Feeder insert in casting mould - defines surrounding cavity which becomes filled with melt during pouring

摘要

The insert may be made of solid-resin-asbestos or of asbestos board. Around its outside, and its top, if it is closed at the top, is a layer of destructible matl. e.g. foamed plastics or corrugated cardboard. Apertures lead from the insert inside through the walls to supply melt outwardly, and during pouring the layer is destroyed by the melt contacting it. In a modification a double wall insert is set forth, the melt entering a cavity between the walls during pouring. A destructible layer on the outer surface forms an air-gap in the mould upon removal.