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#1 Biglou13

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Posted 06 May 2013 - 10:16 PM

Ok I want to make my own clay.

Everyone says cheaper to buy. But I still wanna do it. (Hardheaded, mom said so)

I'm over digging locally. Romantic but sounds like to much work.....

epk is mined near where I live, And Lizella is a day drive.

I'd like to make a clay with these 2 as major components. Lizella and EPK. (If not. Edgar lives closer)

The usual suspects (supplies/raw materials) should be available from local supplier.

What I know about making clay I learned from the internets (and i stayed at holiday inn), and from some geat articles here at the CAD."raw materials"

Perhaps one / some of the Jedi masters will enlighten. This (not so) young padwan learner, with a little how to/ 101.

I currently only have access to cone 6 electric, so it would,have to work starting in that range.

I like groggy bodies so that would be good. But that is a easlily added option

It would be great if clay could also fire higher, and perform and look great in wood fire. (Hey a young padwan can dream)

I'm also a fan of darkish clays.... Shouldnt be problem with lizella, but I do dislike boring terracotta color (not to discriminate against the blancos) and color is secondary to performance.

Please advise.......

Again any help is always appreciated. ( so is the ocassional ribbing)
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#2 AtomicAxe

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Posted 06 May 2013 - 11:16 PM

A lot of designing a clay body is making clay that matures and doesn't slump at the cone you want to use.

http://www.ceramicin...kage-absorption
http://digitalfire.c...bodies_211.html
http://digitalfire.c...t_bars_214.html

Those pages have info on testing the clays, what you want to do is limit shrinkage, while still providing a 'plastic' clay body that has strength and doesn't absorb liquids when high fired.

Ideal for you would be to try to design a versatile clay body that can get to cone 10 reduction no problem but functional at cone 6. also having your basic 4 ingredients in bag or half bag amounts in a batch would make it easier to make and produce without the pain of having bins to measure out single pound increments. sooooo ...

I would probably start with ...

lizella 25
epk 12.5
fire clay 25
neph sy 12.5
fine grog 12.5
flint 12.5

I would also try

lizella 37.5
feldspar 25
fireclay 12.5
epk 12.5
flint 12.5
fine grog ... maybe 5

From there you could probably hit it spot on ... but really it depends on your testing you do post ... so prepare for line blends to achieve what you want.

and ask offcenter also ... it's his part of the woods.

OH ... and if either of those pan out as is ... those clay bodies will be named "Funk Nasty Red: The Movie"

#3 TJR

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Posted 07 May 2013 - 08:31 AM

If I knew what Lizella clay was, I could put my oar in, so to speak. If you are near an EPK deposit, you are laughing. You would need a ball clay as well for plasticity. Since EPK is a refractory clay you could even consider making refractories like kiln posts out of it.Is Lizella a ball clay?
Try a 50/50 mix, 70/30 [Epk,Lizella [, and 30/70[RPK and Lizella.
Make some shrinkage bars to see how it holds up, and make some vertical test tiles to see if it slumps.
TJR.



#4 OffCenter

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Posted 07 May 2013 - 09:08 AM

If I knew what Lizella clay was, I could put my oar in, so to speak. If you are near an EPK deposit, you are laughing. You would need a ball clay as well for plasticity. Since EPK is a refractory clay you could even consider making refractories like kiln posts out of it.Is Lizella a ball clay?
Try a 50/50 mix, 70/30 [Epk,Lizella [, and 30/70[RPK and Lizella.
Make some shrinkage bars to sea how it holds up, and make some vertical test tiles to see if it slumps.
TJR.


No, Lizella isn't a ball clay. It is often called an earthenware or even terra cotta because of its color and original use for flower pots fired to about cone 010, but it is really a cone 8 stoneware. Best color around cone 5. Will go up to cone 10 but will start to deform if held at 10 for long. Beautiful clay but even at cone 8 or above will leak unless neph sy is added to it.

Jim
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#5 Min

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Posted 07 May 2013 - 03:33 PM

From Val Cushing's Handbook:

Fires orange brown "easy" platic body

Goldart 30

Hawthorne 30

Lizella 40

Another one, dark brown to black, this one is oxidation only as it will melt or become brittle in reduction due to high iron content:

C&C Ball Clay 10

Goldart 15

Hawthorne 15

Blackbird 10

Lizella 50

One more, cinnamon throwing body:

OM4 20

Goldart 35

Hawthorne 15

Lizella 20

Soda spar 10

And if you want a tan colour and a sandy body:

OM4 25

Goldart 25

Hawthorne 25

Lizella 10

Talc 5

Nepsy 10

I have made up a couple of his white bodies, the translucent porcelain is terrific, haven't used any of the above recipes. Maybe a blend of the second body with one of the others?

Min

#6 futurebird

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Posted 07 May 2013 - 03:45 PM

Is there a good book that I could read that would teach me about this topic?
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#7 AtomicAxe

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Posted 08 May 2013 - 12:30 PM

Figured I should also give you my old ocmulgee ^10 body ... if you can find a substitute for AP Green (no longer available) ... from what Offcenter has said, lizella is just a hop skip and jump from ocmulgee so the clay should be similar if not exact.

AP green - 33
OM4 - 33
Ocmulgee - 17
Grog - 10
Spodumene - 7

Just a brief search on digital fire suggests that Plainsman fireclay is a substitute but I've never seen it before.

#8 oldlady

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Posted 08 May 2013 - 02:27 PM

smooth redbrown clay without grog fires at cone 6

100 lb redart
100 lb XX sagger
plus
water
makes more than 200 lb great clay for under $25.

from Robin Teas who found that her students did not want to 'waste' their expensive purchased clay to practice throwing. '


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#9 AtomicAxe

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Posted 08 May 2013 - 04:18 PM

I hate 2 ingredient clay bodies. And redart is nothing like lizella/ocmulgee.


That being said, here is a few from val cushing back in the day that use ocmulgee and in his ^4-^6 clay bodies ... you can probably substitute pine lake fireclay with hawthorn or just about any fire clay ... but easy enough to do.

http://www.studiopot...les/art0009.htm

#10 oldlady

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Posted 09 May 2013 - 10:53 PM

hey, axe, you don't like 2 ingredient clay but you are not the person who asked. the heading is making clay 101, i think that is for a basic clay that will work at cone 6. i didn't see anything in the original question that prevents the use of purchased dry ingredients. nothing says lizella and epk are required in the recipe.

this dark red clay works well at cone 6, is easy to throw and i used it for several years with much success. it is a good, basic clay. add grog if you like. that will make it a 3 ingredient clay. much better.

go easy on those of us without your technical skills.
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#11 AtomicAxe

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Posted 10 May 2013 - 01:53 AM

hey, axe, you don't like 2 ingredient clay but you are not the person who asked. the heading is making clay 101, i think that is for a basic clay that will work at cone 6. i didn't see anything in the original question that prevents the use of purchased dry ingredients. nothing says lizella and epk are required in the recipe.

this dark red clay works well at cone 6, is easy to throw and i used it for several years with much success. it is a good, basic clay. add grog if you like. that will make it a 3 ingredient clay. much better.

go easy on those of us without your technical skills.


1. Chill out.
2. What I expressed was personal preference, nothing technical.
3. I still hate 2 ingredient clay bodies.

4. ...

I'd like to make a clay with these 2 as major components. Lizella and EPK. (If not. Edgar lives closer)


Boosh.

#12 JBaymore

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Posted 18 May 2013 - 10:08 PM

Be careful taking bodies with little devloped glassy phase (becasue of no spar, frit, or neph. sy. content .... yeah...spodumene counts here.....) up to higher temperatures above the 1100 C / 2012 F range........ particularily with longer firing cycles. They are prone to having the non-melted silica on the body converted to the cristabolite form of SiO2 ..... which has a nasty huge impact on the COE of the body. Can cause dunting issues on kiln cooling...and also cracking in the domestic oven temperature range. The amount of cristobolite developed is linerally related to the time spent above 1100 / 2012.. ..... twice asl long... twice the conversion level.

Some of these above recipes would tend to have that issue, I think. Cone 6 is typically reached above that temperature for most typical rates of climb.

best,

.......................john
John Baymore
Immediate Past President; Potters Council
Professor of Ceramics; New Hampshire Insitute of Art

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#13 oldlady

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Posted 19 May 2013 - 10:15 AM

John baymore,

could you be more specific about which formula you are referring to in the above comment?
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#14 JBaymore

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Posted 19 May 2013 - 11:03 AM

Body formulations with nothing supplying additional sources of fluxing materials to cause more of the SiO2 in the clay components (both as trace admixtures and from the kaolin/metakolin silica ejection) to convert to a glassy phase. Depending on the firing range, if you don't see an addition of feldspar, neph. sy., frit, sometimes spodumene, or the like in the formulation..... there there is the possibility of the issues I mentioned.

best,


....................john
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Immediate Past President; Potters Council
Professor of Ceramics; New Hampshire Insitute of Art

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#15 Min

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Posted 19 May 2013 - 11:38 AM

Be careful taking bodies with little devloped glassy phase (becasue of no spar, frit, or neph. sy. content .... yeah...spodumene counts here.....) up to higher temperatures above the 1100 C / 2012 F range........ particularily with longer firing cycles. They are prone to having the non-melted silica on the body converted to the cristabolite form of SiO2 ..... which has a nasty huge impact on the COE of the body. Can cause dunting issues on kiln cooling...and also cracking in the domestic oven temperature range. The amount of cristobolite developed is linerally related to the time spent above 1100 / 2012.. ..... twice asl long... twice the conversion level.

Some of these above recipes would tend to have that issue, I think. Cone 6 is typically reached above that temperature for most typical rates of climb.

best,

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


John, would you consider the iron content in some of the above clays an adequate flux if firing reduction?


Min

#16 oldlady

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Posted 19 May 2013 - 01:09 PM

OK

now i feel like a 2nd grader in a calculus class. i will go to my corner and sit.
"putting you down does not raise me up."

#17 Biglou13

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Posted 19 May 2013 - 02:42 PM

OK

now i feel like a 2nd grader in a calculus class. i will go to my corner and sit.


It usually takes me a few days and hours on the Internet before it sinks in and I start to understand.
Caution big brother is watching.
The beige is blinding!!!!!!
The middle of the road is boring

The true sign of intelligence is not knowledge but imagination.
-Albert Einstein

#18 JBaymore

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Posted 19 May 2013 - 06:44 PM

John, would you consider the iron content in some of the above clays an adequate flux if firing reduction?


The iron in the reduced FeO state is an active flux on silica (SiO2), for sure, and it begins its action at quite low temperatures. So yes, it will add some fluxing of the available silica and keep that silica from potentialy converting to the chrstobolite phase form. Unfortunately, iron fluxed silica glass is very brittle... so the body's glassy phase in that case is not a very optimal one to use to "glue things together".

Plus the iron/silica melt has a low melting temperature and also a low volitilization temperature... possibly accounting for some additional bloating issues.

A particulary bad combo is a somewhat high iron body with inadequate sourcing of other fluxes. You end up with a brittle body that is getting "loaded" upon uneven cooling (or reheating in food service) by excessive COE factor from the cristobolite... and BANG..... dunting.

best,

.......................john
John Baymore
Immediate Past President; Potters Council
Professor of Ceramics; New Hampshire Insitute of Art

http://www.JohnBaymore.com

#19 JBaymore

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Posted 19 May 2013 - 06:46 PM

OK

now i feel like a 2nd grader in a calculus class. i will go to my corner and sit.



Body formulations with nothing supplying additional sources of fluxing materials to cause more of the SiO2 in the clay components (both as trace admixtures and from the kaolin/metakolin silica ejection) to convert to a glassy phase. Depending on the firing range, if you don't see an addition of feldspar, neph. sy., frit, sometimes spodumene, or the like in the formulation..... there there is the possibility of the issues I mentioned.


That (in red) is the key phrase in there..... any of the recipes that don't have those materials listed are the ones I am talking about.

Does that help?

best,

...................john
John Baymore
Immediate Past President; Potters Council
Professor of Ceramics; New Hampshire Insitute of Art

http://www.JohnBaymore.com

#20 Biglou13

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Posted 06 June 2013 - 10:19 PM

A lot of designing a clay body is making clay that matures and doesn't slump at the cone you want to use.

http://www.ceramicin...kage-absorption
http://digitalfire.c...bodies_211.html
http://digitalfire.c...t_bars_214.html

Those pages have info on testing the clays, what you want to do is limit shrinkage, while still providing a 'plastic' clay body that has strength and doesn't absorb liquids when high fired.

Ideal for you would be to try to design a versatile clay body that can get to cone 10 reduction no problem but functional at cone 6. also having your basic 4 ingredients in bag or half bag amounts in a batch would make it easier to make and produce without the pain of having bins to measure out single pound increments. sooooo ...

I would probably start with ...

lizella 25
epk 12.5
fire clay 25
neph sy 12.5
fine grog 12.5
flint 12.5

I would also try

lizella 37.5
feldspar 25
fireclay 12.5
epk 12.5
flint 12.5
fine grog ... maybe 5

From there you could probably hit it spot on ... but really it depends on your testing you do post ... so prepare for line blends to achieve what you want.

and ask offcenter also ... it's his part of the woods.

OH ... and if either of those pan out as is ... those clay bodies will be named "Funk Nasty Red: The Movie"


Found some fire clay. At local hardware/ag store.

Is this any different than fire clay fom pottery supply?
Caution big brother is watching.
The beige is blinding!!!!!!
The middle of the road is boring

The true sign of intelligence is not knowledge but imagination.
-Albert Einstein




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