Well, you could hinge it....but if you are building w/ foam, not necessary. Just build it to you specific body frame and then put a slice on the inner part of the piece. You can then slip it on and use a buckle, clasp or magnet to hold it closed. Any of these methods would work depending on what type of material you are using and what style armor you are building. Remember, you are building this for you and your body. The templates are generic, and as such, can be sized larger or smaller. There is no reason you have to keep them at the default width size. Adjusting to your body is part of the building process. Build by you, for you, to fit you. Good luck and happy building.