been doing some poking around and found this stuff called Eco foam board/ Eco board. Suppose to be cheaper, lighter and stronger than balsa,
http://www.ecospecifier.co.za/products/public/greentech_eco_board_ecg_premium_cat_2_stock_available
this place has a write up/ spec about it, what you think?
A few places iv found say its a cheaper and lighter replacement to MDF. its rated 1.1g per m3 not sure how accurate that is, since i think balse is generaly 120kg/m3 (from what i can tell anyway) which would make the eco board VERY lightweight in comparison. Maybe a new building material for planes? :D