A Crayon is 93mm (3.66") long and 9mm (0.35") thick, overall. The outer paper wrapping (construction paper) is about .5mm thick, so the ends of the Crayon are actually thinner than the body. To build this into the rockets, I needed a nosecone with the transitions and a tail section with a thickness reduction. Aug 3, 2017 - Explore Martha Cahill's board "Crayon bulletin boards" on Pinterest. See more ideas about Crayon bulletin boards, Bulletin boards, Classroom themes.