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My Head's Full Of Clay, But Which One?


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#1 TBm

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Posted 03 June 2010 - 12:16 PM

I'm in my Confused Early Stages, so please bear with me.

MY QUESTION
Should I choose a STONEWARE clay body such as Minnesota Clay MB STONEWARE
or a lower-fire EARTHENWARE?


BASIS FOR QUESTION:

LACK OF EXPERIENCE
I'm new to this and want to keep things as simple as possible.

INTENDED WORK PRODUCT
Tiles and larger flat forms involving relief sculpture - to be affixed to interiors of buildings as typical cermamic tile is. A kitchen backsplash, a fireplace surround, a segmented mural.

PAPER CLAY
I intend to use paper clay methods as much as possible.

KILN CONSTRUCTION and ENERGY COST ECONOMY
I hope to build a natural gas kiln. I want to limit energy costs and kiln construction costs as much as possible. Am I correct in thinking earthenware clays and related glazes fire at much lower temperatures than do stoneware clays. Will choosing an earthenware instead significantly reduce my firing costs and kiln construction costs? Any advice appreciated.

STANDARD of ABUSE
Finished product must withstand the knocks and scapes and washings that occur in any household. Imagine the abuse a doorframe suffers. In many instances, I will not employ a glaze. My work does not need to hold water (as vitirified clay can) but it will likely be washed with water and mild cleaning products occasionally - especially if a kitchen surface. Would an earthenware body stand up to houshold impact and washings, or must I opt for stoneware fired to vitrification?

WHITE
I want as white a clay body as possible. The MB Stoneware (per link above) fires nearly white in oxidation. Is there an earthenware that will meet the "abuse standard" described above and also fire nearly white in oxidation?


If my question is too broad, can someone please point me in the direction of an online source whereby I can educate myself further.

Thanks,
Tom

#2 TBm

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Posted 03 June 2010 - 10:47 PM

Nobody?



#3 Chris Clyburn

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Posted 03 June 2010 - 11:15 PM

I'm in my Confused Early Stages, so please bear with me.

MY QUESTION
Should I choose a STONEWARE clay body such as Minnesota Clay MB STONEWARE
or a lower-fire EARTHENWARE?


BASIS FOR QUESTION:

LACK OF EXPERIENCE
I'm new to this and want to keep things as simple as possible.

INTENDED WORK PRODUCT
Tiles and larger flat forms involving relief sculpture to be affixed to interiors of buildings - as in the case of a kitchen backsplash, a fireplace surround, a segmented mural.

TECHNIQUES
Handbuild, carve, press mold and slip mold.

PAPER CLAY
I intend to use paper clay methods as much as possible.

KILN CONSTRUCTION and ENERGY COST ECONOMY
I hope to build a natural gas kiln. I want to limit energy costs and kiln construction costs as much as possible. Am I correct in thinking earthenware clays and related glazes fire at much lower temperatures than do stoneware clays. If so, perhaps I do not need a stoneware clay body... Perhaps choosing an earthenware instead will significantly reduce my firing costs and kiln construction costs(?). Any advice appreciated.

STANDARD of ABUSE
Finished product must withstand the knocks and scapes and washings that occur in any household. Imagine the abuse a doorframe suffers. In many instances, I will not employ a glaze. My work does not need to hold water (as vitirified clay can) but it will likely be washed with water and mild cleaning products occassionally - especially if a kitchen surface. Would an earthenware body stand up to houshold impact and washings, or must I opt for vitrified stoneware?

WHITE
I want as white a claybody as possible. The MB Stoneware (per link above) fires nearly white in oxidation. Is there an earthenware that will meet the "abuse standard" described above and also fire nearly white in oxidation?


If my question is too broad, can someone please point me in the direction of an online source whereby I can educate myself further.

Thanks,
Tom




I think you'd be better off with a more vitrified clay. The less vitrified a clay is, the more fragile it is in my experience. Stoneware would hold up much better especially unglazed, than earthenware under those conditions. Earthenware generally fires at cone 04-01 (roughly 1945 F to 2046 F at a firing rate of 108 F per hour during the final ramp) whereas a typical stoneware body fires at between cone 3 to cone 10 (roughly 2106 F to 2345 F at a firing rate of 108 F per hour during the final ramp) depending on the body, with cone 6 (roughly 2232 F at a firing rate of 108F per hour during the final ramp) being very popular right now.

The clay body you listed is rated cone 6-10 which means it would not be truly vitrified until cone 10, and would not be as durable at cone 6 or as white, but it would still be stronger than earthenware. If you found a white stoneware that matured at cone 6 or lower without such a broad firing range, you would be better off something like Highwater's Little Loafer's which is cone5-6 or another similar body (it's late and that's the only white stoneware with a narrow range I could find quickly ..sorry) You might also look at Lagina's paper clays, a cone 6 porcelain or a cone 6 white sculpture clay.

The cost difference between earthenware and stoneware when once fired is very little, if you bisque first it become more noticeable but not enough to offset the difference in durability in my opinion



#4 Chris Clyburn

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Posted 03 June 2010 - 11:16 PM

Nobody?



You have to be a little patient :-) Clay forums tend to move slowly, kinda like the clay process itself




#5 Chris Clyburn

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Posted 03 June 2010 - 11:20 PM

Just an addendum, I mentioned a cone 6 porcelain as an alternative, but I neglected to state that porcelain is more finicky for hand-building, and significantly more expensive (between $.60 to $.80 per pound as opposed to $.19 to $.40 per pound for stoneware)

#6 TBm

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Posted 04 June 2010 - 09:21 AM

Apologies for my impatience. It's really just enthusiasm plus a strong desire to get started. Point taken.


I think you'd be better off with a more vitrified clay. The less vitrified a clay is, the more fragile it is in my experience. Stoneware would hold up much better especially unglazed, than earthenware under those conditions.

Thanks for your helpful insights, Chris. I'm very process-oriented but ignorant regarding these technical issues. Can you (or anyone here) suggest an online primer or book I can consult in order to bring myself up to speed? Thanks for confirming the superior strength of vitrified stoneware vs. earthenware, especially when unglazed.



...typical stoneware body fires at between cone 3 to cone 10 (roughly 2106 F to 2345 F at a firing rate of 108 F per hour during the final ramp) depending on the body, with cone 6 (roughly 2232 F at a firing rate of 108F per hour during the final ramp) being very popular right now.

It sounds like stoneware at cone 6 might be optimal for me: suitable strength and durability at minimal temperature, with minimal fuel costs and (maybe) reduced kiln construction costs. I understand the gist, but would appreciate a clarification:

Q1. What does this mean, "...at a firing rate of 108F per hour during the final ramp"?

I think it describes a carefully monitored temperature change, but I don't understand the specifics. Clearly I need to study up, but appreciate any elaboration in the meantime.



The clay body you listed is rated cone 6-10 which means it would not be truly vitrified until cone 10, and would not be as durable at cone 6 or as white.
If you found a white stoneware that matured at cone 6 or lower without such a broad firing range, you would be better off
- something like Highwater's Little Loafer's which is cone5-6 or another similar body
- You might also look at Lagina's paper clays, a cone 6 porcelain or a cone 6 white sculpture clay.

Again I did not understand the significance of these issues. I thought a broad firing range was a 'pure benefit' because I didn't realize strength and color would vary based on firing temps within that range.... Duh.

Q2. So is this right? I need a STONEWARE CLAY BODY with a narrow firing range, that vitrifies nearly white at cone 6 or lower.

If I cannot find something that fires nearly WHITE, I could substitute two options instead: a gray (cool) and a buff/tan (warm).



The cost difference between earthenware and stoneware when once fired is very little, if you bisque first it become more noticeable but not enough to offset the difference in durability in my opinion.

This kind of advice from someone who knows is most helpful. I'm "100% theoretical" at this point and I understand what a handicap that is.

Q3. I've read that in some cases bone dry paper clay can be glazed and fired in a single firing. Is that accurate? Are there special considerations or conditions?

Q4. "The cost difference between earthenware and stoneware when once fired is very little". Assuming I can single-fire my work--glazed and unglazed-- are you referring to the fuel cost specifically? Are you saying it takes just a little more fuel to fire the stoneware?



Lastly, point taken on the difficulty of working with porcelain. I had already ruled it out for now (in line with your comments). As my skills develop I may experiment later on.

Thanks a LOT,
Tom

#7 Chris Campbell

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Posted 04 June 2010 - 10:35 AM

Your enthusiasm is awesome!
What kind of 'hands on' clay classes have you taken?

There are a lot of good books out there.

Try calling The Potters Shop ... They have a huge ceramic book list ... tell them exactly what
you want to learn and ask for a recommendation.

Phone: 781-449-7687
Fax: 781-449-9098
Email: PottersShop@aol.com

Or head to your public library where you will find some of these books in the reference
section ... There are a lot of teachers and writers so it helps to find out who writes in
the way you understand. Some are down to earth technical and others are broader in scope.

As to the cost of the clay ...FORGET IT! Clay is the cheapest raw material around.
Think about it ... If you can't take a dollars worth of clay and make it into something
worth $5 then clay might not be for you.

You are at the start of a fabulous trip .... Enjoy!

Chris Campbell
Contemporary Fine Colored Porcelain
www.ccpottery.com

TRY ...   FAIL ...  LEARN ...  REPEAT


#8 Chris Clyburn

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Posted 04 June 2010 - 12:35 PM

Thanks for your helpful insights, Chris. I'm very process-oriented but ignorant regarding these technical issues. Can you (or anyone here) suggest an online primer or book I can consult in order to bring myself up to speed? Thanks for confirming the superior strength of vitrified stoneware vs. earthenware, especially when unglazed.

I'll have to look around and see what's out there online.
Some good books however are:
Daniel Rhodes: Clay and Glazes for the potter
Frank and Janet Hamer: The Potter's Dictionary of Materials and Techniques
Joe Finch: Kiln Construction: A brick By Brick Approach
Frederick Olsen: The Kiln Book
Emmanuel Cooper: 10,000 years of pottery

You caught me in the middle of a move, so all of my library is currently packed, this is just what I could remember, I know I'm forgetting some big ones here, but I can't think ...packing on the brain :-)


It sounds like stoneware at cone 6 might be optimal for me: suitable strength and durability at minimal temperature, with minimal fuel costs and (maybe) reduced kiln construction costs. I understand the gist, but would appreciate a clarification:

Q1. What does this mean, "...at a firing rate of 108F per hour during the final ramp"?

I think it describes a carefully monitored temperature change, but I don't understand the specifics. Clearly I need to study up, but appreciate any elaboration in the meantime.


This refers to the firing schedule used. Vitrification of ceramic ware is measured through the use of pyrometric cones (a combination of clay and glaze) that soften and bend at at precise points based on heatwork (a combination of time and temperature) Firings usually occur in stages also known as ramps. For instance a 4 ramp firing would be 100 F /hr to 200 F and hold the temp for 1 hour (or longer this is known as candling and helps dry out any remaining moisture in the clay). Then you'd be on the second ramp say 80 F/hr to 1100 THe third ramp would be 350 F to 1638F with the final ramp being 108 F to 1888. This final ramp is where the main measurement of heatwork occurs.

There are reasons for each stage. The first stage or ramp is just below the boiling temperature of water and drives of any remaining moisture without risk of steam expolsions. The second ramp is to burn of any remaining organics and allow any gas to escape, this is done slowly to ensure that there will be now little to no outgassing that will occur during the glaze firing which would cause defects in the glaze such as pitting. The third ramp is to get you to the last 250 Degrees below the final temp at which point it is fired at the rate needed to reach the final maturation temp with the proper amount of heatwork applied. I hope that clears it up.



Again I did not understand the significance of these issues. I thought a broad firing range was a 'pure benefit' because I didn't realize strength and color would vary based on firing temps within that range.... Duh.

Q2. So is this right? I need a STONEWARE CLAY BODY with a narrow firing range, that vitrifies nearly white at cone 6 or lower.

If I cannot find something that fires nearly WHITE, I could substitute two options instead: a gray (cool) and a buff/tan (warm).

Precisely



This kind of advice from someone who knows is most helpful. I'm "100% theoretical" at this point and I understand what a handicap that is.

Q3. I've read that in some cases bone dry paper clay can be glazed and fired in a single firing. Is that accurate? Are there special considerations or conditions?


Any clay can be glazed and fired in one go (known as once-fired) Things to consider are: The clay has to be bone dry, with absolutely no moisture. It should be fired relatively slowly, and you can significantly increase your risk of loss if not careful.


Q4. "The cost difference between earthenware and stoneware when once fired is very little". Assuming I can single-fire my work--glazed and unglazed-- are you referring to the fuel cost specifically? Are you saying it takes just a little more fuel to fire the stoneware?

Fuel cost specifically. It with a welll insulated kiln it does not take much more fuel to go from lowfire (below cone 1) to mid fire (cone 1-7) from low fire to hifire (up to cone 10) does use a significant amount of fuel.

#9 Chris Clyburn

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Posted 04 June 2010 - 12:41 PM

I would also add a caution:

Take a few ceramics classes before diving into building a kiln, and everything else.

Get a feel for it, and some hands on knowledge, especially of firing and how ceramic materials work. It is a very fun and rewarding field of study, (though not always financially rewarding unless you have a good head for business...as important or more so than being good at art). It is also very technically and physically challenging, especially when you are talking about architectural ceramics and large scale works. Start small and build a good foundation first, and you will thank yourself later :-)

#10 TBm

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Posted 07 June 2010 - 08:06 AM

Your enthusiasm is awesome! What kind of 'hands on' clay classes have you taken?

Just a pottery class (wheel and hand building) back in college. I'm long on enthusiasm and ideas. Short on experience.


Try calling The Potters Shop ... They have a huge ceramic book list ... tell them exactly what you want to learn and ask for a recommendation. Or head to your public library...find out who writes in the way you understand.


Small town. Small library with limited, old selection. Been there, done that.
I'll have to check The Potter's Shop per your suggestion. Thanks.


As to the cost of the clay ...FORGET IT! Clay is the cheapest raw material around.

Amen. I've made things from wood and from metal for years, but the rising price of both has pretty much shut that down. I set out to find a truly versatile sculpture material that's cheap and easy to come by. After a year's research, I've settled on clay, and maybe paper clay specifically.

The only hangup for me is firing. I really don't want a kiln (might be relocating soon, etc) and having to fire objects is both a big complication and a potential for problems. Also, I don't like marrying myself to a component (fuel) that may become extremely expensive, or entirely unavailable.

I WISH there were a "cold" process that would enable adding and subtracting from a form without having to 'cook' it afterward (I want a salad, not a stir fry, LOL). And reasonable kiln size is a severe limitation against working large-scale. But I've found no more-suitable material/process, so I'm focused on the possibilities for hand building, carving and molding paperclay. I hope it's as versatile and non-problematic as it seems based on my reading.


Think about it ... If you can't take a dollars worth of clay and make it into something worth $5 then clay might not be for you.

Agreed, as long as it doesn't cost $4 to glaze and fire it, LOL.


You are at the start of a fabulous trip .... Enjoy!

Thanks, Chris. I see how creative and successful your own approach is. I hope to find similar creative energy/opportunity.

#11 TBm

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Posted 07 June 2010 - 08:54 AM

Some good books are: (book titles here). You caught me in the middle of a move...

THANKS for the suggested titles. Moving is a very trying experience. Sorry to add to the complication.


This refers to the firing schedule used. For instance a 4 ramp firing would be 100 F /hr to 200 F and hold the temp for 1 hour (or longer this is known as candling and helps dry out any remaining moisture in the clay). Then you'd be on the second ramp say 80 F/hr to 1100 THe third ramp would be 350 F to 1638F with the final ramp being 108 F to 1888.

So ramps = stages. Okay. Am I reading you correctly per the following sequence?

1) RAMP 1: 100F/hr to 200F = 2 hours
2) hold the temp for 1 hour = 1 hour
3) RAMP 2: 80F/hr from 200F to 1100F = 11.25 hours
4) RAMP 3: 350F/hr from 1100F to 1638F = 1.5 hours
5) RAMP 4: 108F/hr from 1638F to 1888F = 2.3 hours

TOTAL FIRING TIME: approximately 18 hours


There are reasons for each stage...I hope that clears it up.

Thank you. Yes, I understand very well. YOU should write a book!


Any clay can be glazed and fired in one go (known as once-fired) Things to consider are: The clay has to be bone dry, with absolutely no moisture. It should be fired relatively slowly, and you can significantly increase your risk of loss if not careful.

Thanks for the warning. I'll study the subject in hopes of firing once to reduce time, expense and complication (though the "increased risk" looms heavy)


With a well insulated kiln it does not take much more fuel to go from lowfire (below cone 1) to mid fire (cone 1-7).
From low fire to hifire (up to cone 10) does use a significant amount of fuel.

I'm very glad you made the distinction between the low-to-mid fire range, and the much larger energy requirements involved in mid-to-high fire range. Based on this advice, I'll try to focus on stoneware at Cone 7 and below. Very useful information. As stated before, I'll seek
"STONEWARE CLAY BODY with a narrow firing range, that vitrifies nearly white at cone 6 or lower"


As for well-insulating a kiln firing no higher than cone 7, I'm imagining stacked refractory/fire brick (as the fiber blanket approach seems to be limited to lower temps). Is there some type of insulation that can be safely added to the outside of the fire brick walls/top to hold heat in? I know I'll have to study up, but would appreciate a short answer if you're aware of anything suitable.

#12 TBm

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Posted 07 June 2010 - 09:18 AM

I would also add a caution: Take a few ceramics classes before diving into building a kiln, and everything else.

I hear you loud and clear, and very much appreciate the wise advice.


Get a feel for it, and some hands on knowledge, especially of firing and how ceramic materials work.

...rewarding field of study
...not always financially rewarding unless you have a good head for business...as important or more so than being good at art
...very technically and physically challenging, especially when you are talking about architectural ceramics and large scale works.

Start small and build a good foundation first, and you will thank yourself later

I appreciate and take seriously every word. My problem is that I'm being squeezed by financial/economic pressures. I must choose a direction and GO! But as you point out, there are some very serious technical issues involved in this line of endeavor. As I stated above, I WISH I could find a suitable "cold process" (without these firing complications) but after searching for a year, I came up empty handed...

I don't have time for a lot of expimentation (the wolf is at the door) and the paperclay requires an additional SINTER firing to burn out the paper fiber prior to carving. At this early stage, I guess I'll have to have my work fired by others for a fee. But it'll be difficult to schedule my own unique "sinter firings" (and expensive, IF I can arrange it at all). So that pushes me toward building my own kiln, but the costs and the learning curve, etc are daunting, as you've pointed out. A real Catch 22. Hopefully I'll figure it out.

#13 CarlCravens

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Posted 07 June 2010 - 09:39 AM

Small town. Small library with limited, old selection. Been there, done that.
I'll have to check The Potter's Shop per your suggestion. Thanks.


Try Inter-Library Loan. It can take some time, and there's occasionally a small handling fee, but you can get nearly any book in the nationwide library system delivered to your library. I've got requests in for pottery books now. (My library is large, and has a pretty big selection of pottery books. But the selection is a little dated, and they don't have a lot of the books that get recommended.)

The only hangup for me is firing. I really don't want a kiln (might be relocating soon, etc) and having to fire objects is both a big complication and a potential for problems.


Where I live, there are at least two or three places that I can pay to have my work fired. The local pottery supply and one studio for sure, at least one other studio that I'd put bets on, and I could probably find six individuals that own kilns willing to fire my stuff for a fee. Unless you're out in the boonies, I expect you ought to find a few potters in your area... and if it *is* sparse, they'd probably welcome contact from a fellow clay artist.

I WISH there were a "cold" process that would enable adding and subtracting from a form without having to 'cook' it afterward


Epoxy. Certainly more limiting and expensive than clay, but miniature artists often work in green epoxy to sculpt their masters. You're not going to do large installations in epoxy, though. :)

If architectural installations are the goal and the material is open for exploration, have you considered sculpting in clay, taking a mold and casting in plaster or cement?
Carl (Wichita, KS)

#14 TBm

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Posted 07 June 2010 - 11:57 AM

Try Inter-Library Loan...you can get nearly any book in the nationwide library system delivered to your library.

I've never heard of that. Thanks for the idea, Carl. I'll stop in and ask the librarian.

Where I live, there are at least two or three places that I can pay to have my work fired...and I could probably find six individuals that own kilns willing to fire my stuff for a fee.

I've found three studios so far. One has several unvented electric kilns, so they don't want to fire paperclay. The other two have immense gas kilns, but it's impossible to pin those guys down on details (talking hypothetically, in advance). The answer to pretty much every question is, "It varies" which may be accurate, but makes it difficult to plan a strategy.

If architectural installations are the goal and the material is open for exploration, have you considered sculpting in clay, taking a mold and casting in plaster or cement?

Funny you should mention that <grin>. I have indeed considered those in my 'quest'. So far, cement is so heavy that transport costs/complications become serious drawbacks. The relative light weight of paper clay would be a big advantage. I saw some "countertop cement" at a local home store yesterday, though. Looks like it has potential...

Plaster is heavy too, but my real concern there is durability. It seems kinda delicate to me. And I'd like not to be boxed into casting only. I want the freedom to do high relief with undercuts, and flexible molds in large (or largish) scale seems expensive and perhaps not feasable.

I appreciate your suggestions and any further replies you care to make. I've been chasing my tail on this material/method search for months now. I'm dizzy enough without it.

#15 hansen

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Posted 08 June 2010 - 05:36 AM

I'm not visualizing this as working exactly the way as planned. These commercial clay bodies aren't going to give you a washable, durable, white, and rough and tumble surface for household or commercial interiors. With enough skill you could design that clay body however. Low fire will be ruled out completely, first of all. What you are alluding to is a fully, truly vitrified clay body, and that is going to be cone 10 and beyond. Once you have crossed that hurdle, then you are going to have to figure out how to fire these pieces with no warpage or distortion, a truly virtuoso feat in clay. I'm not sure why glaze is being ruled out. Glazes are harder and more durable, and more washable than exposed body clay. Glaze can look like anything, gloss, satin, matte, or even bone dry.

?????

h a n s e n

I'm in my Confused Early Stages, so please bear with me.

MY QUESTION
Should I choose a STONEWARE clay body such as Minnesota Clay MB STONEWARE
or a lower-fire EARTHENWARE?


BASIS FOR QUESTION:

LACK OF EXPERIENCE
I'm new to this and want to keep things as simple as possible.

INTENDED WORK PRODUCT
Tiles and larger flat forms involving relief sculpture - to be affixed to interiors of buildings as typical cermamic tile is. A kitchen backsplash, a fireplace surround, a segmented mural.

PAPER CLAY
I intend to use paper clay methods as much as possible.

KILN CONSTRUCTION and ENERGY COST ECONOMY
I hope to build a natural gas kiln. I want to limit energy costs and kiln construction costs as much as possible. Am I correct in thinking earthenware clays and related glazes fire at much lower temperatures than do stoneware clays. Will choosing an earthenware instead significantly reduce my firing costs and kiln construction costs? Any advice appreciated.

STANDARD of ABUSE
Finished product must withstand the knocks and scapes and washings that occur in any household. Imagine the abuse a doorframe suffers. In many instances, I will not employ a glaze. My work does not need to hold water (as vitirified clay can) but it will likely be washed with water and mild cleaning products occasionally - especially if a kitchen surface. Would an earthenware body stand up to houshold impact and washings, or must I opt for stoneware fired to vitrification?

WHITE
I want as white a clay body as possible. The MB Stoneware (per link above) fires nearly white in oxidation. Is there an earthenware that will meet the "abuse standard" described above and also fire nearly white in oxidation?


If my question is too broad, can someone please point me in the direction of an online source whereby I can educate myself further.

Thanks,
Tom




h a n s e n
Stone House Studio, Alexandria, Virginia

americanpotter.blogspot.com
thesuddenschool.blogspot.com

#16 TBm

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Posted 08 June 2010 - 12:10 PM

"?????"

This thread's most concise comment so far.
LOL


I'm not visualizing this as working exactly as planned.


Another gem, with a quality similar to, "Toto, I don't think we're in Kansas anymore..."
More LOL

h a n s e n, I truly appreciate your perspective and insights. You're right on the money, as are Carl and both Chrises. Thanks all, for helping me sort this out now, before I make costly mistakes.

These commercial clay bodies aren't going to give you a washable, durable, white, and rough and tumble surface for household or commercial interiors. With enough skill you could design that clay body however.

At present I'm resigned to working with readily available 'off the shelf' materials. Good point, though.

Low fire will be ruled out completely. What you are alluding to is a fully, truly vitrified clay body, and that is going to be cone 10 and beyond.


My instincts suggested exactly that, which is why I'm asking all these obtuse questions <grin>. I take your comments to mean: low fire will be ruled out and Cone 10+ will be required IF I require a washable, durable object that is NOT glazed. As I hope to fire at cone 6 or 7 max, your comments seem to indicate a need for glazing. Am I reading you correctly?


...then you are going to have to figure out how to fire these pieces with no warpage or distortion, a truly virtuoso feat in clay.

Admittedly my perspect is entirely 'book learned' thus far, based in part on reading Rosette Gault's Paper Clay: A Studio Companion for Sculptors. She advises that paper clay is particularly good at remaining flat during firing. I guess that may be a relative statement, depending on many factors, not the least of which is the size/length of the flat object to be fired(?)

For example, Gault suggests that a long flat object may be loaded into the kiln with its ends resting on two shelves and its middle spanning open space. She advises sprinkling sand on the shelves to enable the piece to shrink, unencombered by surface tension, etc. I have no expereince to confirm or deny such claims, and I would LOVE to hear from anyone who does.

You may laugh, but I hope to make flat objects as long as 7 FEET(!).
Am I completely delusional in that regard?


I'm not sure why glaze is being ruled out. Glazes are harder and more durable, and more washable than exposed body clay. Glaze can look like anything, gloss, satin, matte, or even bone dry.

Ahhhh, The PEARL of your post. ADMITTED FACT: I really need to research what is possible with modern glazes. I want to employ the appearance of unadorned, natural clay. My plan has been to glaze some surface areas--perhaps with a transparent wash or a clear glaze--and leave other areas unglazed (or perhaps just appearing unglazed, per your comments).

PLEASE ADVISE: Are you saying clear glazes are available
1) that are appropriate for Cone 6 firing of stoneware?
2) that would appear as though the object were not glazed, and in its natural state?
3) that would provide water-resistance and durability, hopefully in line with my plans?


If glazes are readily available that can accomplish all that, then I might be able to use a Cone 6 stoneware clay body. Yes?

Books on glazing and firing have already been recommended to me (thanks, all). If your answers to enumerated questions 1,2,3 above are all in the AFFIRMATIVE, I will have to start reading those books...

Thanks,
Tom


BIG FOLLOW-UP QUESTION Are there subtle glazes (or underglazes?) conforming to 1,2,3 above that could make a tan stoneware look like a white stoneware? If I could apply that, and then apply another glaze over it--to specific areas only--I think I might be on my way.




#17 Chris Campbell

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Posted 08 June 2010 - 05:20 PM

Peter king is well known for architectural ceramics ....

http://www.peterkingceramics.com/

You might want to read his book if you really want to be able to keep a seven foot long
piece straight and un-warped. Paper clay is all fine and good but you are still going to
need experience and skill to pull it off.

Chris Campbell
Contemporary Fine Colored Porcelain
www.ccpottery.com

TRY ...   FAIL ...  LEARN ...  REPEAT


#18 TBm

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Posted 08 June 2010 - 11:39 PM

Peter king is well known for architectural ceramics. You might want to read his book if you really want to be able to keep a seven foot long
piece straight and un-warped.

Paper clay is all fine and good but you are still going to need experience and skill to pull it off.

Experience and skill...and LUCK, it seems.

THANKS for the book suggestion. It's exactly on point. My planned work looks very different from his/hers, but the techniques will translate, I'm sure.

$80 for the book is pretty steep. When I get to the point where I'm going to try a seven-foot flat section, I'm sure $80 will look like money well spent (and how!). I'm looking carefully at their doorways, and I see where the cut lines are. Maybe this'll help me find a way to avoid such long lengths...

Thanks again for the link, Chris. Very instructive and very helpful. I'll be searching for more examples by both those artists .

Tom

#19 hansen

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Posted 10 June 2010 - 06:15 AM

whew - that is a bunch of questions - lets start out by talking about surfaces - underglazes and engobes and glazes are ADDITIVE surfaces. Wood fire is an additive surface which is ATMOSPHERIC. Salt and/or soda are SUBTRACTIVE surfaces which are ATMOSPHERIC and just might be the aesthetic "naked clay" look you are looking for - what happens here is the naked clay surface is being etched into and melted away, producing satin and matte ranges of surface -

if you want all these qualities in a cone 5-6 clay, some kind of mid-fire porcelain seems to be in order, but let me ramble on about glazes for a minute


but yes - it is all based on illusions, a glaze that looks like it is half an inch thick may only be 1/100th of an inch -

but also a glaze can look like naked clay just as easily as not (which is your intent)

and 7 foot forms are possible, I have seen sculpture, one piece, 8' x 4' x 4' -

and yes, a white surface can be applied to a non-white clay body and appear to be a white clay -

but the real crux here is durability, toughness, and hardness, in which case NICKLE and perhaps ZIRCONIUM might help -

a ZINC surface may have the look too - which gets you back into the glaze thing because these surfaces can be made really TOUGH

there are a lot of options, and at the investment level you propose, a lot of research involved. i hope this helps.

I don't have any experience with paper clay however - that's my disclaimer

maybe Matthew Katz has additional comments, can someone ask him to look at this -
h a n s e n




quote name='TBm' date='08 June 2010 - 12:10 PM' timestamp='1276017003' post='1011']
[quote name='hansen' date='08 June 2010 - 04:36 AM' timestamp='1275993365' post='999']
"?????"[/quote]
This thread's most concise comment so far.
LOL


[quote name='hansen' date='08 June 2010 - 04:36 AM' timestamp='1275993365' post='999']
I'm not visualizing this as working exactly as planned.[/quote]
Another gem, with a quality similar to, "Toto, I don't think we're in Kansas anymore..."
More LOL

h a n s e n, I truly appreciate your perspective and insights. You're right on the money, as are Carl and both Chrises. Thanks all, for helping me sort this out now, before I make costly mistakes.

[quote name='hansen' date='08 June 2010 - 04:36 AM' timestamp='1275993365' post='999']
These commercial clay bodies aren't going to give you a washable, durable, white, and rough and tumble surface for household or commercial interiors. With enough skill you could design that clay body however.[/quote]
At present I'm resigned to working with readily available 'off the shelf' materials. Good point, though.

[quote name='hansen' date='08 June 2010 - 04:36 AM' timestamp='1275993365' post='999']
Low fire will be ruled out completely. What you are alluding to is a fully, truly vitrified clay body, and that is going to be cone 10 and beyond. [/quote]
My instincts suggested exactly that, which is why I'm asking all these obtuse questions <grin>. I take your comments to mean: low fire will be ruled out and Cone 10+ will be required IF I require a washable, durable object that is NOT glazed. As I hope to fire at cone 6 or 7 max, your comments seem to indicate a need for glazing. Am I reading you correctly?


[quote name='hansen' date='08 June 2010 - 04:36 AM' timestamp='1275993365' post='999']
...then you are going to have to figure out how to fire these pieces with no warpage or distortion, a truly virtuoso feat in clay.[/quote]
Admittedly my perspect is entirely 'book learned' thus far, based in part on reading Rosette Gault's Paper Clay: A Studio Companion for Sculptors. She advises that paper clay is particularly good at remaining flat during firing. I guess that may be a relative statement, depending on many factors, not the least of which is the size/length of the flat object to be fired(?)

For example, Gault suggests that a long flat object may be loaded into the kiln with its ends resting on two shelves and its middle spanning open space. She advises sprinkling sand on the shelves to enable the piece to shrink, unencombered by surface tension, etc. I have no expereince to confirm or deny such claims, and I would LOVE to hear from anyone who does.

You may laugh, but I hope to make flat objects as long as 7 FEET(!).
Am I completely delusional in that regard?


[quote name='hansen' date='08 June 2010 - 04:36 AM' timestamp='1275993365' post='999']
I'm not sure why glaze is being ruled out. Glazes are harder and more durable, and more washable than exposed body clay. Glaze can look like anything, gloss, satin, matte, or even bone dry.[/quote]
Ahhhh, The PEARL of your post. ADMITTED FACT: I really need to research what is possible with modern glazes. I want to employ the appearance of unadorned, natural clay. My plan has been to glaze some surface areas--perhaps with a transparent wash or a clear glaze--and leave other areas unglazed (or perhaps just appearing unglazed, per your comments).

PLEASE ADVISE: Are you saying clear glazes are available
1) that are appropriate for Cone 6 firing of stoneware?
2) that would appear as though the object were not glazed, and in its natural state?
3) that would provide water-resistance and durability, hopefully in line with my plans?


If glazes are readily available that can accomplish all that, then I might be able to use a Cone 6 stoneware clay body. Yes?

Books on glazing and firing have already been recommended to me (thanks, all). If your answers to enumerated questions 1,2,3 above are all in the AFFIRMATIVE, I will have to start reading those books...

Thanks,
Tom


BIG FOLLOW-UP QUESTION Are there subtle glazes (or underglazes?) conforming to 1,2,3 above that could make a tan stoneware look like a white stoneware? If I could apply that, and then apply another glaze over it--to specific areas only--I think I might be on my way.



[/quote]



h a n s e n
Stone House Studio, Alexandria, Virginia

americanpotter.blogspot.com
thesuddenschool.blogspot.com

#20 hansen

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Posted 10 June 2010 - 06:21 AM

xx sagger
custer feldspar
talc
pv clay
EPK
Grolleg
flint
- they are all white, it's just a question of percentages, and of course, PAPER ?????
h a n s e n

[quote name='hansen' date='10 June 2010 - 06:15 AM' timestamp='1276168512' post='1032']
whew - that is a bunch of questions - lets start out by talking about surfaces - underglazes and engobes and glazes are ADDITIVE surfaces. Wood fire is an additive surface which is ATMOSPHERIC. Salt and/or soda are SUBTRACTIVE surfaces which are ATMOSPHERIC and just might be the aesthetic "naked clay" look you are looking for - what happens here is the naked clay surface is being etched into and melted away, producing satin and matte ranges of surface -

if you want all these qualities in a cone 5-6 clay, some kind of mid-fire porcelain seems to be in order, but let me ramble on about glazes for a minute


but yes - it is all based on illusions, a glaze that looks like it is half an inch thick may only be 1/100th of an inch -

but also a glaze can look like naked clay just as easily as not (which is your intent)

and 7 foot forms are possible, I have seen sculpture, one piece, 8' x 4' x 4' -

and yes, a white surface can be applied to a non-white clay body and appear to be a white clay -

but the real crux here is durability, toughness, and hardness, in which case NICKLE and perhaps ZIRCONIUM might help -

a ZINC surface may have the look too - which gets you back into the glaze thing because these surfaces can be made really TOUGH

there are a lot of options, and at the investment level you propose, a lot of research involved. i hope this helps.

I don't have any experience with paper clay however - that's my disclaimer

maybe Matthew Katz has additional comments, can someone ask him to look at this -
h a n s e n




quote name='TBm' date='08 June 2010 - 12:10 PM' timestamp='1276017003' post='1011']
[quote name='hansen' date='08 June 2010 - 04:36 AM' timestamp='1275993365' post='999']
"?????"[/quote]
This thread's most concise comment so far.
LOL


[quote name='hansen' date='08 June 2010 - 04:36 AM' timestamp='1275993365' post='999']
I'm not visualizing this as working exactly as planned.[/quote]
Another gem, with a quality similar to, "Toto, I don't think we're in Kansas anymore..."
More LOL

h a n s e n, I truly appreciate your perspective and insights. You're right on the money, as are Carl and both Chrises. Thanks all, for helping me sort this out now, before I make costly mistakes.

[quote name='hansen' date='08 June 2010 - 04:36 AM' timestamp='1275993365' post='999']
These commercial clay bodies aren't going to give you a washable, durable, white, and rough and tumble surface for household or commercial interiors. With enough skill you could design that clay body however.[/quote]
At present I'm resigned to working with readily available 'off the shelf' materials. Good point, though.

[quote name='hansen' date='08 June 2010 - 04:36 AM' timestamp='1275993365' post='999']
Low fire will be ruled out completely. What you are alluding to is a fully, truly vitrified clay body, and that is going to be cone 10 and beyond. [/quote]
My instincts suggested exactly that, which is why I'm asking all these obtuse questions <grin>. I take your comments to mean: low fire will be ruled out and Cone 10+ will be required IF I require a washable, durable object that is NOT glazed. As I hope to fire at cone 6 or 7 max, your comments seem to indicate a need for glazing. Am I reading you correctly?


[quote name='hansen' date='08 June 2010 - 04:36 AM' timestamp='1275993365' post='999']
...then you are going to have to figure out how to fire these pieces with no warpage or distortion, a truly virtuoso feat in clay.[/quote]
Admittedly my perspect is entirely 'book learned' thus far, based in part on reading Rosette Gault's Paper Clay: A Studio Companion for Sculptors. She advises that paper clay is particularly good at remaining flat during firing. I guess that may be a relative statement, depending on many factors, not the least of which is the size/length of the flat object to be fired(?)

For example, Gault suggests that a long flat object may be loaded into the kiln with its ends resting on two shelves and its middle spanning open space. She advises sprinkling sand on the shelves to enable the piece to shrink, unencombered by surface tension, etc. I have no expereince to confirm or deny such claims, and I would LOVE to hear from anyone who does.

You may laugh, but I hope to make flat objects as long as 7 FEET(!).
Am I completely delusional in that regard?


[quote name='hansen' date='08 June 2010 - 04:36 AM' timestamp='1275993365' post='999']
I'm not sure why glaze is being ruled out. Glazes are harder and more durable, and more washable than exposed body clay. Glaze can look like anything, gloss, satin, matte, or even bone dry.[/quote]
Ahhhh, The PEARL of your post. ADMITTED FACT: I really need to research what is possible with modern glazes. I want to employ the appearance of unadorned, natural clay. My plan has been to glaze some surface areas--perhaps with a transparent wash or a clear glaze--and leave other areas unglazed (or perhaps just appearing unglazed, per your comments).

PLEASE ADVISE: Are you saying clear glazes are available
1) that are appropriate for Cone 6 firing of stoneware?
2) that would appear as though the object were not glazed, and in its natural state?
3) that would provide water-resistance and durability, hopefully in line with my plans?


If glazes are readily available that can accomplish all that, then I might be able to use a Cone 6 stoneware clay body. Yes?

Books on glazing and firing have already been recommended to me (thanks, all). If your answers to enumerated questions 1,2,3 above are all in the AFFIRMATIVE, I will have to start reading those books...

Thanks,
Tom


BIG FOLLOW-UP QUESTION Are there subtle glazes (or underglazes?) conforming to 1,2,3 above that could make a tan stoneware look like a white stoneware? If I could apply that, and then apply another glaze over it--to specific areas only--I think I might be on my way.



[/quote]



[/quote]
h a n s e n
Stone House Studio, Alexandria, Virginia

americanpotter.blogspot.com
thesuddenschool.blogspot.com




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