Elizabeth Canupp on thu 15 sep 05
I am making some tiles for my friend's new home. I
would like to use
a highfire clay--probably Soldate 60. I want to use
some very bright
colors for the glaze. When using a highfire clay with
lowfire glazes,
do I need to highfire the clay (after the bisque) and
then refire with
the lowfire glazes? Yes, I know this can be done but
from a technical
viewpoint, how durable will these tiles be if I don't
highfire?
I would use lowfire clay but I don't have the time nor
inclination to
experiment with lowfire (or any different clays) right
now.
Thanks in advance.
Waiting on "Ophelia."
Elizabeth Canupp
Virginia Beach, Virginia
Dave Finkelnburg on thu 15 sep 05
Elizabeth,
You have choices! :-)
It does sound like you understand the issues involved. In a non-freezing climate low-fired clay can be used, and it will survive, but for more durable work I would favor the body fired to a higher density.
You may want to simply "bisque" to glaze temperature (about cone 10 for your Soldate 60), then decorate and fire at the low temperature. This is how most twice-fired commercial porcelain is made. Just heating the tiles to help the glaze dry quickly will allow you to decorate them.
Glaze fit will be different on the porous tile than on the dense tile. I believe the hotter a clay body that contains quartz is fired to, the lower the coefficient of thermal expansion the clay body will have.
Good potting!
Dave Finkelnburg, hoping Ophelia just "grazes" the outer banks and swings back out to sea...
Elizabeth Canupp wrote:
I am making some tiles for my friend's new home. I
would like to use
a highfire clay--probably Soldate 60. I want to use
some very bright
colors for the glaze. When using a highfire clay with
lowfire glazes,
do I need to highfire the clay (after the bisque) and
then refire with
the lowfire glazes? Yes, I know this can be done but
from a technical
viewpoint, how durable will these tiles be if I don't
highfire?
__________________________________________________
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.com
Rick Hamelin on thu 15 sep 05
Dear Elizabeth
The first consideration that will answer your question is whether the tile is for use on the wall or on the floor.
Low fire glazes won't have the same durability for the floor as would high fire glazes. Secondly, the glaze interface, that is the layer of where the glaze and the ceramic meet would be superior for the floor but would be more than fine for the wall.
You should experiment with your low fire glaze on the non or low porous surface of the high fire tile to see if will not shiver or bead in the early stages of the firing.
Don't bisque your unglaze tiles only to refire them, unglazed, to stoneware temp. Bisque at high temp.
If you don't fire your clay to proper temp than it will be an inferior product. Not sarcasticly intended, but that is why we have three ranges of pottery, low, medium and high fire. Or earthenware, stoneware and porceslain. Not to mention the mid fire range.
You should test before your final run. Too many things to consider.
--
"Many a wiser men than I hath
gone to pot." 1649
-------------- Original message --------------
> I am making some tiles for my friend's new home. I
> would like to use
> a highfire clay--probably Soldate 60. I want to use
> some very bright
> colors for the glaze. When using a highfire clay with
> lowfire glazes,
> do I need to highfire the clay (after the bisque) and
> then refire with
> the lowfire glazes? Yes, I know this can be done but
> from a technical
> viewpoint, how durable will these tiles be if I don't
> highfire?
>
> I would use lowfire clay but I don't have the time nor
> inclination to
> experiment with lowfire (or any different clays) right
> now.
>
> Thanks in advance.
> Waiting on "Ophelia."
>
> Elizabeth Canupp
> Virginia Beach, Virginia
>
> ______________________________________________________________________________
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at melpots@pclink.com.
Snail Scott on tue 20 sep 05
At 08:28 AM 9/15/2005 -0400, you wrote:
>...When using a highfire clay with
>lowfire glazes,
>do I need to highfire the clay (after the bisque) and
>then refire with
>the lowfire glazes?
I would do the high firing. If there is going
to be no high-fire glaze, you can skip the
previous bisque - the high fire will BE the
bisque. Then apply the low-fire glazes, using
heat (or any of the other popular techniques)
to get the stuff to stick to the non-absorbent
vitrified clay.
Glazing vitrified clay is a pain, but applying
any glaze to a body which won't be matured is a
good way to get crazing, and more breakage than
normal.
-Snail
| |
|
