These are notes regarding the fabrication of costume armor.
Buy foam floor tiles and use that. It's really cheap.
When marking out a pattern onto foam or whatever material you're using, draw registration marks on the material so that it's easier to glue the pieces together.
Use posterboard or card stock for patterns so you can reuse them often.
Apparently "barge cement" is an industry standard for fabricating things like this.
Apply to both sides very lightly and allow to set just a little bit so it's tacky. Then press together.
If making a concave piece, invert the piece after gluing the seams. This will make the adhesive join tighter.
Use a woodburning tool to make "cuts" and other small details for battle damage in foam armor.