i use fiberglass right now, and i would like to try making a weapon with a graphite core, but i have no idea what size i should start with. i'd start with a longsword, but if it was worth it, i might create a polearm out of it.
Just a heads up - make sure you check with chapters regarding weapon construction before you assume that your weapon will be usable. In Chicago, we are very picky on cores, and require a core sample for ultralights to inspect, before allowing the weapon in.