The Blast Furnace is a 3x3x4 brick structure, hollow in the middle, for converting Iron Ingots into Steel Ingots.
The Oven is built out of 34 special bricks made from Nether Brick, Soul Sand, and Magma Cream. If broken down, it takes 36 Nether Bricks, 36 Soul Sand, and 9 Magma Creams to build one Blast Furnace. Blast Furnaces cannot be built adjacent to each other – there must be at least one tile in between Furnaces.
Мультиблок «Blast Furnace» — схема постройки видна в книге в игре.