tumbler kit (a Sears Companion, gotten when I was a child almost 50 years ago) came with red rouge polish and it worked OK I guess. Nastily messy though. The details of how polishing works are not as well-understood as you might think. There has been research into exactly what happens in the polishing of optical glass with cerium oxide, and quite a lot of work on chemical-mechanical polishing of silicon wafers (important in the manufacture of integrated circuit chips), but I have not found anything specific to lapidary applications. The results on optical glass polishing are plausibly relevant to understanding lapidary polishing. It is known that material is removed from the surface in optical glass polishing, though the mechanism of this must be different than that of abrasion with silicon carbide, because glass is harder than cerium oxide. The most popular theory seems to be that water interacts with the surface of the glass to form a hydrated layer from which the polishing compound can pull individual molecules by some reversible interaction ( i.e. one that leaves the polish unaffected). This hydration of the glass surface is pH-dependent and also dependent on the precise chemical formulation of the glass: in many cases, polishing time is reduced by raising the pH of the polishing slurry. Adding either borax or baking soda to the slurry would raise the pH. I see that I have not really answered your question. Probably for most purposes, "aluminum oxide 5000 mesh or better." Chromium oxide maybe if you have softer material... I've seen it recommended for lapis, malachite, rhodonite and a few other things. I'm currently using tin because I've got some and feel old-school, but when it's used up I'll go to alumina.
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Post by spiceman on May 12, 2016 21:05:45 GMT -5
OK, maybe a stupid question, but what does Borax do? To the rocks or whatever.
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