An Overview of Home Cured Modeling Clays

An Overview of Home Cured Modeling Clays by: Eileen Bergen
http://www.theartfulcrafter.com
To my mind, modeling clay is one of the most fun media to “play”
with. From faux beads to small figurines to plaques to Christmas
ornaments to adornments for collages or scrapbook pages: every
crafter can find an application for clay. Home cured clays which
air dry or cure in the oven at low temperature are safe, easy
and one of the most affordable crafts around.
With a few basic shapes (ball, cane, pear, teardrop) you can
create almost anything. You can make clay molds; and then use
the molds to recreate a design over and over. You can stamp
impressions into clay; color it; texturize it; carve it. You can
make it look like almost any hard substance from stone to marble
to wood to bone.
I made an faux coral and jade bead necklace and earring set with
Sculpey III modeling clay, using an antique Chinese “Prosperity”
coin. The result, pictured on my site, looks quite authenic.
The choice of modeling clays and clay recipes is mind-boggling.
It helps to understand the differences in order to decide which
is suitable for your project.
I’ll narrow the field to general use modeling clays and exclude
the exotic types like rose petal clay, cinnamon applesauce clay
and coffee clay! That leaves three general categories: polymer;
cornstarch base; and bread base.
Polymer Modeling Clays The leading polymer clays are Sculpey and
Fimo. Pieces are cured in your home oven on low heat in just 15
minutes. Polymer clays have very long shelf life and are stored
simply by wrapping in plastic and keeping in a cool, dark place.
I’ve never had any harden in storage but if you do, there are
diluents to make the clay workable again.
The choices of colors and finishes (such as stone, glitter,
fluorescent and even glow in the dark) are wonderful.
The three main advantages of polymer modeling clays are: quick
home curing; the consistency and range of color and texture; and
the less than 2% shrinkage when cured.
Cornstarch Base Clays There are many variations of cornstarch
base clays. Some of the most popular are cold porcelain clay,
Victorian salt clay, and "pasta francesa".
I like the porcelain designation because cornstarch clays are
pure white and, if sealed after drying, they actually resemble
fine porcelain. They require cooking to prepare.
Cornstarch clays containing salt tend to be more porous than the
others. Cornstarch clays air dry; but drying can be accelerated
in a warm oven. The shelf life varies from one week to one month
depending on the ingredients, storage temperature and humidity.
Expect up to 30% shrinkage.
Bread Base Clays Bread base clays do not require cooking; they
air dry; and will keep up to three weeks in the refrigerator.
Shrinkage can be up to 50%. The “no cooking or baking required”
aspect makes bread clays the perfect choice for projects to do
with your kids.
As far as shrinkage goes, you can sometimes compensate by making
your project x% larger than you want the finished product. Keep
in mind that if you are making molds from which you will
recreate a design over and over, the amount of shrinkage to
expect almost doubles.
If you make a clay cast of a medallion that is 10mm in diameter,
a cornstarch base impression could dry as small as 7mm and the
medallions you make could be 4.9mm. If you use bread base clay,
the mold could measure 5mm and your clay medallions may be as
small as 2.5mm. That’s a big difference!
Visit http://www.theartfulcrafter.com/craft-ideas.html. I have
posted recipes and tips for bread and cornstarch clays, as well
as more articles and tips about polymer clays, such as Sculpey.
Eileen Bergen The Artful Crafter http://www.theartfulcrafter.com