deadking

I followed a recipe for pouring some stick baits and I have a really nice aluminum mold so I heated the plastic and began to pour. My question is how long does it take for the plastic to harden.....? I waited and waited and waited what seemed to be an hour and still the plastic is like water.....What did I do wrong? Does it take a few hours for one pour to harden? Would appreciate your help before I pour and waste more plastic...Sure isn't like pouring lead...!