Both Model Magic and Air-Dry Clay can be sealed once your piece is completely dry. Both products generally take 24 hours to dry to the touch; 72 hours to dry completely. When completely dry, you can apply an acrylic varnish or Model Magic Glossy Glaze. If using an acrylic varnish, we recommend testing its compatibility before applying it to a finished piece. Sealing your work will not waterproof it. Exposing the finished piece to water and outdoor elements will have a negative effect on the clay, so we recommend displaying your sculpture indoors.
More information about Model Magic is available online at http://www.crayola.com/things-to-do/how-to-landing/model-magic.aspx.
Air-Dry Clay information can be found at http://www.crayola.com/things-to-do/how-to-landing/airdry-clay.aspx .