The 4500 M³/day Multistage Flash (MSF) plant fabrication is nearing completion in Kalpakkam, India. This includes in total the fabrication of brine heater, deaerator, vacuum system consisting of steam jet ejector and condensers, process tanks, pumps, piping system and ten rectangular vessels meant for heat recovery and heat rejection in the MSF desalination process. This paper describes the various stages of fabrication using many efficient, similar and dissimilar metal weld joints.