Because plaster is a porous material, special care must be taken in painting it. Plaster molds are available for children's crafts, adult's crafts and even for decorating walls and woodwork. Paint them correctly so your artwork and handiwork will endure.
Visit your local paint supply store or craft supply store and purchase a few items for painting plaster molds. You will need oil based paints in the colors you desire, as well as paintbrushes and clear polyurethane top coat. Molds are available for purchase at most craft supply stores. Decorative molds for walls and trim are available at home and garden supply stores. In addition to your plaster molds
Assemble your supplies and lay your plaster mold onto a tarp or piece of plastic or canvas sheeting to protect your work space. Begin by applying a base coat of paint onto your mold. If you are painting a plaster mold of a person's face, for example, your base coat will likely be a skin color. Allow your base coat to dry for a half hour before applying a second coat. Once you have painted all needed colors onto your plaster mold, allow the mold to dry for about an hour before proceeding.
Once your paint is dry to the touch, it is time to apply a coat of clear polyurethane finish. This gives the plaster mold a glossy, durable finish that will withstand humidity, heat and other climate issues within the home. Polyurethane will also protect it from liquid spills.
Apply the first coat of polyurethane with a paint brush and allow it to dry for about an hour. If you will be displaying or using this piece in a high traffic area or some place where you feel it could sustain damage from water or excessive handling, it's best to apply a second coat. Allow several hours of drying time after applying a second coat of polyurethane.