Ingot-mould
The Encyclopedia of Founding (1892)
The metal, sand, or fire-brick moulds in which metals are cast to form ingots suitable for manufacturing and commercial purposes. The brass-founder's ingot-moulds are of cast iron, about two feet long and wide enough to form three tapered ingots 7 by 2 inches, or of a size suitable for stowing in the crucible for remelting. The webs which divide such an ingot-mould into three are notched at the top, midway; this allows of each mould being filled without removing the crucible from that in which the metal is poured. See INGOT; BRASS SCRAPS; BRASS. Insect Casts in Metal.--To produce a perfect cast of an insect, animal, or vegetable in metal, it is only necessary to obtain a box large enough to hold whatever it is desired to produce, with a little space to spare. After suspending the object with strings in a suitable position, attach the vents and pouring-gate, and fill the space with a composition made from plaster of Paris 2 parts, and finely ground brick-dust or talc 1 part. The operation must be carefully performed. The whole is then gently dried, and afterwards made red-hot so as to reduce to fine ashes whatever was placed therein. The vents, being placed at all the extremities, are of assistance in blowing the ashes out at the running-gate, and these in conjunction with the holes made by the strings will permit all gas to escape when the metal is poured in at the gate. A good alloy for small objects cast after this manner is tin 6, lead 3, bismuth 2.
What Has Changed in the Last Century
When the Encyclopedia of Founding described these cast-iron trays in 1892, pouring metal into ingot moulds was simply how metal was made ready for sale and remelting. For steel that is largely over: continuous casting, developed commercially from the 1950s and 1960s, now accounts for the great majority of world steel output, with the molten metal solidifying into strand rather than into individual ingots, and ingot casting surviving mainly for very large forgings and specialty grades. The brass-founder's three-slot ingot mould, though, is still a recognisable piece of foundry equipment, and remelt ingots are still cast to convenient crucible-charge sizes. The entry's second half, burning out an insect inside a plaster-and-brick-dust mould, is the ancestor of modern investment casting, which now uses ceramic shells and wax or 3D-printed patterns to make turbine blades and dental work.
Written for this edition, 2026.