Aluminum Cylinders comes in various sizes with various pressure ratings. It has a drawback as aluminum is softer than steel it can be dented and gouged more easily than steel tanks. The bottom of the cylinder is flat. The working prerssure for aluminium cylinder is 3,000 psi. Temperature hotter than 180°f reduce the strength of an aluminium cylinder and causes it to explode when filled. The cylinder need not to be galvanized.