The Many Uses
Polymer clays are plastic modelling compounds that come in many colors,
can be formed into any shape, and will bake permanently hard in a home
oven. They won’t dry out until they are baked hard (if properly stored,
kept cool and dark). They don’t shrink or expand--you can form them
over any bakeable armature or finding. Finished pieces can be drilled,
carved, sanded, or glued to backings (using a contact cement or epoxy).
Polymer clays are ideal for jewelry—pins, earrings, pendants—and
for figures, doll faces, and beads.
There are some differences in the properties of the different clays.
All must be manipulated a little, warmed and squashed in the hands,
to get the right working properties. Sculpey will be easier for children
and adult beginners. Cernit is somewhere in-between. Premo has a remarkable
plasticity, and hold detail very well while require little kneading
before use. Fimo Soft requires slightly longer kneading, but takes detail
better (it's much easier to use than the older version, now called "Fimo
Classic". They can be mixed to obtain a particular color or consistency
that pleases. Any clay that’s become too soft can be chilled or left
to sit a while.
Most modelers work mostly with hands, but needles (for piercing or scoring),
knives (to cut and carve), scrapers (for slicing), ceramic modelling
tools (for shaping), clay guns (for extruding shapes), pasta-makers
(for flat sheets) and other objects from around your house, will probably
assist your fingers. Work on a non-sticky surface—like waxed paper
or a piece of Plexiglas. There have lately appeared lots of helpful
books filled with carefully detailed technical and inspirational pictures.
Baking Times & Temperatures
Baking time and temperature are critical. The clay should fuse evenly
throughout and become a hard plastic. Too low a temperature, and it
crumbles; too high a temperature, and the outside fuses and burns before
the inside has cooked through. Manufacturer’s recommended cooking times
and temperatures vary, but 212½°F — 300°F mark
the outside temperature limits.
Sculpey does best at about 275°F, for 10 — 25 minutes,
depending on size, especially depending on thickness. Red and yellow
may darken too fast at this temperature, so use a cooler oven (say 265½°F)
for a little longer.
Premo should bake at 275°F, for 30 minutes per quarter
inch of thickness.
Cernit bakes at 215 — 270½°F, for about 30
Fimo will fuse properly at anything from 212-265°F, but lower temperatures
for longer times (as much as 30 — 40 minutes for beads) are best.
The “flesh” and translucent colors like lower temperatures.
If you're working with a mix, 265°F is a safe compromise. Or if
your blend is predominantly one brand, follow its instructions.
If your piece is still slightly soft, but you’re concerned that it may
darken or burn, take it out of the oven and let it cool. It will harden
some, and may need no further baking. If it does need longer, put it
back in for a few minutes. Your oven is probably hotter or colder than
the dial says; and some sections will be hotter than others. You may
want to check the actual inside temperatures with an oven thermometer.
It’s safer to bake for longer at a lower temperature, as long as the
clay gets hot enough to fuse. A toaster-oven is easier to use than a
full-size one, and it will heat up faster. If you work with polymer
clay a lot, a dedicated, out-door weather
Do not bake on a glass or metal surface. Use a wooden cutting board
(any flat piece of unfinished wood), or a ceramic plate or tile. Cardboard
is fine if you’re careful about temperature. Beads can be pierced with
(and baked on) wooden skewers. Hang beads or prop them up so they don’t
touch anything, and they won’t have unintended flat sides. Do not microwave.
Don’t breathe the fumes from baking polymer clays. Do not use knives,
trays, etc. for food once they've been used for polymer clay. When you're
done, wash hands well, with a nail brush or rough terrycloth.
Once baked, Sculpey has a matte surface, Cernit is porcelain-like, Fimo
is a little bit glossy. You can seal the finish with clear or matte
Sculpey Glaze, or with Fimo Varnish. Ordinary paste wax also works.
Or decorate and detail with acrylic paints.
CANEWORKING, VERY BRIEFLY
If you are around polymer clay much, you are bound to run into the term
“caneworking”. It is a borrowed glasswork technique, best known in the
Venetian “millefiori” trade beads. Polymer clay is vastly easier to
handle than glass, and incredibly elaborate and detailed designs are
Rods, or logs, or wedges, or sheets of clay in different colors are
arranged so that when they are joined into a solid mass, their cross-section
makes the desired design. Then thin wafers are sliced off, making many
(possibly hundreds) almost identical copies of the design.
Canes are generally built much larger than the slices will ultimately
be. They are then “reduced”, carefully rolled and patted till they are
much smaller, distorting them as little as possible in the process.
Slices can be made at any stage, yielding a range of sizes. They can
be thick or thin, free-standing or stuck to a surface. Geometric patterns
are easier, but - with patience and ingenuity - flowers, faces, animals
are all possible.