most of them are made from metal tubes,darth vader and luke's saber.
Obi wan's light saber is made from a pvc tube and stuff that's was lying around in my workplace.
for example the ''grenade'' of Obi wan saber is made by myself.made from a thick walled pvc tube.
the Graflex clamps i made those from tin cans.cut in the right shape and dimensions and carved the lines in with a sharp tool, and folded into the right shape.