Make-a-Mold is the winner, hands down, for keepsake casting. Each kit contains a 7¾" × 5" diameter molding container, one bag of molding powder, one bag of cement powder, and one bag of casting plaster. This casting plaster contains the same tough alginate impression material used by the dental industry. Instructions are also included.
The alginate casting material is completely safe, non-toxic, non-allergenic, and organic. It won't harm skin, so it's perfect for all ages.