Just thought I'd throw this out there for a suggestion, when it comes to making scratch built costumes and you want to go the cardboard route, check your local craft stores for mat boards. (Stuff that you frame artwork with) It comes in large sheets about the size of a decent tabletop and you can cut or score it with razors very easily. Way more 'clean' when it comes to edges, it's thinner than box-style cardboard and it's going to hold up far better than thick paper. The non-colored mat board is cheaper than the rest, but it's obvioulsy not cheap as a box laying around the house. Hope this helps.