Heh, I managed to get 1000 plus Durasteel ore just by visiting mutated planets constantly. Ironic, considering that it was until recently the limiting factor in my building process. Although I doubt large amounts of any substance will be necessary for building mechs. Most vanilla Starbound recipes require very little to make a single unit. And I wonder whether some of the parts will just be straight-up uncraftable, rather than simply requiring that you find the blueprint.