I just brewed 12 gallons of a delicious porter, so what do I win?
As for making a diy blade, it would cost me many times more then just buying one. For wood you would have to align the grain for maximum strength, and have mad carving or tedious sanding skills. For composite you should be using vacuum bagging and lay your cloth for maximum strength. Just like going for Cataraft shafts trump Carlisles, buying a good blade will trump trying to make your own. Unless you have lots of time on your hand and you want to try to make your own. In that case, just go for it and report back here how it goes.