I want to make a small table top completely out of clear cast resin and I am going to embed wooden legs in it at the time of casting. I made a small prototype using polyester clear resin and that worked fine but now I need to make a much bigger mould, probably 30x40 cm and 6cm deep. Am I best off lining a wooden mould with polypropylene sheet or is there a better way of doing this? 

Like stated above, the exothermal reaction could cause some problems.