Directions Prepare plaster of paris according to directions. When ready, pour a small amount into the greased pie dish. Lightly grease your child’s hand and then press it gently into the center of the dish. Hold it there until the plaster sets—just a couple of minutes. Remove hand and let plaster set completely. A nail can be inserted while the plaster is still moist so the handprint can be hung on a wall. Also, try adding food color to the plaster mix at the start. Similar plaques can be made from footprints, elbows, and knees. Plaster of paris heats up as it mixes, so this step requires close adult supervision. Once the mold has cooled, try pressing play dough or molding clay into it to produce a replica of your child’s hand.