The tin bath bottom casing is made of steel. It is important that the finished casing is water-/gas-tight and has a minimum amount of welded joints inside which will be exposed to the liquid tin. For this reason, each section of the bottom casing widthwise is a one-piece element. Inner surface of the casing must be smooth with the metallic luster and have a minimum elevation difference. The bottom casing fixed at the beginning of the tin bath is placed on the roller bearings to allow the thermal expansion of the structure.
From inside the bottom casing is completely lined up with the refractory material which will later be in contact with tin. Each bottom block is firmly fixed to the casing with the retaining bolt. As the refractories are exposed to high temperatures and liquid tin, they are made of high performance material.