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What could be viewed, by the successful pros here, as the most accepted burnish run time for rotary tumbling after polishing?
I have not paid much attention to this. It seems that I hardly can detect any improvement in burnish shine after a half-day, so tend to start a burnish run around dinner time and then get it out at lunch time the next day. I used to do it for a full day, or even to full 3 days. But I've never really analyzed carefully if much improvement over time. I'm not even sure how one would assess. If a rock is very shiny, how can you tell if it's even shinier later? Try to read, with a magnifying glass, reflected print from a tiny Bible?
This isn't about any particular material, but let's just say about mixed loads of commonly tumbled materials.
My reason for asking is I'm about to add a burnish test to the big polish comparison test I did, and for it to be done properly I will need to time the burnish runs and make them all the same.
Post by hypodactylus on Feb 14, 2023 13:03:59 GMT -5
Feel free to disagree, but most of what I hear people call 'burnishing' in this hobby should probably just be called 'cleaning'.
I personally run a final stage with a scoop of powdered ivory soap, and a normal amount of water. I keep the same rocks and ceramic media together, but I wash out all the polish/slurry. This stage usually runs for about an hour, but only because I am usually washing out other barrels while I wait. Thirty minutes or less would probably have the same affect.
I do this for cleaning purposes. It removes residue often left behind by the polish slurry and possibly my hard water. I noticed a difference, so I keep doing it. I do not consider this burnishing.
When I hear of people running a soap/borax stage for a day or more, I wonder why. I can't imagine it benefits anything to do such a long cleaning stage. If anything, I would expect it to dull the shine achieved by the polish.
I think burnishing is a real thing, separate from cleaning. I live in an area where water leaves no residue, not that I know whether than means hard or soft water. There have been times when I have rinsed and washed rocks coming out of polish--a lot. But yet gasped with delight when I saw how much shinier they came out of burnishing. If you take a 10x hand lends to the surface, you will see an actual difference.
In the beginning, I used to do a polish run, then a rinse, then a burnish run and I noticed that the burnish run would sometimes contain water that is a little bit dirty, hardly at all, but not quite clear. Then I switched to a 2 polish run. Week 1 in polish, then week 2 in polish used only for week 2 after a thorough rinse. That week 1 polish becomes dirtier over time, but the week 2 polish hardly changes at all. And since switching to 2 week polish method, the water after burnish has always remained clear.
My reason for doing that is I suspected that rinsing pre-polish, no matter how well, could still enable 1 or more grains of 1,000 grit to enter polish, which isn't good. I have never done it, but I know some tumblers who go to the trouble of tumbling rocks in a soapy solution for a few hours between pre-polish and polish to get them extra clean before polish.
Some old timers have told me how with some materials, burnishing for a week or more can improve the shine. I've also been told that burnishing too long can go past a sweet spot and then become damaging to shine (obsidian).
When I first got into tumbling, it was from a guy who was also an artist. He said after 30+ years of tumbling he had come to regard it as an art form which I thought was odd. But now that I've done it some myself, with the zillions of variables involved, I tend to agree with him.
He told me the soap's function isn't to clean, but to create a slimy mess such that the rocks slipped all over each other--almost frictionless--and increased the "amorphous surface effect" that increase shine.
Talking about this gives me ideas about a special test just to test burnishing methods, but that would need to be done on one uniform material. There could be a control which is water only.
I usually make a burnish run after completing a batch in Polish. For me it's about cleaning which I do with shaved Ivory Bar soap and a table spoon or two of Borax. The burnish runs are usually about 4 or 5 hours. On occasion I have run longer however that's more a could not get to cleanout for a longer period. I have pulled a polished slab out of the batch, gave it a good rinse and set aside. Meanwhile run the adjacent slab(same rock) in the batch through burnishing. Afterward a comparison of the two slabs does not seem to make any noticeable difference. I suppose if I had some hi-tech laser enabled spectrometer, maybe that would reveal some slight difference in the two surfaces. My hope is that the burnish run does help to remove any trapped slurry/polish. It may remove some, but it does not remove all.
Take my opinion with a grain of salt as I have dis-continued any soap runs between stages with burnishing after polish being the only one.
Henry
There are more things in heaven and earth, Horatio, Than are dreamt of in your philosophy.
You always have good guidance so I don't think I will ever take what you have to say with only a grain of salt.
I'm tempted to think that if burnishing is only cleaning, that there would be easy ways to test this. Random thoughts...if the water remains crystal clear, but yet the shine improves, surely the rocks didn't get any cleaner?
It would also not be very difficult to take a batch of really good, durable, well polish rocks, like some rounded, no defect jaspers of which I have plenty, burnish for 0 mins, do 5 mins more, do XYZ mins more, etc. until eventually working up to adding several days more. I guess a few of the same rocks from each of those steps would need be to be placed in a cradle and photographed in exactly the same way with all background and overhead lighting exactly the same. This could be done with both soapy water and with plain water.
It's kind of ridiculous in a way how we pursue this perfect shine thing. But it makes it fun. We are all crazy.
We do a lot of petrified wood from the Northwest and have found a week of burnish after a thorough post polish cleaning gives our stuff a better luster. This doesn't hold as well with everything, beach and river agates don't improve as much. For my burnish mix I stir up cheap dry laundry soap in water to get a near thin pancake batter viscosity and I pad the load with chunks of cut up leather scraps in the 1/2 to 1" size range, about 75% rock and 25% leather.This in a large barrel, smaller chunks for smaller, say 12 pound, barrels. It is a little messy but works for us, and I do reuse the mix.
We do a lot of petrified wood from the Northwest and have found a week of burnish after a thorough post polish cleaning gives our stuff a better luster. This doesn't hold as well with everything, beach and river agates don't improve as much. For my burnish mix I stir up cheap dry laundry soap in water to get a near thin pancake batter viscosity and I pad the load with chunks of cut up leather scraps in the 1/2 to 1" size range, about 75% rock and 25% leather.This in a large barrel, smaller chunks for smaller, say 12 pound, barrels. It is a little messy but works for us, and I do reuse the mix.
In a manner, with the leather pieces included with the soap, you have a hybrid burnish(washing)/buffing process. The use of leather even with out any polish should be able to increase the polish factor. I do like the idea and it's related to another I have for future testing. And the list just gets longer!!
There are more things in heaven and earth, Horatio, Than are dreamt of in your philosophy.
"...another I have for future testing. And the list just gets longer!!"
Boy do I know that feeling.
Unfortunately, we are not young people. When I walked around Quartzite, I started mentally noting the general age of both the vendors and the customers. 60? 70? 80? A few hours later, I ran into a booth in which a young lady of maybe 30 at the most was home schooling two young children right there in the booth. I was so happy to see this we talked for a while. She knows how someone that age is rare.
They look great when taken out of polish and rinsed in hot water. But then, back in the drum they go, boraxed and ivoried in hot water, and in an hour or 2 that water sure comes out awfully gray. Some of this no doubt is coming off the drum itself (itself a good thing) but I am sure plenty of it comes off the rocks too. So I will continue this end-practice. Sometimes I do it twice.
I never believed in burnishing, until I tried it. I have very hard water ( I swear I could tumble my water it is so hard lol) If I let my rocks dry naturally (air dry) they will have a very slight haze on them. They also feel "grip-ey" I guess (not slippery). If I rub them with a paper towel vigorously they will become slippery and a slight bit shinier. I tried burnishing them just for giggles. Well not only did I notice a better shine, I also noticed I didn't have to polish my rocks with a paper towel! I played around with times and found that 18 to 24 hours was about right (longer doesn't improve things). 12 hours isn't enough. I use Borax (never tried anything else). Now in the vibe I have been using a dishsoap wash between stages, with a final burnish with borax for about 6 hours and I am super pleased with the results. If you have hard water I highly recommend a burnish with borax.
I can't tell if thats some Gneiss Schist, or that Schist is Gneiss. All I know is don't take it for Granite
Chris Sikk, I don't use split leather, it will turn to shreds in a short time, full thickness lasts a very long time, can't say I've worn any out, yes I do reuse it.
In the thread titled "20lb batch (mostly chert) finished 12/14/2022 w photos" I have included post burnish shots (just finished doing so) for all the rocks in the batch that were also photographed before burnish. In some cases I think the improvement can be seen in the photo, but mostly I think the photos look the same. But even my wife could see that the batch of rocks were more shiny after burnish.
Some have mentioned that they think there is a chance that burnish may not truly change the rock other than simply remove leftover polish. I find this hard to swallow. Tin oxide is bright white, so the pour off water from my 2nd week in tin oxide is of course white like milk. I never let the rocks dry. I pour off the tin oxide slurry, then pour more water over the rocks in the barrel, then pour off again, and repeat this several times. Then the last time the rocks are under water but still in the barrel. Then I grab them and left them out into a large plastic bowl containing water and they go under the surface. Then I carry into my sink, and rinse and rinse 4-5 times. Even though this rinse water is clear, I do it anyway just in case ANYTHING, even a particle of something on my hand or from my head, got into the bowl.
Then I store these rocks dry in a plastic container until they are ready to burnish which might be hours or weeks later.
Then, I prepare the burnish barrel with soap and some water. I take the stored rocks, put them all in a bowl of water, and lift them from the water into the burnish barrel. I do this in case any dust from the air is on the rocks. Then I do the burnish run. Before burnish in other words, those rocks look very clean to me.
Some rocks are black. They seem no blacker after burnish, just shinier. It seems if burnish removed tin oxide polish residue, that a black rock would not be as black before burnish. Anyway, this is my bias and speculation.
Post by hypodactylus on Apr 19, 2023 11:10:45 GMT -5
To play the contrarian; if you think there is no residue on your rocks, why do you add soap to your 'burnish' stage?
I know I often have residue on my rocks after the polish stage, no matter how well I rinse them. If I rub them rapidly on a cloth, I can clearly see the difference in the shine. Since I don't want to rub them all manually, I do my hour long 'cleaning' tumble with 'pure' soap and water to get the same/similar result.
I once tumbled some rough stage 1 rocks without grit to see what would happen. I left them tumbling for a week. I was surprised by how shiny the rocks were; it was highly unexpected. Granted, they weren't 'polish' shiny, but they had a light shine. I have since come to consider this to be true burnishing.
I’ve accidentally forgotten to add coarse grit to the big tumblers a couple times. I’m amazed how shiny the rocks get without any polish. This in my mind is burnishing. There is usually quite a bit of impact damage too, especially if there are some larger rocks in the batch. I’ve heard that burnishing is actually “smearing” the surface molecules of silica, smoothing them at a microscopic level. I don’t usually run a burnish cycle, just cleaning with soap.
I too have tried to read and understand burnishing and what happens and noticed that it's mentioned at times that an amorphous layers is formed a few molecules thick.
As to the use of soap for it, I guess I was just following recommendations in the tumbling literature and also an old timer that taught tumbling to me. My speculation was that it's some kind of slippery lubricant that keeps the rocks sliding all over each other. Maybe you are right in that it's soap for a reason to clean the rocks too--cleaning in this case I guess could only mean cleaning of residual polish.
Never have I tried that rubbing on a cloth test after two weeks in polish and before burnish. I see your point and will remember to try it!
I have recently started using a cheap ultrasonic cleaner after the polish stage. I have noticed that no matter how well I rinse my rocks, the water in the ultrasonic will be cloudy when I am done. This is without running a "burnish stage". At some point, I would like to run a couple of tests with the same batch of rocks.
After polish finishes
1. Rinse them really well. Do nothing else. Put them in the ultrasonic. 2. Rinse them really well. Wipe all of them thoroughly with a cloth. Put them in the ultrasonic. 3. Rinse them really well. Put them back in for a "burnish run" for a few hours. Rinse them really well. Put them in the ultrasonic.
Obviously not all in one go. Afterwards I'd put the same batch of rocks back into the polish stage for the usual length of time before each cleaning method. Then take pictures of the water and compare the cloudiness.
Here is a timelapse of me cleaning some quartz in the ultrasonic. It was pretty well fractured, so lots of cracks for polish to hide in. They were rinsed really well, but a burnish run was not done. To get accurate results I'd need to do the above tests with the exact same batch of rocks.
Post by hypodactylus on Apr 21, 2023 10:58:37 GMT -5
I was using a 'cheap' ultrasonic cleaner for a while. I stopped using it because it didn't seem to do a very good job. The water would get dirty (at least sometimes), but there still seemed to be grit/residue in the cracks and pits.
I found the hose nozzle on the 'shower' setting to generate enough pressure to do just as good or better in the cavities. Not to mention quicker and easier to use between stages. Not as doable in the winter though...
If that doesn't work, I'll use a toothbrush. If that doesn't work, well... I give up 🙂.
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amygdule: Divided by Bales of Alfalfa
Apr 27, 2024 20:02:37 GMT -5
Welcome to the Rock Tumbling Hobby Forum where we share a love of rocks and a sense of community as enduring as the stones we polish.
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