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Crank Clay Body Formula


Joe Mitchell

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Thanks...

Yes I understand that Crank Clay is a highly gorged sculpture body.

Most clay suppliers cary one or more sculpture bodies with grog.

I an sure any one would mix a body for me.

I am, as listed in my request, searching for a formula(s) for a crank clay body(s).

With a formula for crank clay, I would mix a sample and then could have it mixed in bulk

Thanks again...

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You could take just about any stoneware clay body recipe that's the color you want, and start increasing the grog until you get it where you want it. You may have to tweak the body flux a bit, but that wouldn't take much. There will be a lot of variability in how much grog you like, so with any clay body you're going to have to test a bunch. What cone, firing method and clay color are you looking for?

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I believe cranks are the older British term for saggars. Low coe, high thermal shock resistance clay, can be used at earthenware temps up to high fire. 

 

A quick troll on google came up with this recipe from Yakimono Toki, haven't a clue if it's any good but it seems logical for a saggar/crank body.

 

Petalite  40.5%  
Feldspar    4.5%  
Ball Clay  31.5%  
Stoneware Clay  13.5%  
XX Sagger or Fireclay  10%  
TOTAL  100 %  

 

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Thanks again........

I am not looking to create a stoneware body with some grog........

I want a FORMULA for crank clay.....

I am not looking for a body that is sorta like crank clay....

I want to mix, thus the formula, a crank clay body....

 

I'm trying to be helpful here, but you're going to have to give us some information since you're the one who knows what you're after. It's obvious that we don't have the actual formula for what the British supplier calls 'Crank Clay', because that is proprietary information. We're happy to help get you something close to that, but as of yet you haven't told us anything about the properties you're after. We can give you the information needed to start testing some clay bodies to get what you want, but we do not have the exact formula for that specific version of Crank Clay. So, again, what color, cone and firing technique will you be using? Do you need it to be vitrified?

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I apologize…to Alabama, Neil, Joel, and thank Min…

I did not understand that I was asking for a formula of a clay body called “crank†and may also be called “chamotte†that would be protected by a supplier of such a body.  I guess I thought it would be generic or common information. 

 

I have seen pictures of the clay body and have always wanted to see how it might feel and how it might react to hand building. I understand it is almost too rough to throw.

 

I work between cone 05 and cone 6.  Fire in an electric kiln. 

Create 12"x12", 12"x18" box forms that are mounted on a wall.

Suggestions of the amount of grog I might add to an existing body and maybe what the limits might be between clay body and grog.  

Alabama suggest 35%-50% .. will give that a try…

Also, suggestions on particle size might be helpful, also.

 

I will try the formula suggested also:

Petalite  40.5%  

Feldspar    4.5%  

Ball Clay  31.5%  

Stoneware Clay  13.5%  

XX Sagger or Fireclay  10%  

TOTAL  100 %  

 

Thanks again …..

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I would mix up some of the sculpture clays to start testing in this https://newpaltzceramics.files.wordpress.com/2013/09/virginia-scotchie-recipe-book.pdf instead of the recipe I posted yesterday. When you said crank clay I thought saggars therefore posted that one, but I think you could get one with better working properties than that one probably has with so much petalite in it.

 

Have you already tried commercially available sculpture or raku clays? Was there nothing suitable for what you are doing? 

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If you want something darker, add Redart or some other terra cotta clay to it.

 

If you're not worried about vitrification, you can get away with just about anything as far as the formula is concerned. I would start with something simple and cheap. According to the Bath Pottery Supply site, their crank clay is ball clay based, probably because ball clay is really cheap. So ball clay, a little fireclay, 2 or 3 sizes of grog, and enough feldspar to bind it together and you're good to go.

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