Kat in the Hat on thu 27 may 04
Joyce said:
>That was yesterday. 24 hours later I take the
>slabs out..... they're not dry by any one's
>estimation ..... but the parts that ARE dry are
>on the surface ...... sort of a powdery dryness...
>talcy to the touch... but damp beneath. AND
>there are small cracks around the perimeter of
>the slabs even though I smoothed them with
>my fingers and a brayer ... with longer cracks
>running from the
>edges into the center where the stamped images
>are. The cracks do not cross over the little
>ridge around the images....... just run up to
>them. It's almost as if the images were designed
>to have the slab break away like a coupon may
>be folded and torn off from a page evenly.
I have never worked with Southern Ice, but have used other
translucent porcelains. What I did note about your comments
was that the pieces were not dry - but parts that ARE dry
are powdery, etc... Did you cover them up with plastic?
Porcelain requires extra attention to drying, the important part
is "even" drying. Meaning if areas are dry and other areas are
not obvious tension in the shrinkage rates are creating the cracks.
Perhaps they stop at the stamped areas because those areas are
more compressed. Southern Ice may not be the clay to use for
the type of process you are using. Just a thought.
Kat
kat@digitalfire.com
Lois Ruben Aronow on fri 28 may 04
> Porcelain requires extra attention to drying, the important
> part is "even" drying. Meaning if areas are dry and other
> areas are not obvious tension in the shrinkage rates are
> creating the cracks.
> Perhaps they stop at the stamped areas because those areas
> are more compressed. Southern Ice may not be the clay to use
> for the type of process you are using. Just a thought.
It's especially important, when drying porcelains, that your form is evenly
trimmed. A thick foot and a thinner bottom will result in cracking, as will
a thin foot and a thicker wall. Porcelains require much more skill than
just the throwing.
* * * * * * *
Lois Ruben Aronow
Modern Porcelain & Tableware-Updated for Spring 2004!
www.loisaronow.com
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