Gasses used for MIG TIG etc are inert. Gas welding has it's uses but for body/chassis work the good old MIG takes some beating, less heat distortion, far less fire risk and in the long run a damn sight cheaper.
Here at LandyZone we have plenty of very knowledgable members so if you have any questions about your Land Rover or just want to connect with other Landy owners, you're in the right place.