Jump to content

Recommended Posts

 

I don't totally agree with the argument that no ball clay = no plasticity. Fireclays and stoneware clays certainly have plasticity. Maybe not the same as ball clay, but they're way more plastic than kaolin.

 

I'm with that thought also. 

 

The best clay body I've ever used is from Japan... and there is no ball clay in that.   Mostly (90+%) it is a naturally occurring stoneware clay from 1/4 of a mile from where we are making pots, plus a little fireclay addition from Shigaraki.  The processing is the key to the amazing plasticity and strength.  Dug with heavy equipment, left outside in a pile to "age" for a year, run thru three separate blunging operations (first one screening out the bigger stuff), filter pressed, batch mixed in a blade type mixer, then pugged.

 

Feels nothing like any clay body I've used in the USA.  When you first touch it for something like wedging... you say "UGH!"  Grainy, soft, mushy, come to mind.  You'd swear that you'd never be able to work with it.  Then you put it on a wheel............

 

best,

 

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

 

PS>  Fired to Orton cone 14.

 

Doesn't mean we couldn't find something like that here!  Sounds very interesting. Where exactly in Japan? The whole place is an island arc so its going to be some sort of volcanic derivative.  This sounds like fun except for the second part - finding out what the land regs are for any particular district here. You have to deal with that even at the small hobby level.

Share this post


Link to post
Share on other sites

Callie:

I have seen Terri use terms like magma, metamorphic, and call minerals by specific names: sorta knew she had a background.

 

So why is such a common term such as plasticity; so hard to wrap words around?

 

Nerd

Share this post


Link to post
Share on other sites

If it walks like a duck and quacks like a duck, it's a duck. Might be a mallard, or a wood duck or a pintail but it’s a duck. I don’t need to take it’s vital signs to know its a duck. Get your hands into the clay, make some pots and you know if it’s plastic. (think I might have to rent space in Bruce’s cave)

Share this post


Link to post
Share on other sites

If it walks like a duck and quacks like a duck, it's a duck. Might be a mallard, or a wood duck or a pintail but it’s a duck. I don’t need to take it’s vital signs to know its a duck. Get your hands into the clay, make some pots and you know if it’s plastic. (think I might have to rent space in Bruce’s cave)

 

As a bit of a "tech weenie" myself .................... I have studied these aspects of the craft heavily .... so that I can own them well enough to just let them go and work very intuitively. 

 

I got this core philosophy from the "folk potter"....HAMADA Shoji.  (Who had a formal post-secondary technical ceramics education before becoming a handcraft potter.)

 

best,

 

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

Min likes this

Share this post


Link to post
Share on other sites

I think lack of plasticity and shortness are two different things. Clay that is short has not been properly processed. If a clay body isn't run through a de-airing pugmill or isn't aged or isn't made from slip, it will be short. Too many tiny air pockets to create good bonds between the particles. Very plastic bodies can still be short. Shortness is a result of the mixing of the clay body. Plasticity in more about the nature of the materials themselves.

Share this post


Link to post
Share on other sites

Said by Nerd - "Why is the pottery industry not following the Atterberg limits more closely?"

 

Does anybody really believe that an "industry" that sells clay bodies as cone 6-10 would limit itself by technical standards?

 

dw

Share this post


Link to post
Share on other sites

Dick:

This is the reason my friends stopped coming by, I think about these things. Have been reading books on clay formulation from back in the 50's and 60's: most of today's, terms came from back then. Soil sciences has greatly advanced since then. Seen a few potters state that soil science does not apply to clay; forgetting clay is just processed dirt.

 

Matt.. That works, but I prefer high plasticity be called " play doughish.

 

Nerd

Share this post


Link to post
Share on other sites

Maybe the word we are looking for is "malleability" as defined in www.vocabulary.com: Malleability is the quality of something that can be shaped into something else without breaking, like the malleability of clay.

JK

Share this post


Link to post
Share on other sites

great suggestion, johnny.  perfect definition.

 

nerd, potters do not necessarily want to become scientists.  they just want to work and play with clay.  knowing exactly what is in it is not as important as what can be made with it.  it is wonderful that some people want to find out exactly ''what'' and ''why''  and "when" but i believe the average potter just wants to know "that".

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×