Casting method with a vacuum bonded dry sand core

A method of casting an object requiring cored inserts:

• a. prepare core box elements having walls for defining a core cavity with an opening at one location,
• b. insert a consumable impermeable thin ply of continuous material onto and throughout said cavity walls in a manner to conform identically to the contours of said cavity walls and form an enclosed shape,
• c. inject ceramic particulate material through said opening into the interior of said impermeable thin ply shape, continue said injection in sufficient quantity to form a material shape which occupies the entire cavity space except for the ply of material separating said cavity walls from said particulate material,
• d. while drawing a vacuum on said continuous material shape sufficient to draw the continuous material intimately about the sand shape, permanently close said continuous material at said opening through which said sand is inserted so that the particulate material will not deviate from the intended outer contour of said core, said assembly forming a tight durable self-supporting wrapped core with the consumable continuous material forming the outer skin thereof,
• e. place said wrapped core shape into a porous molding cavity and introduce molten metal to displace said consumable continuous material and define a casting thereabout, and
• f. subsequent to definition of the casting, disintegrate said particulate material by impact strip from the interior of said casting.