Harrington on wed 25 sep 02
Greetings gentle clay folk.
Since I picked up pottery as a hobby, I've become interested in trying
out firing my sculptures instead of casting them. So I did. I just
opened the kiln, and the results are OK, but a few things are perplexing
for me, an inexperienced firer.
The first sculpture is a torso, about 15 inches high, walls about 3/4
inch thick. I modeled it on an armature, made a poylsulfide mold just to
be on the safe side, and then cut it in half, hollowed it out, stuck it
back together again, and let it dry for about 6 weeks. It is made of
Standard 181 white stoneware, with no fireclay or grog.
The second sculpture is a lifesized (or at least it was, before
shrinkage) portrait head. In this case, I made the head using a latex
mold I had made for casting. I simply opened it up and used it like a
press mold, smushing clay into both sides and joining them together. The
walls are about 1/2 to 3/4 inches thick. After rejoining them, I had a
lot of work to do to make the surface acceptable. It is made of Byrne
Red Stoneware with fireclay.
So here's what happened. I put them in my digital electric kiln
together, punched in cone 6, set it on slow, and let 'er rip. Today I
opened the kiln at 126 degrees F., and took out the torso. On the
outside it is flawless, creamy white. Looks great. On the inside,
however, it has a lot of cracks. Why? Is it because the clay on the
outside was very compressed? Maybe it has something to do with the
drying process? Anyway, since it looks good on the outside, I want to
use it. Should I repair the cracks? What would I use? I've heard maybe
Durham's Rock Hard Water Putty might be good. Any ideas?
The portrait head is a little weirder. It has some small hairline cracks
in the face. Also, instead of a nice, uniform red, it has a sort of
charred look on the face and top of the head, like maybe it burned. Why?
Also, the fireclay, which turns out to be white, is very visible on the
surface, giving my lovely girl a shocking case of acne. Is this normal?
Since the color is so crummy, I guess I'd like to repair the cracks and
cover the whole thing with a faux bronze patina. Does anyone know how to
do that?
Maybe I should have used earthenware? Your feedback is greatly appreciated!
Lisa
| |
|
