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Refining Fine Grog


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#1 Essaily

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Posted 10 December 2012 - 11:25 PM

I just bought a bag of Fine Grog. However on closer inspection its not so fine as I expected. Is there a dust safe way to make it finer? Would most people use a mortar and pestle?

#2 Round2potter

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Posted 11 December 2012 - 02:08 AM

Ball Mill??

But I would assume the grog would wear the balls and jar significantly.

Maybe you could find the perfect sized sieve and wet sieve out the finer stuff leaving the more rough stuff, but i would assume that the saze of the grog is mostly even so this would be a huge waste of time.
"There is no such thing as cheating in clay; So long as it works"

#3 Essaily

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Posted 11 December 2012 - 02:46 AM

Thanks, I may try a blender or make a ball mill.

#4 Marcia Selsor

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Posted 11 December 2012 - 08:23 AM

a rock tumbler works also.
old note from clay art.

If you wanted really fine grog for porcelain , you should get some mollochite.

Marcia

#5 TJR

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Posted 11 December 2012 - 10:06 AM

Grog comes in various sizes in the bag, from dust to larger. It is possible to sieve through a window screen, preferably wet, to avoid the dust. It you use your good glaze sieve, you will find that holes are filled with gravel. You could wet grind with a mortar and pestle. It is also possible to by a small ball mill for polishing quartz at a hobby store.
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#6 Ben

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Posted 11 December 2012 - 12:44 PM

I wouldn't think that you want to use either a ball mill or rock tumbler. I would think that most grog has irregular fractured surfaces. Wet grinding would round all those sharp edges and flat surfaces off. The clay won't stand up as well if you round off all the grog into ball bearing shapes.
As you state it your problem is one of size classification. What mesh size range is the grog supposed to be. "Fine" is only a relative term.

Grog can be supplied in a size range such as 40~60 mesh so that all the particles fit through a 40 mesh sieve but not through a 60 mesh sieve, or it can be supplied as a mesh size and smaller such as 40F (40 mesh with all finer particles included. everything passes through a 40 mesh sieve).

You could try sieving a small sample like 100 or 1000 grams to determine what size range you have. If you run it through a 40 mesh sieve and nothing gets stuck on the screen move up to 60 mesh etc.
Feel the results of each sieving and when you find one that is fine enough to suit you sieve the lot. Now you'll have a conundrum. What to do with the stuff that isn't fine enough?
How much are we talking about here? 5lbs or 50? For 5lbs I'd say mortar and pestle made from porcelain and fired high. For 50lbs... I have no idea. I guess sieve it and throw out the big stuff.

My 2 cents,
Ben

#7 perkolator

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Posted 11 December 2012 - 04:49 PM

you didn't mention what mesh size it is that you bought, or what size you need -- but why not just buy a finer mesh of grog? that will be the quickest and easiest way to get it. some grogs come pretty fine, like 200m - so it's definitely available.

just seems like a waste of time IMO trying to mill your own grog and minimize the dust hazard.

#8 Essaily

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Posted 11 December 2012 - 11:35 PM

Thanks for the great ideas! I shall try wet pounding and sieving. Thanks for the helpful advice all!




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