White chocolate is super easy to make and a dream to work with. Here is the link to Shawna McGreevy’s modeling chocolate, which is very detailed and easy to follow: http://mcgreevycakes.com/modeling-chocolate/
Modeling chocolate can be rolled out and used to cover a cake and would be perfect for your hard hat. It is easy (but a little time consuming) to get a perfect finish on modeling chocolate just by using your hands and/or a heated spatula. I used modeling chocolate to cover this helmet. It was one of my first cakes, so it certainly is not perfect. 
Sugar Sugar by SSmiley
