Abstract: A paper sleeve and system for application as an insulated riser in a sand mold used to cast metal articles is disclosed. The sleeve, preferably cylindrical, is formed from a plurality of sheets of paper wrapped around one another with, preferably, a space between the edges of each sheet to provide a plurality of spaces or openings extending through the sleeve. Each sheet is treated with a precise amount of fire retardant. The sleeve for a given time period acts as an insulator keeping metal therein liquid until the metal solidifies in the article forming cavity of the sand mold and thereafter decomposes or reduces itself to a harmless carbon ash. The sleeve can function to both feed liquid metal to the article forming cavity in a sand mold and also to supply additional liquid metal to the article cavity upon solidification of the metal therein to eliminate the need for separate risers as now required in conventional foundry practice.
Abstract: A paper sleeve and system for application as an insulated riser in a sand mold used to cast metal articles is disclosed. The sleeve, preferably cylindrical, is formed from a plurality of sheets of paper wrapped around one another with, preferably, a space between the edges of each sheet to provide a plurality of spaces or openings extending through the sleeve. Each sheet is treated with a precise amount of fire retardant. The sleeve for a given time period acts as an insulator keeping metal therein liquid until the metal solidifies in the article forming cavity of the sand mold and thereafter decomposes or reduces itself to a harmless carbon ash. The sleeve can function to both feed liquid metal to the article forming cavity in a sand mold and also to supply additional liquid metal to the article cavity upon solidification of the metal therein to eliminate the need for separate risers as now required in conventional foundry practice.