What is Polymer Clay?:
Polymer Clay is an oven baked modelling compound, widely used to sculpt dolls house miniatures and food, scale dolls and figures, and scale models. A form of Poly Vinyl Chloride,it remains workable until cured by baking at the specific temperature recommended for that particular brand of clay. Various brands of clay have different handling and finish properties. Clay brands are often chosen by what type of work you want to achieve with the clay. Stiffer clays are generally used for forming repeated patterns which are cut as slices from canes. Softer clays are used for modelling and blending sculptures.
Check the list of polymer clay brands for reader reviews and recommendations.
Polymer Clay is certified as non toxic but is not edible and should not be worked near food or with food utensils. Use clay specific tools when working with polymer clay.
Clay brands should carry the ASTM D4236 designation, meaning that it can be handled safely by artists of all ages. Work with the clay can provoke allergies in some people, you may want to consider using artist’s barrier creams or gloves.
Always clean your hands well after working.
Sanding polymer clays or using metallic powders, should be done with a proper dust mask in a well ventilated area.
Curing Polymer Clay:
These clays must be baked to set. In the baking process they can give off fumes. Always bake the clays with adequate ventilation and follow the temperature guidelines for your particular brand of clay. Do not overbake or burn the clay. If this happens immediately ventilate the area. These clays are not safe for the microwave.
If you intend to bake large amounts in your regular oven, you may want to enclose the clay to avoid the buildup of any residue on the walls of your oven. To do this enclose the clay in a covered pan, or set the tile you bake your items on inside a sealed oven roasting bag.
Handling and Storage:
Polymer Clay should be stored in a cool, dry place. The plasticizers in the clay will leach out of the clay with time, so use fresh clay if possible. Various additives are available to help recondition older crumbling clay which has less plasticizer. Avoid storing uncured clay in hard plastic containers or plastic wrap.
Store uncured clay in glass or metal containers which are dedicated for clay use and will not be used for food. Once anything has come in contact with polymer clay, it should no longer be used for food.
Removing Excess Plasticizer:
If your clay is too soft when you open the package, you can leach out excess plasticizer out by rolling the clay into thin sheets and storing it for several days pressed between sheets of white printing paper. Dispose of the paper safely after the clay has been leached in this way.
Control Curing Temperature:
Use an Oven Thermometer
When curing or baking polymer clay use an oven thermometer - don't trust your oven to be accurate. Most ovens are off by between 25-50 degrees.
The thicker the item, the longer it must be baked. Small beads may need only 10- 20 minutes.
Brands and Characteristics - Listed from Firm to Soft:
- Fimo(Classic)remains fairly flexible after baking. Dark colors darken with baking. Fimo is a firm clay and needs conditioning by kneading to reach a workable consistency. Once conditioned. Fimo does not turn sticky with extended handling. Fimo's stiffness makes it good for canes. Like Cernit, Fimo appears to have a moisture absorbing filler. Talc or cornstarch are the preferred mold release agents for these clays.
Puppen Fimo is a special formulation of Fimo designed for doll-makers. It comes in three colors;-porcelain, rose, and natural in 500 gram (1.1lb) packages.
- Cernit is translucent in all colors unless you specifically add an opaque white clay to it. Cernit becomes progressively softer the more it is handled. Cernit has a high elasticity when green which means extremely thin sections can be rolled out without crumbling. The same elasticity means a ball will dimple when a pointed object is pressed into it. In cured pieces Cernit has a very high strength and remains somewhat flexible after baking with a semi matte finish. Like Fimo, Cernit appears to have a moisture absorbing filler. Talc or cornstarch are the preferred mold release agents for these clays.
- Cernit’s modeling characteristics, translucence and strong curing mean it is the favored polymer clay for doll sculptors. Its tendency to soften makes it less popular in warm climates or with people who want strong firm outlines for clay canes. A wide range of flesh tones are available in 500 gm packs for dollmakers.
- Kato Poly Clay has a strong following amongst people who cane. The canes retain their flexibility for a long time and slices can be cut immediately after being caned. Kato is firmer than Premo, but not as firm or crumbly as Fimo Classic. Kato Polyclay doesn't turn sticky with extended periods of handling. It is an ideal choice for detailed canework. Once cured, it is very strong and flexible. Kato polyclay darkens only slightly with baking.
- Premo (Premo Sculpey) is a very strong clay which remains flexible after curing. Premo is available in a range of colors which are designed to mix similar to paints in an artist’s palette. Premo is firmer than the other Sculpey clays but softer than Fimo. It can easily be conditioned by hand. Like other sculpey clays water is the preferred release agent for molds for this clay.
- Sculpey III is brittle in sheets but is fine for beads or other round shapes. It is a very soft clay which is easy to work straight from the package. It may not be suitable for use in warm climates. Sculpey III is not very suitable for canes which may smear when sliced. The color pigments are very strong. This is a very good clay for blending due to it’s smearing tendencies. Water is a preferred release agent if using Sculpey in molds.
- Sculpey is very soft and easily worked but also breaks easily after curing. It comes in white or terra cotta colors.
- Super Sculpey is sold in boxes, with the smallest size being 1 lb. Its only color is a pinkish beige. It is fairly durable when cured.
- Super Sculpey Firm is sold in 1 lb boxes of grey color only.. It is harder than Super Sculpey and was designed for sculptors as a carving clay which retains fine details.