Brush on acrylic crackle medium to add an antique look and stylish flare to wood, metal, paper mache, mirror and picture frames or other hard, clean surfaces. Simply apply an acrylic basecoat and add an even layer of crackle medium. Let dry 30-60 minutes before adding a contrasting acrylic topcoat. Cracks will appear in a few minutes...the thicker the application, the greater the crackling but drying time will vary. Once dry, use a final varnish to protect and highlight the cracks.