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Grinding Clay, Use A Hammer Mill?


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I am new to the forum, though not new to pottery. I make pit fired pottery reproductions of Anasazi pottery, as well as a kind of "fusion" that combines different pottery traditions.

 

I dig some of my clay, and I have typically ground it between two pieces of sandstone. This is tedious, tiring, and slow. I have wanted to grind it using a machine but here are my dilemmas. A corn grinder is barely an improvement over the native mano-metate approach and the hand-powered ones are hardly made to grind small pieces of sandstone. There are commercial grain grinders but again, they are

really engineered to grind wheat and corn. Bluebird (Colorado) used to manufacture a hammer mill for clay but no longer do so, and despite considerable effort, I have never been able to find a used one.

I've considered buying a grain grinder that works off a tractor PTO but mostly they're designed for large quantities, and I anticipate maybe grinding 200# a year. I have water processed clay before, but some clays have so much ionic attraction that they tend to clump up, making it impossible to strain them.

 

Anyone have any ideas of where to find a used hammer mill for grinding clay?

Kind thanks,

Wayne Keene

Cortez, CO

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@waykee7@q.com Wayne,
Welcome to the forum! When you have a few minutes, please add some information to your profile...this is a friendly group and it is nice to know who you are talking/writing to.

I was with you on this until you reached the 200 lbs of clay per year.  I process a couple hundred pounds of dried clay each week and  use a piece of 4x4 in a study wooden box (think milk churn) to pound clay into relatively course powder.  I create enough dust doin it this way that I wear a heavily filtered, respirator mask.  I can only image the amount of dust that a mechanical grinder would produce.  Have you considered a ball mill?  At least that would be enclosed...and with stainless steel balls would certainly pulverize the clay to a fine powder.

Keep us posted on what you decide to do,

-Paul

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200#   why buy anything

 

use the human hammer mill

a sledge hammer, and a 5 gal bucket.

never more than 10 pounds in bucket

think butter churn

ive made dust out granite chips and feldspar chips  should be fine with clay

 

another suggestion was to place  clay,  stones etc between 2 metal plates drive car over.... refill and repeat

 

a ball mill would also work

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I missed this topic when it first came out. These guys are right. For the small amt. of clay you are processing, break up the pieces on a piece of canvas with a ballpene hammer.

If you are serious about crushing stuff, check out geology depts. of govt. surplus.

This is the order you crush;

1,Hammer mill or jaw crusher.

2. Plate mill or corn grinder.

3.Ball mill.

If you calcine flint or granite at bisque temps in your kiln, you can grind them too.

TJR.

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  • 3 weeks later...

 

 

I couldn't find it in archives but Tyler Miller covered this in a post where he explained his method.

His method gives the potter the option of handbuilding or throwing with the natural clays.

 

A hammer mill puts this on a difficult level than it needs to be.  Its called primitive pottery because

it is a back to basics method that is simply easy and fast. 

 

The hammer mill is used best for breaking glass down for glazes.  

 

See ya,

Alabama

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Is using a twenty dollar walmart blender out of the question? Ive done this time and time again. Ive screened local raw clay wet, dried, broken, and then add the chunks (1 to 1.5 inch in size) and blend. Ill take the blender and shake it as it blends to get it going. Blends to a find powder with no problem. I sift off the little bits and repeat. Works good, fast, and surprisingly enough the blender has yet to die.

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I vote for the wet method and here's why, time.

get your 5 gal bucket and add 5~10 lbs of clay and will with water (5 minutes) then GO AWAY for a day

get your drill mounted paint mixer and stir the hell out of it (5 minutes) then GO AWAY for a couple of hours

carefully pour off the top layers into another bucket, straining through window screen if you want (5 minutes)You can add water back to the first bucket if you want and repeat the next steps, then GO AWAY for a day

pour the water off the second bucket then pour the slip into a goodwill pillow case (5 minutes) then go away til its ready

 

20 minutes work time for usable clay that is properly hydrated.

 

Keeps dust down too though I do this outside for that reason.

 

 

This is an excluding process. If there are things in the clay that you don't want and they are large particle or will settle this method will exclude them.

Some particles may be excluded that you don't want excluded fyi (mica etc) so be aware of that.

 

I have a local earthenware that is full of limestone and pops out pretty badly unless I use this method to get the limestone sand out.

 

have fun!

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