I made a shirt freshman year of high school for a Halloween costume, and here's how. I measured how big around my chest was, then made a strip the length of my circumference and 4 tabs tall. I pinned it down and continued adding rows until it was the length of my torso, then added tabs in a way that would go around my neck and connect together over my shoulders. I did the same for my arms (measuring circumference, etc.), but removed a tab every once in a while going down so that it would be more form fitting (since my shoulders/biceps are larger than my wrists). I then connected* the shoulder part of the arm pieces to the holes left by the shoulder part of the shirt. Finally I wore a gray shirt underneath to compliment the metal and protect my skin. Eventually I hand-sewed the edges of the cotton shirt to the tabs to keep everything from moving around too much. Everyone loved my costume, and years later I still have it, although I eventually took the sleeves off because I had little flexibility with them attached.

*connected using more tabs, not wire or any other means