This came directly from the Argo brand cornstarch website. They have some wonderful crafts that kids can do with their version of Play Dough. http://www.argostarch.com/playClay.asp
ARGO PLAY CLAY
Makes about 2 pounds
1 cup Argo® or Kingsford's® Corn Starch
1 pound (2 cups) baking soda
1 1/4 cups cold water
1 tablespoon Mazola® Oil
1 tablespoon liquid food color, or1 to 2 teaspoons Rit® Dye
1 to 2 teaspoons paste food color
In medium saucepan stir corn starch and baking soda. Add water and oil all at once and stir until smooth.
Stirring constantly, cook over medium heat until mixture reaches the consistency of SLIGHTLY dry mashed potatoes. (Mixture will come to a boil, then start to thicken, first in lumps and then in a thick mass; it should hold its shape.) If Play Clay is overcooked, crafts may crack.
Turn out onto plate and cover with damp cloth; cool.
When cool enough to handle, turn play clay onto work surface dusted with corn starch; knead until smooth and pliable. If not to be used immediately, store completely cooled clay in tightly closed plastic bag or container.
Shape Play Clay as desired by molding into shapes, balls or ropes with hands. Or roll flat with a rolling pin or press with hands, making pieces of moderate thickness. (Thin items [less than 1/4 inch thick] tend to be fragile; very thick pieces often dry unevenly and may crack.) Press or etch designs into soft Play Clay. Plan to glue small pieces together and heads to bodies rather than press Play Clay shapes together.
Air-dry Play Clay overnight on wire racks, turning occasionally to speed up drying and make objects dry evenly. Oven Drying: Preheat oven to 350ºF, then turn oven off. Place undecorated items on a wire rack on a cookie sheet. Place in oven until oven is cold. Repeat as necessary.
Decorate with water color or acrylic paints, felt tip markers, colored glue, glitter glue, crayons. Let dry completely. Coat decorated items with clear acrylic to seal.
Store un-shaped Play Clay in an airtight container or heavy plastic bag in a cool place up to 2 weeks. Knead stored clay until smooth before using.MICROWAVE METHOD: Stir corn starch and baking soda in 2 ½-quart microwavable bowl. Add water and oil all at once and stir until smooth. Microwave at High (100%) uncovered, 2 minutes; stir. Microwave 3 to 4 minutes longer, stirring after each minute until mixture reaches consistency of SLIGHTLY dry mashed potatoes. Complete as above.