< CORE PINS

CORE PRINTS

Another feature sometimes used by founders to stabilise a core is the CORE PRINT.

Usually used in conjunction with core pins, the core print is formed by cutting a small patch out of the wax pattern to expose a section of the underlying core. The surface of the exposed core is distressed, doing this later allows the outer investment to KEY directly into the core thus creating a secure ‘footprint’. The core print is especially useful for casting large, flat surfaces such as bases and other sheet like designs. The dynamics of an metal charge entering a large surface area can sometimes cause the walls of investment mould to be ‘sucked‘ down to the core, blocking off the flow and creating a mis-run cast. A cut core print helps resist this effect and maintain an even air gap throughout the mould cavity.

Any patch cut from the wax pattern to create a print can be cast separately, then welded back in place during the chasing stage. A lost wax ‘core print’ should not be confused with a sand founders core print, this is a distinct feature that enables the correct location of a removable core within a sand mould (see SAND CASTING).

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INFO: The use of cut core prints for lost wax casting can be traced back to at least C9 AD in W. Africa where the Ife metalsmiths cut lozenge insets into selected designs to help support cores [ref].

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© Robert Moule 2008