navi
starting to spend too much on rocks
Member since November 2008
Posts: 229
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Post by navi on Jan 12, 2009 9:58:17 GMT -5
i'm doing a coarse grind of agates. last week, i did a different batch in a coarse grind, also of agates. 3/4 full of stones and water to the bottom of the top layer of stones.
at least that's how it was when i started the loads!!!
today is day 5, and i noticed that my water level is around 8/10ths full!!! same thing happened last batch. this batch, the level started at around 2/3rds. what the heck is going on? it's not like there is a bunch of heat in there expanding everything.
i am confused.
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drjo
fully equipped rock polisher
Honduran Opal & DIY Nut
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Post by drjo on Jan 12, 2009 10:29:42 GMT -5
Do you mean compared to the bottom of the top layer of rocks?
First thing that comes to mind is the rocks are getting smaller and creating sludge that displaces the water.
Or you've got a REALLY bad humidity problem ;D.
Dr Joe
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Post by Bikerrandy on Jan 12, 2009 10:34:20 GMT -5
That's the tumbler, it's sucking the life out of the rocks. ;D
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Saskrock
fully equipped rock polisher
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Post by Saskrock on Jan 12, 2009 13:11:03 GMT -5
My rocks always get smaller  !!! Whats your secret?   |
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navi
starting to spend too much on rocks
Member since November 2008
Posts: 229
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Post by navi on Jan 12, 2009 21:31:42 GMT -5
let me clarify. there is more water in there now, than when i started.
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Sabre52
Cave Dweller 
Me and my gal, Rosie
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Post by Sabre52 on Jan 12, 2009 21:37:35 GMT -5
*L* To quote the bad guy from Princess Bride " Why why, that's thimply inconthievable!". I would venture to say the water level may seem different compared to when the rocks were unground and no displacement had taken place but the amount of water remains the same....Mel
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navi
starting to spend too much on rocks
Member since November 2008
Posts: 229
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Post by navi on Jan 12, 2009 22:54:31 GMT -5
really, i'm not making this up and it's not some sort of illusion. in fact, i thought i started with TOO LITTLE WATER and now, the water level is about a half/three-quarters of an inch from the lid!!!!
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Post by snowdog on Jan 12, 2009 23:24:41 GMT -5
prob the amount of grinding it has done now allows all the rocks to sit closer to each other and not have as much space for the water to fill so it looks like it is higher
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Saskrock
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Post by Saskrock on Jan 12, 2009 23:45:18 GMT -5
Well it can't be the rocks getting bigger. Rocks sitting closer would still be the same amount of rock (if you include the ground off bits which are stil in there). The only thing that could be happening is some sort of aeration of the water causing it to foam up, kind of like making whip cream. Now how that could be happening with agates,grit and water? ?? Do you put in anything to thicken the slurry? Does it happen with anything other than agates? Is the water in Fenton drinkable? ;D |
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ejs
spending too much on rocks
Member since July 2008
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Post by ejs on Jan 13, 2009 10:04:31 GMT -5
Since I know of no mechanism that would allow for the creation of water within your barrel, I suggest that you start over, measure the amount of water going in, weigh the rocks and the grit, and then do the same at the end. I think you'll find that no physical laws have been broken. :-)
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huffstuff
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Post by huffstuff on Jan 13, 2009 17:54:20 GMT -5
I'm with saskrock, sometimes my sludge starts to look and feel more like chocolate mousse! Sometimes it foams, sometimes it doesn't.
I think what we're all trying to say is, don't worry!
Amy
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fanatic
starting to spend too much on rocks
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Post by fanatic on Jan 13, 2009 19:28:31 GMT -5
I agree with Amy. Listen to the tumbler and it will tell you if your load is right. Ignore the looks of the slurry and look at the condition of the rocks. I went through this too....think everyone does at one time or another. Now I NEVER open a tumbler until it reaches its target time, sounds way too loud, or isn't making any sound at all. patience!!
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Rogue Trader
freely admits to licking rocks
"Don't cry because you are leaving, smile because you were there."
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Post by Rogue Trader on Jan 13, 2009 20:47:51 GMT -5
It's called displacement.
As the rocks grind down the initial rough edges they fit together better. Therefore the rocks sink under the level of the water and push it up. As the level of grind proceeds the rocks will get smaller and the water level will reduce slightly.
In fluid mechanics, displacement occurs when an object is immersed in a fluid, pushing it out of the way and taking its place. The volume of the fluid displaced can then be measured, and from this the volume of the immersed object can be deduced (the volume of the immersed object will be exactly equal to the volume of the displaced fluid).
An object that sinks displaces an amount of fluid equal to the object's volume. Thus buoyancy is expressed through Archimedes' Principle, which states that the weight of the object is reduced by its volume multiplied by the density of the fluid. If the weight of the object is less than this displaced quantity, the object floats; if more, it sinks. The amount of fluid displaced is directly related (via Archimedes' Principle) to its weight.
In the case of an object that sinks (is totally submerged), the volume of the object is displaced. In the case of an object that floats, the amount of fluid displaced will be equal in weight to the displacing object.
Because rocks are crystaline, and therefore will contain miniscule pockets of air, as the rocks grind down further the air is released and the water displacement reduces because the total mass (NOT weight) of the rock is reduced.
Furthermore, the actual grinding of the rock and the creation of slurry will not create or reduce water content within the air tight / water tight barrel. Slurry consists of extra extra fine particles of the rock/grit in suspension in the water.
If you were to do your tumbling in a clear scratch proof container and place 6 oz of rocks, and 3 oz of grit in the container and filled with 6 oz of water (total weight 15 oz) you would be able to see the level of the water. As the rocks grind down (as previously explained) they sink below the level of the water and therefore displace more. However, displacement only works to a finite level. In this case it would be 9 oz displacement (rock/grit).
Using your clear barrel as a looking glass. When you stop the tumbling motion, stand the barrel on end and watch the slurry begin to settle you will note that the water level stays at the same final level. All that happens is that the miniscule particles of rock fall to the floor of the container and press down (gravity), therefore removing any water and/or air between the particles.
Should you be able to create a complete vacuum within the clear barrel you will notice that the liquid (water) will not clear and the particles of rock will remain in suspension. Complete vacumm removes all gravitational pull/push forces.
So, with our initial load of 6 oz of water, 6 oz of rock and 3 oz of grit, once complete grind has occured (to which ever level of micron size you wish to grind to) you would still have the same weight/volume of each item (rock waste matter, grit waste matter and water).
Further more, due to residule evaporation, and the hydroscopic properties of the rock/grit combination you will still have a full mass of 15 oz minus atmospheric evaporation of water. Should you then be able to completely seperate the chemical composition of the rock/grit/water you will find that you will still have the same weigh/volume of rock/grit/water. ;D
Here endeth the lesson ;D
Tomorrow we will study Newtons Laws of Motion ;D ;D ;D
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Post by NatureNut on Jan 13, 2009 21:37:54 GMT -5
I agree with Rogue (although all other hypotheses are highly probable). Rocks now smaller and rounder settling to bottom and filling the bottom forcing water to top, causing water level to rise. Either that or your rocks were filled with water and the water came out! LOL. (not a serious guess) Jo
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Post by frane on Jan 13, 2009 22:13:44 GMT -5
Yep, don't worry about it. Also, sometimes agates have little pockets that hold air. You ware it down and it looks like you have more water covering them as they ware. Too much water, drain a little and keep tumbling. Completely normal so don't worry.
Fran
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Deleted
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Post by Deleted on Jan 13, 2009 22:26:45 GMT -5
Rogue: Say what? LOL. Just kidding. Thanks for the lesson, I did read it and look forward to tomorrows lesson.  Shannon |
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navi
starting to spend too much on rocks
Member since November 2008
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Post by navi on Jan 13, 2009 23:13:06 GMT -5
rogue, that actually made sense!!! gotta be the reason. blame it on physics!!!!
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Saskrock
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Post by Saskrock on Jan 14, 2009 0:31:50 GMT -5
Hold on what rogue says makes sense, but only if he tumbles in way less water than I do. When I do a batch I put in rock to 3/4 full, add grit, add enough water to cover the rocks completely. The rocks are already submerged so they will never displace more water no mater how they fit together. Is everyone else using way less water than me? ?? Maybe I can get a better shine with less water? What is everyone else doing? This is going to drive me crazy.  have to say though this part, Should you be able to create a complete vacuum within the clear barrel you will notice that the liquid (water) will not clear and the particles of rock will remain in suspension. Complete vacuum removes all gravitational pull/push forces. Not a chance, creating a vacuum would first of all be impossible because lowering the pressure would cause the water to boil. You wouldn't get a vacuum until the water was boiled off gone. Even if we pretend that the water would not boil it would have no effect on gravity. Gravity is a result of mass and decreases exponentially with distance. If vacuum had this effect it would have been impossible to walk on the moon in the vacuum of space. A gravitational push has never been shown to exist either. Everthing else works if less water is used though. So now I gotta know. How much water does everyone else use. |
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Post by Lady B on Jan 14, 2009 1:00:02 GMT -5
This has been a great thread to read and enjoy. I love when things don't seem quite what they are.
Rogue has explained the situation beautifully and very thoroughly.
Another perspective - and not nearly so thorough as Rogue - is to consider the density of the fresh versus the tumbled barrel.
When we first start the tumble, in go the stones, the grit, and the water. This is a spacious liquid submersion. Lots of room (at least for the grit and the water) to move about. But as the grit works its magic, and a slurry forms, the liquid is no longer spacious. It thickens and there is less room for suspension within the entire load. The water probably still weighs less than the stones or the grit, though, so it will lie closer to the top of the barrel than the other ingredients. Because the density is changing, the mass is also changing which can cause a shift in relative positions of each component. But the weight of the barrel's contents, overall, will remain the same.
Think of ice cubes in a glass. Add water to just under the top of the highest cubes. While the ice cubes are intact, the liquid appears to be lower in the glass but as the icecubes are worn down, the liquid appears to rise. The weight remains the same but the density of the chilled beverage and the mass change as the components within the glass take on new characterisitics.
The bottom line...sounds like this Tumbler is doing just the right thing when it comes to tumbling! And look at how much thinking this little query got all of us to do! FANTASTIC!!!
Now, be sure to let us see the end results of your tumbles, Navi! ;D
Lady B
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Rogue Trader
freely admits to licking rocks
"Don't cry because you are leaving, smile because you were there."
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Post by Rogue Trader on Jan 14, 2009 4:06:28 GMT -5
If vacuum had this effect it would have been impossible to walk on the moon in the vacuum of space. A gravitational push has never been shown to exist either. A gravitational push has never been shown to exist, that means in theory Newtons Third Law of Motion is flawed: For every action there is an equal and opposite reaction! However, on this point I will concede that perhaps my wording was slightly imbalanced and it would have been more appropriate for me to have written atmospheric push/gravitational pull. I concur that a total vacuum has never been produced. Removing air/atoms from a vessel to create a vacuum also de-stabilises the atoms used in the manufacture of the vessel be they natural substances or man made. As to walking on the moon, inner space is not a complete vacuum. The atmospheric pressure on the moon is only 17% of that of earth, therefore not a complete vacuum, but devoid of air molecules/particles/atoms/matter that aid and sustain human/animal life (as we know it). |
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!!! Whats your secret?
