I used Polymer clay,it works just like clay, but you bake it in a normal oven. it hardens like solid plastic, that’s what polymer clay is plastic. its my Im sure the artests among you can build better stuff, but its fantastic
but be warned! you need to learn how to sculpt in polymer, first off you build a tinfoil base structure, because polymer cant be more than half inch thick. you also have to bake it for the correct time & temp 15mins at 130,and you need a pasta maker to produce sheets of clay to cover the tin foil, but if you watch some videos on youtube your on your way