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terra-cotta slip for bisque?

updated sat 31 may 97

 

Cindy on sun 25 may 97

Centa,

Not sure what you want. A slip glaze using red low-fire clay for use in
glazing stoneware bisque? A coating to make white low-fire clay appear red?
Please elaborate.

I have painted white leather-hard stone-ware with brown stoneware slip, and
vice-versa. It works well when the clays are compatible, but you couldn't
apply the slip over bisque--it would flake off.

Cindy Strnad

centa uhalde on tue 27 may 97

>----------------------------Original message----------------------------
>Centa,
>
>Not sure what you want. A slip glaze using red low-fire clay for use in
>glazing stoneware bisque? A coating to make white low-fire clay appear red?
>Please elaborate.
>
>I have painted white leather-hard stone-ware with brown stoneware slip, and
>vice-versa. It works well when the clays are compatible, but you couldn't
>apply the slip over bisque--it would flake off.
>
>Cindy Strnad

Hi, Cindy,
Actually, I must preface my response by saying I'm pretty new at clay.
However, I am very enthusiastic and am taking classes in tile making as an
entry point. I also bought cheap a bunch of low fire white bisqueware, the
kind sold to Paint your own Pottery type places, from a woman quitting her
business. My plan is to experiment with it, primarily uisng the Majolica
technique. But, I like the look of the Majolica over terracotta clay. Maybe
it really doesn't matter and it's just my inexoperienced eye, but it seems
that the colors are richer and the tin glaze (or whatever white base glaze)
is more muted. SO, I have this idea to find a terracotta slip that can be
applied to this white bisqueware so that I can then dip it in the Majolica
and proceed. Make any sense?

Thanks,
Centa Uhalde

Cindy on wed 28 may 97

Centa,

Bisque is once-fired clay. Usually fired to a lower cone than the finished
piece, although this first firing may be higher than the final firing with
some low-fire glazes. Tony Hanson and others can give you more information
about firing specifics regarding majolica than I can.

You can't, to my knowledge, change the color after the bisque firing except
by glazing or painting the piece with oxides. If you buy a red/terra-cotta
slip and paint it over your work when it has dried to leather hard
consistency, this will likely produce the effect you're looking for. I
paint my slip on while spinning my pieces on the wheel for ease and
evenness of application. Naturally, this won't work for asymmetrical
pieces--you'll just have to paint them the best you can. Try for a smooth,
even coat.

Bagged, boxed terra cotta clay can be had for $10-$15/50# box at your local
ceramic/pottery supply house. You may want to consider starting out with
what you want to end up with. Especially for someone just beginning, this
might be the wiser route. Consider: you develop a library of techniques for
working with the white clay, making it appear to be terra-cotta, and then
you run out of white clay and it makes sense to buy real terra-cotta.
You've wasted a lot of time and effort. How much better to start with the
tools and materials you need from the very beginning. You can always find a
use for that white clay later on.

Buena Suerte,

Cindy