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docweathers

Testing 5 L Porcelain Bowl Mill Jars Yields Thin Skim Milk

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I got a couple of commercial 5 L porcelain ball mill jars and thought that I should test them before I committed my glazes to them, just to make sure that whatever casting residue that might come off initially would not contaminate my glazes.

 

I ran two different 5 L porcelain ball mill jars with 20 pounds alumina grinding balls and water for up to 13 hours. I change the water regularly, usually about every hour. Even after running this long, the water was still coming out a thin, opaque white liquid a little thinner than skim milk. This does not sound right to me since I thought the idea of a porcelain jar and alumina balls was to not leave any noticeable grinding residue in the glaze.

 

 What do you think? Has anyone tried this?

 

Thanks

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Larry;

I used to work at a pottery where we mixed our clay as a slip in a 30 gallon ball mill. Our glazes in a 10 gallon mill.Clays we ran for 4 hours then sieved through a 40 mesh. Because we ran the same claybody all the time, the washing was minimal. You would still have to wash the jars and take out the blass and wash them. We kept all the washing liquid, and recharged the mill with it and the porcelain balls.

Speed is critical with a ball mill. If too slow, you could be grinding the mill, if too fast, you could be pounding the insides. Take a look at Cardew's book; "Pioneer Pottery".

He talks about critical speeds.

The great thing about a ball mill for glazes, is that you are grinding at upwards of 200 mesh. You can then use local materials, such as wood ashes and coarse flint etc.If we ground quartz into silica, we calcined it first in a bisque, then ran the 10 gallon mill for 12 hours.

You have a great find. Just takes a bit of research. Have fun with it.

TJR.

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Larry if you can make skim milk in 13 hours you now will need a pasteurization plant and a bottling operation. This could really take off with zero cows and only a water supply needed-no messy cow poo and no feed supply. You could patent the whole process for big $$$.You will need some investors.

Mark

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mark, I like cow poo and find it is scarce in Deep South Texas compared to Angus heaven in Montana. Use is in pit firings and saggars.

As for Doc, keep rinsing out the water until it is clean. I don' t know what he jar was used for previously. Always rinsed the jar and balls as well as possible. what do you plan to use the milling for? I have a mill bu haven 't needed to use It in a year or so. are these commercially made milling stones?

 

Marcia

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Mark, I am looking to you as my primary fundraiser and investor for this project.    I'm sure the skim milk I am generating is a lot less fattening and lower cholesterol than anything currently on the market.

 

Jars and balls are new from one of the primary manufacturers in the US. I'm wondering if I'm the only guy who's ever tested these things with water before dumping some glaze in. Am I right in assuming these things are worthless if they are generating this white liquid after many long hours of grinding on water?

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Without a load of material in the mill with the grinding media, what you are "grinding" is the media and the mill lining itself. When there is a charge in the mill, the effects of the grinding are "spread out" on the material of the charge AND the media and the mill jar.

 

Ball mills will ALWAYS get a VERY small portion of the media content (porcelain) into the ground material. Nature of the beast. Slowly over time... the grinding media get smaller and smaller. This is normal.

 

It is usually such a small percentage of the total as to be insignificant.

 

If you keep doing that you are "eating up" your media and the jar.

 

best,

 

.................john

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Without a load of material in the mill with the grinding media, what you are "grinding" is the media and the mill lining itself. When there is a charge in the mill, the effects of the grinding are "spread out" on the material of the charge AND the media and the mill jar.

 

Ball mills will ALWAYS get a VERY small portion of the media content (porcelain) into the ground material. Nature of the beast. Slowly over time... the grinding media get smaller and smaller. This is normal.

 

It is usually such a small percentage of the total as to be insignificant.

 

If you keep doing that you are "eating up" your media and the jar.

 

best,

 

.................john

John;

Thanks for the very lucid explanation. That was what I was trying to say, but you said it better.

TJR.

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