Has anyone used Alumimum fiol to cast rock face? I think it works better then the castings I bought. Just crinkel the foil un-crinkel, not too much, shape it to fit the space. Leave the edges longer so you can fold them to make a lip. spray with Pam, pour in the plaster and vola! I used Plaster of Paris, which is very heavy and tends to flaten out the foil.