Pipe insulation
From AmtWiki
Grey plumbing pipe insulation makes a great courtesy padding foam for javelins and polearms. It comes in varying widths so check the width of your preferred core of choice before you pick some up. Home Depot has it available in the plumbing department for approximately $2 for a 4 to 5 foot long stick.
Torqued pipe insulation is also a great substitute for small pieces of PVC if you want to widen your sword handle.
