Play dough is a simple, manipulative toy that strengthens the fine muscles of the hands and encourages the imagination. While most are concerned with how to keep their play dough soft and pliable, there are times when you might like to harden play dough for preservation. Homemade ornaments or decorative objects made by young children can be preserved through hardening the play dough to keep its shape and appearance.
Lay the play dough creation on a piece of waxed paper. Allow it to remain on the waxed paper long enough for the play dough to harden enough so it can be transferred to a drying rack.
Lift the hardening play dough creation from the waxed paper. Use two spatulas for a larger piece of work.
Set the play dough on a drying rack and allow it to continue hardening for 24 hours. Remove from the rack and decorate with paint, if desired.
Preheat the oven to 93.3 degrees Celsius.
Place the play dough creations on an ungreased baking tray. Bake them in the oven for 30 minutes. Turn off the oven and leave the baking tray with play dough creations in the oven until cooled.
Transfer the hardened play dough creations from the baking tray to the drying rack. Allow them to sit on the drying rack overnight.
Use tempera paint to decorate your hardened play dough creations. Keep hardened play dough creations away from moisture and humidity to avoid them becoming soft again.