Molding Boxes
Molding boxes are used to prepare the sand-molds from various types of sand. The typical process is, the sand is packed in through a vibratory process called ramming, and in this case, periodically screeded level. The surface of the sand may then be stabilized with a sizing compound. The pattern is placed on the sand and another molding box segment is added. Additional sand is rammed over and around the pattern. Finally a cover is placed on the box and it is turned and unlatched, so that the halves of the mold may be parted and the pattern with its sprue and vent patterns removed. Additional sizing may be added, and any defects introduced by the removal of the pattern are corrected.
The box is closed again. This forms a “green” mold which must be dried to receive the hot metal. If the mold is not sufficiently dried a steam explosion can occur that can throw molten metal about. Now the molds are ready to pour liquid molten metal.