You can easily create a cast in your mold with fondant or gum paste! This can be done by using the "push mold" technique. This works with fondant, gum paste, modeling chocolate, marzipan, and other edible sugar treats.
Once your ComposiMold has cooled back to original rubbery consistency, remove your original part and simply press the fondant or gum paste into the mold. You can also use a "2 part mold" technique and press a ball of fondant in between the two portions of your mold. Coloring can be added to the fondant before or after you make your cast.
Be careful not to warp the fondant casting when removing it from your mold. You can "bend" the mold away from the cast and let the cast "fall" out of the mold.
Cooling the fondant or gum paste will make it firmer so it will not deform as easily when you remove it from the mold