A method of assembling a thermosiphon system includes placing a base of an evaporator and a tube of a condensate line in a brazing fixture such that the base covers an aperture in a bottom of the tube with a bottom surface of the base abutting a precision machined surface of the brazing fixture, and simultaneously brazing the base and the tube while held by the brazing fixture to form a unitary body in a single brazing process, the unitary body including the evaporator and the condensate line.