It started as pep, same as nearly everything else I do. I fiberglassed it filled the inside with expanding insulation foam and bondo'd it to get the shape. The ony special part is the blade which is made of steel. I have a friend who is a machinist and he was able to make it for me. As for casting it, I am not sure how I would go about doing that, it is pretty big, I'll have some pics of it monday for the launch party for sure.