Maybe someone here will have an idea where I can get some information. I am planning on making liquid nitrogen from air and will need to regenerate waste gas. This gas will be very cold (-300F) and will get transported through some tubing system. Is anyone aware of any plastic tubing material that will tolerate these temperatures? Polycarbonate is the best I have found so far, but it is not good enough. Otherwise, I will have to use metal tubing.