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


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#21 Denice

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Posted 10 June 2010 - 09:16 AM

[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

Dear Tom, I know you are on a tight budget but have you considered buying a electric test kiln, you can get one that plugs into a regular 110 outlet. They save you money in the long run especially when your experimenting with clays and glazes. When I graduated from Wichita State University Ceramic Program my professor Rick St.John recommended I get one. You can run all the test you want and not have to wait until you have a full kiln to add some test too. I know you plan to put in a gas kiln and the glazes won,t come out the same in the electric test kiln, put you might like the results of the oxidation firings. I can't get along without my test kiln, and if you don't use it you can always sell it.

Denice (Wichita, KS)

#22 Matt Katz

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Posted 10 June 2010 - 10:59 AM

What was the question?
I got lost in all that.

#23 TBm

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Posted 11 June 2010 - 01:08 AM

Dear Tom, I know you are on a tight budget but have you considered buying a electric test kiln..regular 110 outlet.

They save you money...especially when your experimenting with clays and glazes.

You can run all the test you want and not have to wait until you have a full kiln to add some test too.

I know you plan to put in a gas kiln and the glazes won,t come out the same in the electric test kiln, put you might like the results of the oxidation firings.

I can't get along without my test kiln, and if you don't use it you can always sell it.

Denice (Wichita, KS)

Thanks very much for that suggestion, Denise. In fact, I tried to buy a used electric kiln (approx 24' x 24" internal dimensions) locally as an interim solution, but was unsuccessful. I responed to Craig's List ads, but received either no reply or replies that refused to answer important questions. Eventually I did run across the "Test Kiln" concept as an alternative, though I haven't figured out who makes a good one at a fair price.

DO YOU HAVE ANY SUGGESTIONS?

In my 'natural state' (ignorance) my plan is to use a natural gas kiln for oxidation firing primarily - opting for gas mostly because it's less expensive to run and will let me construct my own unique kiln size to suit my needs. Certainly I don't know, but I'm hoping an electric oxidation firing will produce glaze results very similar to the same oxidation firing in a gas kiln... If so, the test kiln seems to be a GREAT idea.

Thanks, Denice,
Tom

#24 TBm

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Posted 11 June 2010 - 01:26 AM

What was the question? I got lost in all that.

Hey, Matt.

The #1 problem is that I ask TOO MANY QUESTIONS in a single post. They're all related to one another, and the combined answers do form a unified (albeit complex) strategy that helps me a lot. There really IS a Method to My Madness, but when I read this thread from the beginning, I too get slightly lost. But many, many thanks to h a n s e n for tackling my "tidal wave of ignorance".

The #2 problem is that some of us leave the entire quoted coments to appear in our replies. My posts are too long, containing multiple quotes and responses. When several other members reply to that, and each reply contains my entire multi-point preceding post...the thread becomes garbled and diluted. It's MY fault. Apologies to all.

So I hereby commit to asking one question per post.

And maybe others will commit to editing down the quoted comments that appear in their replies...?


Since I'm so interested in large-scale, architectural work, perhaps I should construct a ceramic Tower of Babble...(shakes head)
Tom

#25 bptakoma

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Posted 13 June 2010 - 07:30 PM

Tom,
Regarding carving tiles...You could make masters in regular clay (non-paper) and cast plaster molds from those for making paperclay tiles. Really, you could make masters in plasticine, or wood, or whatever. That gets you away from worrying about sintering prior to carving. Have to watch out for undercuts if you go that way.

7 foot span in one ceramic piece is a major stretch. Perhaps better to cast those in concrete or learn stone carving!

There are varieties of plaster that are pretty durable if you're looking at decorative, but not structural.

#26 TBm

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Posted 13 June 2010 - 09:52 PM

You could make masters in regular clay (non-paper) and cast plaster molds from those for making paperclay tiles...masters in plasticine, or wood, or whatever. [avoid] worrying about sintering prior to carving...watch out for undercuts.

7 foot span in one ceramic piece is a major stretch. Perhaps better to cast those in concrete or learn stone carving!

There are varieties of plaster that are pretty durable if you're looking at decorative, but not structural.

bptakoma ==
How nice to hear from Takoma Park, Maryland! I used to live not far from there before relocating to dead center of the nation (which really is quite lively as it turns out). I hope Takoma Park still has its enclaves of quirkiness. Years ago I recall driving one short stretch of road that designated that neighborhood a "nuclear free zone." I used to chuckle then, and I am again, while typing this. Takoma Park is an interesting place.

Good points all. I like your suggestion for carving masters in regular clay, and then press molding paper clay tiles.

QUESTION: Can you point me in the direction of information on "durable plaster" - not structural, but perhaps something that might be durable to the extent that softwood moldings, door and window casings, etc are?

Thanks,
Tom

#27 hansen

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Posted 17 June 2010 - 05:02 AM

Matte glazes, while appearing to be under-fired clay-like surfaces, are often matte due to surface crystalization on a very minute scale, but are actually very fluid and sufficiently fired surfaces. Wood ash and high barium surfaces come to mind for a dry look. as does zinc and magnesium. The secrets of ceramics don't come easy. Network with some people. I listed the white stuff available from the supplier.

Who knows? Maybe a white clay mixed with a % of talc is all you need. Your demands and designs are unique to you as a person your ability to research the information will determine whether or not you succeed more than anything else.

Clay=bones, engobes=flesh, glaze=skin

bones, flesh, skin

h a n s e n


[quote name='hansen' date='10 June 2010 - 06:21 AM' timestamp='1276168871' post='1033']
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]
[/quote]
h a n s e n
Stone House Studio, Alexandria, Virginia

americanpotter.blogspot.com
thesuddenschool.blogspot.com

#28 TBm

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Posted 17 June 2010 - 09:41 AM

h a n s e n ==

Thanks for the additional information.

QUESTION: Can matte glazes create that "dry look" in an oxidation firing? I want to avoid reduction methods at first, in part because I may have to use an electric kiln initially...


(Humble suggestion to all: don't quote long posts [absurdly long quotes, in my case] in your own illuminating replies. It makes the thread unnecessarily long and visually confusing, thereby obscuring the gems of information you contribute. Just delete unnecessary quoted content before typing your own comments. Merely a suggestion in the interest of effectively communicating so much EXTREMELY HELPFUL information)


Tom

#29 Matt Katz

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Posted 21 June 2010 - 08:56 AM

Matte glazes are ALWAYS based on chemistry and not firing. Anything that appears matte yet is unpredictable is under fired and not matte.

h a n s e n ==

Thanks for the additional information.

QUESTION: Can matte glazes create that "dry look" in an oxidation firing? I want to avoid reduction methods at first, in part because I may have to use an electric kiln initially...


(Humble suggestion to all: don't quote long posts [absurdly long quotes, in my case] in your own illuminating replies. It makes the thread unnecessarily long and visually confusing, thereby obscuring the gems of information you contribute. Just delete unnecessary quoted content before typing your own comments. Merely a suggestion in the interest of effectively communicating so much EXTREMELY HELPFUL information)


Tom



#30 Marcia Selsor

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Posted 09 July 2010 - 06:49 AM

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



That is way more than one question. You need to figure out a lot.
1. why build a natural gas kiln if you are going to do low fire oxidation?
2. Gas flames tend to warp flat tiles. Oxidation is more gentle for not warping because of the radiant heat.
3. You should fire your clay to vitrify if you want it to withstand bumps and household abuse. Otherwise it will be soft and weak.
4. earthenware fired to vitrification is hard and durable.
Here is some recommended reading from my Architectural ceramics workshop handouts:
Recommended Reading On Architectural ceramics:

Thames and Hudson Manual of Architectural Ceramics by David Hamilton

Architectural Ceramics by Peter King

Architectural Ceramics; Eight Concepts

Large Scale Ceramics by Jim Robinson

Handmade Tiles by Frank Giorgini

Terra Cotta Skyline by Susan Tunick

PARIS and the Legacy of French Decorative Ceramics by Susan Tunick

American Decorative Tiles by Susan Tunick

On Technical details:

Setting Tiles by Michael Byrne

Working with paper Clay and other Additives by Anne Lightwood

Shape and Surface by Lana Wilson

Ceramic Glazes by Cullen Parmelee

Elements of Ceramics by F.W. Norton

The Extruder Book by Darryl Baird

Other Resources

Friends of Terra Cotta

Tile Heritage







#31 bptakoma

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Posted 20 July 2010 - 02:07 PM

How nice to hear from Takoma Park, Maryland! I used to live not far from there before relocating to dead center of the nation (which really is quite lively as it turns out). I hope Takoma Park still has its enclaves of quirkiness. Years ago I recall driving one short stretch of road that designated that neighborhood a "nuclear free zone." I used to chuckle then, and I am again, while typing this. Takoma Park is an interesting place.

Good points all. I like your suggestion for carving masters in regular clay, and then press molding paper clay tiles.

QUESTION: Can you point me in the direction of information on "durable plaster" - not structural, but perhaps something that might be durable to the extent that softwood moldings, door and window casings, etc are?

Thanks,
Tom
[/quote]

Tom,
If you want plaster, research architectural ornamentation plasters, like Hydrocal. Here's a link to get you started. http://www.gypsumsolutions.com/

We are still running quirky and strong in Takoma Park. And yes, still nuclear free. Actually, that doesn't mean you can't have a nuclear family, or get an xray, or transport nuclear weapons through the town. What it does mean is the city cannot by products from companies involved in the manufacture of nuclear weapons. My town is big on following it's principles! The effect is they have to get a waiver from the nuclear free advisory board (or some such) to buy a GE lightbulb for city hall.

There have been suggestions on going gas-powered lawn mower free and meat free. Perhaps not in the near future. I still enjoy living somewhere where I feel like a solid moderate. Oh, and the city is excellent with plowing the roads in winter time. It's the only place I've ever lived that I can say that about.

Cheers,
Beth




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