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is salt fire always high fire?

updated mon 30 jun 97

 

McCoy, Jack Eugene on sat 17 may 97

I've always assumed that salt firings require high temperatures (cone
9-10).
Is this true or can salt be used at lower temps?

Thanks,
Jack

Brooks Burgess on sun 18 may 97

At 10:36 AM 5/17/97 EDT, you wrote:
>----------------------------Original message----------------------------
>I've always assumed that salt firings require high temperatures (cone
>9-10).
>Is this true or can salt be used at lower temps?
>
>Thanks,
>Jack
>
>salt can be used to flash terra sig at low temps. salt can be used at the
maturing temp of the clay body.

Laurie Force on sun 18 may 97

On Sat, 17 May 1997, McCoy, Jack Eugene wrote:

> ----------------------------Original message----------------------------
> I've always assumed that salt firings require high temperatures (cone
> 9-10). Is this true or can salt be used at lower temps?
------------------
Jack, I'm about to participate in a low-firing techniques class at our
college which includes salt-bisquing. So yes, you can.

Laurie in Grand Junction

Jack Troy on mon 19 may 97

It depends whether you want a true _glaze_, or a patina flashed onto the body,
but not interacting with it to the degree that a glaze does.
Salt was at one time fluxed down with borax to make a true glaze on a body
formulated to accept it in the c/04 range. It was a method employed by the
ceramics industry to make such things as acid-resistant building materials
especially for silos, of which many survive. There's even one entire house
built of salt-glazed building blocks, on the south side of Route 80 between
Clearfield and Clarion, PA. It may not be worth a 500+ mile field trip to see,
but it's worth looking for if counting trees along that stretch of highway gets
to be boresome.
Jack Troy

Dannon Rhudy on tue 20 may 97


That is really intersting, Jack. I have seen silos made of some
ceramic material in rural southern Indiana, and know of at least
two tiny (3-room, probably) houses tucked back into the folds of
the hills, made of the same material. At least, it looks the same
and is ceramic of some kind. Maybe next trip I'll brave the
hound pack(s), knock on a door or two, learn something.

Dannon Rhudy
potter@koyote.com

----------------------------Original
message----------------------------
It depends whether you want a true _glaze_, or a patina flashed
onto the body,
but not interacting with it to the degree that a glaze does.
Salt was at one time fluxed down with borax to make a true glaze
on a body
formulated to accept it in the c/04 range. It was a method
employed by the
ceramics industry to make such things as acid-resistant building
materials
especially for silos, of which many survive. There's even one
entire house
built of salt-glazed building blocks, on the south side of Route
80 between
Clearfield and Clarion, PA. It may not be worth a 500+ mile field
trip to see,
but it's worth looking for if counting trees along that stretch of
highway gets
to be boresome.
Jack Troy

Gavin Stairs on fri 23 may 97

At 10:36 AM 17/05/97 EDT, you wrote:
>----------------------------Original message----------------------------
>I've always assumed that salt firings require high temperatures (cone
>9-10).
>Is this true or can salt be used at lower temps?

Salt fumes at lower temperatures, but you may produce more undesirable
gases then, too. True boiling only occurs at cone10 and above. Salt
glazes and salt included in saggers may produce noticeable effects well
below cone 10.

Gavin
=================================
Gavin Stairs
http://isis.physics.utoronto.ca/

"Rafael Molina-Rodriguez (Rafael Molina-Rodriguez)" on sun 1 jun 97

Gavin :

>Salt fumes at lower temperatures.

I'm in the process of building a miniature variation of an MFT kiln (
approx. 9 cu. ft. ) here at the college to work with salt at lower
temperatures. I was inspired by the recent work of Paul Soldner and a local
potter Mark Epstein. The research I've done indicates they both fire in the
^ 010 range.

Soldner has employed the low fire salt process for his recent sculptures.
Mark Epstein did a body of work for his M.A. show at the University of
Dallas a few years ago with very interesting results. Apparently, the salt
fuming at this temperature creates shades of pink, orange, and burgundy.

>salt included in saggers may produce noticeable effects well below >cone
10.

Indeed, they do. In the past, I fired my wheel thrown, burnished porcelain
vessels in saggars with sawdust, salt, and hay soaked in salt water to ^
010. The salt flashed onto the white clay turning it shades of pink and
orange.

I also soda fire below cone 10. I fire to ^ 7. The claybodies, slips,
stains, and glazes we use mature at this temperature. I fire to the peak
temperature then introduce the soda solution. After five years the kiln is
well seasoned. It only takes two pounds of soda ash in one gallon of water
to achieve the desired effects. I measure the effects of the soda by using
draw rings.

Rafael
rmr3431@dcccd.edu