nowhere I know of... most guys and I imagine all the local windsurf board shapers hot wire there own blanks out of a big block of EPS (expanded polystyrene) or XPS (extruded polystyrene) foam.
they use this foam for all sorts of packaging and insulation applications.
google or you tube hot wire foam cutting - there is plenty of info out there.
Try surf blanks australia. Or Buford Foam also Australia i am not sure if they still sell them since the closing of clark foam in the US. If its your first attempt don't get a close tolerance blank as you will more than likely get it wrong. You also need some rocker templates which you can make if you are handy with the woodworking tools. Hope this helps.
There a polystyrene supplier in Welshpool not far from Abernathy rd where you can get thne big blocks for hot wiring from, they also do different densities.
