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TBm

Member Since 04 Apr 2010
Offline Last Active Jun 18 2010 01:34 PM
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Topics I've Started

Vitrified Stoneware Strength: Cone 10 Vs.cone 6

04 June 2010 - 09:34 AM

GIVEN:
- Stoneware A has a broad firing range, Cone 6 - 10
- Stoneware B has a narrow firing range, Cone 5 - 6

I take that to mean the following:
- A vitrifies fully at cone 10
- B vitrifies fully at cone 6


QUESTION:
Is A at cone 10 more vitrified (and stronger) than B at cone 6?
Or are they basically equal in terms of vitrification and strength?

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

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

Natural Gas Kiln: Cheaper To Run Than Electric?

02 June 2010 - 03:09 PM

Hi, all.

I expect to build my own odd-sized kiln (after I work out many details), and am told that it is possible to build DIY either a natural gas kiln or an electric kiln... If building an electric kiln is not really feasable, please warn me off now, before I dig myself a hole (which is my 3rd kiln option, LOL).

Hypothetically:

- Kiln A is a long, low cross-draft natural gas kiln 4'W x 4'H x 8'D.

- Kiln B is an electric kiln of the same dimensions.


Firing both to Cone 10, can someone give me an idea of how the costs would compare?
Here's a rough idea of my current rates:
Electric kWH = $0.07 summer and $0.09 winter
Natural Gas = $0.85 per therm

Any advice much appreciated,
Tom

Paper Clay Forum, Here Or Elsewhere?

02 June 2010 - 10:00 AM

I just finished reading Rosette Gault's book, Paper Clay for Ceramic Sculptors: A Studio Companion.
The latest edition contains helpful insights, but lots of questions were left unanswered.

Is there a Paper Clay forum here at CAD that I 've overlooked? If not, can someone suggest an energetic/active forum elsewhere?

I'm not referring to Sculpey classroom clay products. I'm interested in adding cellulose fiber to stoneware claybodies.

Thanks,
Tom

Grinding & Drilling Methods For Fired Stoneware?

07 April 2010 - 12:39 AM

Hi, all ==

My first post here. I'm an aspiring sculptor drawn to ceramic/clay because of its versatility.

I would like to know if there are accepted (and safe) methods for drilling into stoneware that is already high fired (cone 10). I'd also like to know if there is a method for grinding straight, flat edges into fully fired stoneware objects.

I have wood working experience, where drill press and table saw solve these problems easily. But clay shrinkage and the potential for airborne silica make ceramic solutions more challenging.

EXAMPLE illustrating what I want to do:
Imagine a picture frame made of fired stoneware, into which I will set a mirror from behind. a) I want to create an accurate rabbet, a ledge or channel cut into the back side of the frame to accommodate a precut mirrored glass (I imagine a grinding operation would form the rabbet). I also want to drill accurately-sized holes into the back of the frame for inserting hanging apparatus.

I realize I could cut the mirrored glass after firing the clay, so the glass would accommodate the post-shrinkage size of the frame opening. But I have other projects in mind that will need to be resized accurately, and with particularly straight edges. I also envision the need for holes of accurate diameter, which to my mind, involves drilling after final firing.

Any advice is much appreciated,
Tom