Dry-sand moulds:

These dry-sand moulds are not very famous, although, because of the long time needed for drying, the added expense of that operation, and the availability of practical alternatives. An attractive compromise is to generate a skin-dried mould, drying just the sand that is adjacent to the mould cavity. Torches are frequently used to carry out the drying, and usually the water is removed to a depth of around one-half inch.

Moulds utilized for the casting of steel are almost always skin-dried, because the pouring temperatures are considerably higher than those for cast iron. These moulds might also be given a high-silica treatment prior to drying to enhance the refractoriness of the surface, or the more-stable zircon sand might be utilized as a facing. Additional binders, such as, lin-seed oil, molasses or corn flour, might be added to the facing sand to provide additional strength to the skin-dried segment.