Sand casting greater cost. With a completed mold at the appropriate moisture content, the box containing the sand mold is then positioned for filling with molten metal—typically iron, steel, bronze, brass, aluminium, magnesium alloys, or various pot metal alloys, which often include lead, tin, and zinc. After being filled with liquid metal the box is set aside until the metal is sufficiently cool to be strong. The sand is then removed, revealing a rough casting that, in the case of iron or steel, may still be glowing red. In the case of metals that are significantly heavier than the casting sand, such
Tube Alloys to produce a chain reaction in a bomb with the power of thousands of tons of TNT. This led to the formation of the MAUD Committee, which called for an all-out effort to develop nuclear weapons. Wallace Akers, who oversaw the project, chose the deliberately misleading name "Tube Alloys". His Tube Alloys Directorate was part of the Department of Scientific and Industrial Research. The Tube Alloys programme in Britain and Canada was the first nuclear weapons project. Due to the high costs, and the fact that Britain was fighting a war within bombing range of its enemies, Tube Alloys was