timloco
has rocks in the head
Member since April 2012
Posts: 545
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Post by timloco on Aug 28, 2014 15:58:53 GMT -5
Has this ever been discussed?
I've finally got enough agate tumbled to do a polishing run in my UV-10 and I was thinking about this. Most burnishing suggestions I've seen suggest a powdered soap of some kind. I talked to an old-timer who's used stuff like powdered spic-n-span even. So I'm not a chemist but I was thinking about what these are - surfactants - compounds that have an opposite charge to whatever it is you're trying to clean up like dirt on laundry or stains on the floor. They attach to the whatever and let the water take it away. So what I think is happening is that the detergents are attaching to the leftover grit and rock dust that are stuck to the tumbled rock and making it easier to wash away. It doesn't make sense to me that the burnish is the rocks rubbing against themselves to smooth the rock itself out,more like rubbing the leftover rock dust and grit off and having the soap prevent it from re-attaching.
There's no doubt in my mind a burnish run makes them look better. I guess the only way to test this would be to hold a rock back from the burnish, wipe it off and just stick in the dishwasher with a rinse aid added maybe and compare.
Thoughts?
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Post by Jugglerguy on Aug 28, 2014 16:56:42 GMT -5
I have wondered the same thing about burnishing. I can't say that I see a difference with or without burnishing. I could just be that I'm doing it wrong. I run my rocks after polish for 2-3 hours with a tablespoon of borax.
From reading that I've done, "burnishing" usually refers to metal. Metal rubbing against metal actually distorts and sort of smears the metal. I'm not sure that's what's happening with rocks though. I think that when people refer to burnishing in tumbling, it may mean just washing the rocks really well after polishing.
I would love to hear others' ideas on this.
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Mark K
Cave Dweller
Member since April 2012
Posts: 2,600
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Post by Mark K on Aug 28, 2014 17:19:45 GMT -5
Well lets say that the burnishing agent does attract the fine particles and traps them. This would be most beneficial as any time any crap and crud comes out of tiny voids in the rock, whether a pinhole or a crack, it would not be allowed to get back in. Often some of my finished tumbles have fine cracks that have trapped the microscopic debris from the processes. If the stone is translucent, it shows. If it is not, I don't really care, but the ones which show are downgraded by this flaw.
Either way, I do it and I am not quite sure it is benign or beneficial, but if it only take a few hours and might help, there is no down side.
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quartz
Cave Dweller
breakin' rocks in the hot sun
Member since February 2010
Posts: 3,341
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Post by quartz on Aug 29, 2014 0:08:24 GMT -5
We routinely run our polished mtl. in a well-padded run of cheap powdered laundry soap mixed to near pancake batter thickness. Run it for 3 or 4 days, and it does help gloss up the rocks. We attribute this to a very slight grittiness of the soap, rubbing friction, and of course, a thorough cleaning. We run mostly pet wood, beach and river agates and jaspers.
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,179
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Post by jamesp on Aug 29, 2014 2:12:41 GMT -5
Lubricating effect may play a role.
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tkvancil
fully equipped rock polisher
Member since September 2011
Posts: 1,546
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Post by tkvancil on Aug 29, 2014 11:40:58 GMT -5
When running my first couple vibe batches I followed the tutorial from here on the board. Did a three hour burnish in borax after the polish phase was done. Held out a piece for comparison. I thought the shine was better. Could be just removal of polish film or something else going on. I'll stick to the practice as it definitely does no harm.
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FLrockhound
spending too much on rocks
Member since July 2014
Posts: 343
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Post by FLrockhound on Aug 29, 2014 15:25:19 GMT -5
After polishing agatetized coral with a lot of pits, I find burnishing with borax is very beneficial as it helps to remove any polish from the tiny pits and hard to clean abnormally shaped agate.
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Steve
has rocks in the head
Member since June 2005
Posts: 506
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Post by Steve on Aug 29, 2014 15:34:07 GMT -5
I've stopped using borax as it kills vegetation. I take a bar of Ivory soap and use a pocket knife to shave it. If you allow the bar to get stale and dry out a bit you get a fine powder, otherwise the shavings work fine. Shave across the short end, it breaks up and crumbles that way.
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Post by Jugglerguy on Aug 29, 2014 15:38:28 GMT -5
So is it burnishing actually burnishing, or should we refer to it as washing?
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SirRoxalot
freely admits to licking rocks
Member since October 2003
Posts: 790
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Post by SirRoxalot on Aug 29, 2014 18:30:09 GMT -5
I think "burnishing", as tumblers do it, would much more accurately be called a final cleaning.
No grit = no polish, unless somebody really wants to contend that there's really fine polishing grit in borax or ivory soap.
Might be a bit of wax or oil in the soap that slightly improves the shine?
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Mark K
Cave Dweller
Member since April 2012
Posts: 2,600
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Post by Mark K on Aug 29, 2014 18:51:29 GMT -5
When I was in 10th grade I got a jolt in the industrial arts class. No real amps, just volts.Hurt like heck. My leg kicked up and nailed the cabinet. The teacher wondered out loud why my leg did that. Quite irritated, I replied "Who gives a XXXX why." He thought this was really funny.
It just did. It just does. We will probably never know why.
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quartz
Cave Dweller
breakin' rocks in the hot sun
Member since February 2010
Posts: 3,341
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Post by quartz on Aug 29, 2014 22:50:28 GMT -5
Well said Mark.
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Post by braders on Aug 30, 2014 20:37:39 GMT -5
Well im at that stage now in my tumble, and have never done a run without the final burnish ..so heck lets just see All else fails throw um back in for another shake !
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carloscinco
fully equipped rock polisher
Member since July 2008
Posts: 1,639
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Post by carloscinco on Aug 30, 2014 20:59:23 GMT -5
No scientific proof here, just observation. Rocks coming out of the final polish can sometimes have a haze in spots that burnishing improves. I use Dawn dish soap for 12 hours. No negative effects from burnishing as far as I can tell which is no selling point but since it helps remove sludge from vugs and druzy pockets it is worth it to me.
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mandarcus
off to a rocking start
Member since September 2014
Posts: 2
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Post by mandarcus on Sept 4, 2014 19:16:22 GMT -5
Hello, folks: I just ran two 3-pound barrels of agate for a 24-hour borax burnish (first time I've tried burnishing), and now there are many little white spots in the pits that weren't there following any of the other steps. It appears the borax itself has gotten caught in the pits. What might I have done wrong, and how would you recommend I salvage the otherwise-gorgeous stones? Thanks!
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Post by braders on Sept 4, 2014 19:33:44 GMT -5
Hello, folks: I just ran two 3-pound barrels of agate for a 24-hour borax burnish (first time I've tried burnishing), and now there are many little white spots in the pits that weren't there following any of the other steps. It appears the borax itself has gotten caught in the pits. What might I have done wrong, and how would you recommend I salvage the otherwise-gorgeous stones? Thanks! Run them longer in fresh water it didnt dissolve is all ...possibly ya put way to much in as well ?
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Post by Jugglerguy on Sept 4, 2014 20:24:22 GMT -5
Are the pits new after burnishing or just the white stuff in the pits? I've never had burnishing cause pits. I also have never had pits in something that I burnished. All pits are removed in the first tumbling step for me. If there are pits, it goes back in rough grind for another week.
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mandarcus
off to a rocking start
Member since September 2014
Posts: 2
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Post by mandarcus on Sept 5, 2014 10:42:03 GMT -5
Thanks for your responses! I'm running them again with MUCH less borax, and we'll see what happens. If there's still any residual white spots, I'll try a water-only tumble. These stones came from Agate Beach on Lopez Island, Washington, and some of them just seem to retain little pits, even after 2 weeks in both coarse and fine grit. How long would you recommend for the burnishing run in general?
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Post by Jugglerguy on Sept 5, 2014 11:56:22 GMT -5
I run many of my rocks for 10 weeks or even longer in course grit. I only take them out when all the pits are gone. There are, however, some rocks that are sort of porous all the way through, so that when you get rid of surface pits, you end up exposing more pits. Those rocks will never be pit free.
I do my burnishes for 2-3 hours, but it's the part of tumbling that I understand the least. I still think it is simply a wash, but I'm not sure.
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Post by Drummond Island Rocks on Sept 5, 2014 13:21:16 GMT -5
I use two tablespoons of borax for a couple hours when I burnish with the lot-o vibe tumbler. Back when I used a rotary I burnished overnight with two tablespoons in a 3 pound barrel. I do use extra water when burnishing to keep it from turning into a paste. I try to tumble in stage one till the rocks are as good as I think is possible. Some rocks will never be perfect but those just get some extra attention at each wash out. Here is an example tumble of agates that ran in rough grit for 18 weeks. The last photo shows what the rocks looked like before I started. Thank goodness all rocks do not take this long. forum.rocktumblinghobby.com/thread/66971/good-pic-heavyChuck
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