Protecting overbaked parts

A Cernit horse sculpture was left in the oven too long, perhaps an
hour.

The white Cernit has yellowed, and there are tiny lines/delicate
cracks on parts of the head. The lines/cracks are really tiny and
would probably not be visible through a coat of paint. They're maybe
1/4 inches long.

The sculpture isn't finished yet, so it will need to be baked again.
Any tips on protecting/insulating the overbaked parts? Any ideas as to
how bad the current condition is? Can you safely re-bake yellowed
Cernit, or is all lost?

| On 13 Apr 2004 05:03:32 -0700, (Henrik N) wrote:

A Cernit horse sculpture was left in the oven too long, perhaps an
hour.

The white Cernit has yellowed, and there are tiny lines/delicate
cracks on parts of the head. The lines/cracks are really tiny and
would probably not be visible through a coat of paint. They're maybe
1/4 inches long.

The sculpture isn't finished yet, so it will need to be baked again.
Any tips on protecting/insulating the overbaked parts? Any ideas as to
how bad the current condition is? Can you safely re-bake yellowed
Cernit, or is all lost?

I don't often work with Cernit, but this is what I might do in your place.
I'd coat it with a thin layer of translucent or white liquid sculpey
before re-baking. That cures better at a little higher temperature so I
probably would not shield that area with foil for that bake. The liquid
sculpey will fill the cracks and strengthen the item. You will still have
to paint to hide the yellowing, if you use the translucent. The white will
mask the yellowing like a coat of gesso would.

For future work, I would suggest tenting thin work with foil during baking
and starting in a cold oven. I routinely bake thin Premo items for an hour
in a toaster oven set at 275F. I use its tray lined with cardboard. I have
a sheet of foil tucked under the cardboard along one long side so I can
just lift it up to place items, then bring the tent down for baking. This
tray also has a thermometer tucked under the opposite edge of the
cardboard, where I can see it through the oven door. I start in a cold
oven. Bake for an hour, then turn the oven off and do not take anything out
until the thermometer gets under 100F, usually well under. This oven heats
slowly, though, so the actual time at 275F is about 40 minutes.

Worse comes to worst, if the piece ends up looking ugly but the shape is
still good, you might make a mold of it so you don't have to start over
from scratch.

Helen "Halla" Fleischer, Fantasy & Fiber Artist
http://home.covad.net/~drgandalf/halla/
Balticon Art Program Coordinator http://www.balticon.org

Wrap or drape damp paper towels on the pre-baked parts.
This technique also helps to protect smaller or thiner components of an
unbaked sculpture. I'm partial to Viva paper towels as they have almost
no texture and are durable, good for multiple uses.

Hope this helps,
Katherine Dewey
http://www.elvenwork.com

Henrik N wrote:

A Cernit horse sculpture was left in the oven too long, perhaps an
hour.

The white Cernit has yellowed, and there are tiny lines/delicate
cracks on parts of the head. The lines/cracks are really tiny and
would probably not be visible through a coat of paint. They're maybe
1/4 inches long.

The sculpture isn't finished yet, so it will need to be baked again.
Any tips on protecting/insulating the overbaked parts? Any ideas as to
how bad the current condition is? Can you safely re-bake yellowed
Cernit, or is all lost?