Strange question, but I'm a home brewer... Can you use an old (stripped down to the tank) water heater as a boiling kettle? My concerns include: 1) Is it safe to cook inside the enamel tank (212 + degrees)? 2) Would using a plasma cutter to cut off the top damage the enamel lining? 3) Would it matter if I use an electric or gas tank? 4) If I use an electric water heater, can I use a propane flame to create a boil?