Velora foam from the Galaxy foam store on Charleston and main is the premo foam for our weapon needs. Walmart blue camp mat is usuable and is cheaper. Both are roughly 1/2 thick closed cell foam but the velora is actually lighter and more springy or resilient and thus won't break down as quicker.
It comes in sheets and Galaxy will cut it in any size strips you desire. 1.25" being the minimum width for sword blades.
Taco told me they also have 4 inch thick slabs of the stuff. Large sheets of Closed cell foam that can be made into coreless shields without the need for more foam to be added, only the grip. Center grips can be made by cutting a hole for the hand, a slot for a pvc handle, and then adding gorilla glue. (slop in the glue, spritz with water and leave to foam up and dry) then a few strips of foam over the tops of the grip. Voila.
Now, looking on bestdagstuff.com (where you can buy great fiberglass cores) they have a reblade kit that consists of only one layer of closed cell foam. I believe it to be EVA foam (which is suppose to be the best foam) Since swords need three layers of foam and the normal layer of foam is 1/2" thick, these reblades must be 1 1/2" to 2" thick. Now, if Galaxy has 4" foam, maybe they have 2" foam or 1 1/2" inch foam that can be cut into strips and used as a single piece to make sword making sooo much easier. Stands to reason. Check out the reblade photo on bestdagstuff.com to see what I'm talking about.
Konradr