Watch Adam's video and READ FORUMS or you might find yourself banned.
Find the answer, then if there is no answer pm someone that would know from reading of forums. Stop posting all you questions as in topics ya know?
each molding and material is different and so is each model, you might just have to experiment.
You could try my idea and spend 30 dollars, melt down hot glue sticks, and mold the helmet that way, then from the next step your on your own. Unless you want to plaster mold the helmet for 15 bucks, then hot glue the inside and have a hot glue helmet....