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Lesson Plans

Re: Clay Head Sculptures

[ Thread ][ Subject ][ Author ][ Date ]
Patricia Munce (pdmun)
Tue, 3 Jun 1997 00:30:23 -0800

Why clay projects blow up? My 15 years teaching ceramics experience is that:

1. Fired too soon. Let those puppies dry for days and days.
Steam leaving the clay blows them up. Cold to your cheek? Wait another
day or two.

2. Firing too fast, maybe.

3. Walls too thick, probably. Did you stick a long needle into the thick
sections to leave a canal for the air to leave in case of air bubbles?
Sorry, if this question sounds dumb, but I don't know your previous
experience in clay.

DIRECTIONS. I don't know why. We do the teaching right, why can't they do
the learning right?

Call your clay supplier and ask their advise on a good sculpture clay that
is very forgiving. Otherwise add some grog to the clay you are using now.
This will leave more spaces between particles, plus reduce shrinkage.

I use a "classic" terra cotta from the central valley of California which
is made about 15 miles from my school. They make outdoor planters out of it
and supply local sculptors like Margaret Hudson and Stan Bitters. It has a
coarse grog and fires brick red or brown, up to cone 5 max. You have to
work at it to get things to blow up even 3 inches thick. If the surface
appears too coarse, we make a clay slip from the clay and strain out the
coarse grog. Then we paint the layer of smooth slip over the sculpture for
a nicer smooth look. Burnishing helps too. All nice tricks to know. You
can do that with any clay, of course.

Hope this helps.

> My Introduction to Art students made clay sculptures this
>spring. Our school has another art teacher who has the kilns in her
>room. She fired the clay for us.
> ALL the clay heads in the Alpine kiln blew up! The majority of
>the heads in the electric kiln were fine. The color of the heads in the
>Alpine kiln was sort of gold, even brownish; the color of the fired clay
>heads in the electric kiln was basically white.
> A few weeks before the other teacher fired the example clay head
>I made; it came out perfectly. I used the same clay on the head I
>made; the walls of the clay head were about the same as those of most of
>the students. Three years ago my students did this project; most of the
>heads were fired successfully; I also had a similar experience several
>years earlier--they came out ok.
> Would you assume that the clay was fired to too hot a
>temperature in the Alpine? That the clay was fired too quickly--not
>candled...? I know it could not have entirely been because of the
>thickness of the walls of the clay, or mine would have blown up, too. I
>would like to avoid this problem in the future.
> The other teacher says that the problem was because they were
>all too thick; some of them probably were too thick.
> Any help would be appreciated.
> Thanks,
> Kay

Pat Munce

"We always have choices and
sometimes it's only a choice of attitude."