vince pitelka on sun 26 nov 00
> I would think the firing temp of the terra cotta would cone
> 04 at the highest and would likely be lower than that.
> These surfaces do not appear glassy . were they vitrified glaze
> surfaces or porous?
Stephani -
For architectural terra cotta, cone 04 would be a very low firing
temperature, and I doubt that the results would stand up to the weather. If
you have ever seen any examples of architectural terra cotta, it is very
dense and hard, almost vitrified. The same is true of older red brick. You
would not expect such a product to be glassy at all, because then it would
slump and bloat in firing, and the finished product would be very brittle.
The surface of architectural terracotta is still slightly porous where it is
not glazed, but it is far denser than your average terracotta flower pot.
Best wishes -
- Vince
Vince Pitelka
Home - vpitelka@dekalb.net
615/597-5376
Work - wpitelka@tntech.edu
615/597-6801 ext. 111, fax 615/597-6803
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
http://www.craftcenter.tntech.edu/
Snail Scott on sun 26 nov 00
>Date: Sun, 26 Nov 2000 13:05:21 -0800
>To: mudmistress@earthlink.net
>From: Snail Scott
>Subject: Re: Terra cotta / historical
>In-Reply-To: <3A216583.57A81E56@earthlink.net>
>References: <3A203DCA00000408@mail.acers> (added by mail.acers)
>
>
>The architectural terra cotta I have seen is often glazed
>to resemble stone, which was considered much classier than
>clay. The underlying clay, often buff-colored, appears to
>be fairly high-fired, and not very 'earthenware-looking'.
>I have seen books about such historical works, but most of
>them have more pretty pictures than technical information.
>
>Next time I visit the Gladding MacBean factory I'll ask more
>questions! (They made much of the architectural terra cotta
>around here, and are still in the business.) Their annual
>tour in conjunction with the Feats of Clay exhibition is
>very cool, indeed. Almost no modernization at all, but still
>a viable large-scale manufaturing operation. (mainly sewer
>pipe, nowadays, but not entirely.) They are in northern
>California, near Sacramento.
>
>A nice book I acquired lately is "Terra Cotta Skyline" by
>Susan Tunick. It's more history than technique in
>its approach, and deals mainly with New York and the East
>Coast of the U.S., but has a lot of information about the
>designers and manufacturers, and about the historical
>development of architectural terra cotta. Published by
>Princeton Architectural Press, 1997, ISBN 1-56898--105-8.
>A very elegant book, definitely gift-grade for the interested.
>
>Peter King's book "Architrectural Ceramics" is a great resource
>for technique, although I suspect his methods work better in
>Florida than in the desert!
> -Snail
>
>At 11:33 AM 11/26/00 -0800, you wrote:
>
>>One other question comes to mind. Often terra cotta building facades
>>from the late 1800s early 1900s were made to look like stone. Does
>>anyone have any knowledge about how this was done ? Were these glazed
>>surfaces? I would think the firing temp of the terra cotta would cone
>>04 at the highest and would likely be lower than that.
>>These surfaces do not appear glassy . were they vitrified glazed
>>surfaces or porous?
>>Anyone have a clue or know of a good resource?
>>
>>Stephani Stephenson
>>Leucadia CA
>>
>
Frank Gaydos on sun 26 nov 00
I understood that outside terracotta tile was often fired around cone 1. Not
sure how I got that impression however.
-----------------------------------------
I would think the firing temp of the terra cotta would cone
04 at the highest and would likely be lower than that.
These surfaces do not appear glassy . were they vitrified glaze
surfaces or porous?
Anyone have a clue or know of a good resource?
Stephani Stephenson
Leucadia CA
Marcia Selsor on mon 27 nov 00
Dear Stephanie,
I usually fire architectural terra cotta pieces to ^2. This brings out
the rich browns.
If I am using a tin glaze on pieces and they are not planned for outside
than I fire to ^03.
See attached photo.
As for recommended books. I like this gem:
Thames and Hudson Manual for Architectural Ceramics. It is full of
technical information for the studio potter up through low tech industry.
> > I would think the firing temp of the terra cotta would cone
> > 04 at the highest and would likely be lower than that.
> > These surfaces do not appear glassy . were they vitrified glaze
> > surfaces or porous?
> Best Wishes,
Marcia
--
Marcia Selsor
selsor@imt.net
http://www.imt.net/~mjbmls
http://www.imt.net/~mjbmls/Tuscany2001.html
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