Abstract: Controlling the release from a conical ceramic crucible of molten thermite eaction products (generally, iron and alumina) to effect optimum penetration of metallic targets by said molten products through the use of metallic discs which are completely protected on their sides against the molten products, thus forcing these molten products to melt the discs sequentially from top to bottom, resulting in a delay of flow of the molten products from the conical crucible to thus permit the molten iron, heavier than the molten alumina, to substantially unimpededly transfer its heat to the metallic target, the molten iron being more efficient in melting metallic materials than the molten alumina.