Ringless casting oval for making investment molds for precision casting

A device for producing an investment mold comprising:

• a casing made of plastic material, having opposite open ends and an oval-cross section, the casing having an inner surface defining a casing volume and a lower inner collar separated from the inner surface by a shoulder, the collar being positioned outwardly of the inner surface with respect with an axis of the casing, the casing being thinner in wall thickness at the collar and thicker in wall thickness at the inner surface of the casing, the casing including a radially outwardly extending oval flange extending outwardly from the upper open end of the casing opposite from the collar;
• a base made of plastic material, the base being oval in plan and including an oval neck with a pair of opposite long walls, the neck having an outer surface extending along the axis of the casing and in frictional engagement with the collar, the base including a cylindrical hub extending along the axis when the base and casing are fictionally engaged with each other, a first floor portion extending radially outwardly from the cylindrical hub, the first floor portion having an outer perimeter, the neck extending downwardly from the outer perimeter of the first floor portion and having a corner between the first floor portion and the neck for closely engaging the shoulder of the casing, the first floor portion of the base, the inner surface of the casing and the close engagement of the shoulder and corner forming a downwardly closed investment solution receiving volume, the base further including a radially extending flange extending outwardly from a lower end of the neck and below the casing when the casing and base are fictionally engaged with each other, and beyond the lower end of the casing, an upper portion of the hub extending above the first floor portion including a second floor portion above the first floor portion and a sprue former retainer adapted to engage and retain a sprue former;
• and
• anti-rotation means between the neck long walls and the collar for stopping relative rotation between the casing and base.