We have some historical references which might interest you. Some of these will be available through interlibrary loan at your local library. We loan 2nd copies of books we own for free to other libraries. You can check with your local library to take advantage of this service. Were you interested more in historical sources (more of these!) or technical (nuts and bolts of making moulds?)?
Here are some possibilities:
Macbeth-Evans Glass Company. Fifty years of glass making : 1869-1919. Pittsburgh : Macbeth-Evans Glass Company, c1920. 4 p. l., [11]-94 p. “Molds used in glass making,” pp. 59-67 Location: Stacks / Cage
Call Number: TP853.P4 .M11
Taylor, Gay LeCleire. "Out of the mold": a special exhibition. Museum of American Glass at Wheaton Village. April 7 through October 26, 1990 ; text by Gay LeCleire Taylor. Millville, New Jersey : Wheaton Historical Association, Wheaton Village, 1990. 24 p.
Zembala, Dennis Michael. Machines in the glasshouse : the transformation of work in the glass industry, 1820-1915. By Dennis Michael Zembala. Washington, DC : George Washington University, 1984. v, 400 leaves.
CMG has microfiche only. Vitae. Thesis (Ph. D.)--George Washington University, 1984. Bibliography: leaves [386]-400. Glass making techniques (furnaces, blowing and working, molds) for table glass, bottles, windows. 19th century furnaces: pp. 182-227; Mold-makers and machinists: pp. 228-289'; Cutting and grinding devices: p. 289-307; Bottle and window machinery: p. 307-314. A xerox copy of this is kept in the vertical file: Glass production--United States--19th century.
Scholes, Samuel R. Modern Glass Practice. 7th rev. and enlarged ed., Charles H. Greene, ed. Boston: Cahners Books, 1975. 493 pp., ill.
Shand, Errol B. Glass engineering handbook. George W. McLellan, technical consultant, Errol B. Shand, technical consultant. Marietta, OH : CBLS, 2002. 1 v. Reprint of the 1984 McGraw-Hill ed. Includes bibliographical references and index.
Corning Museum of Glass. Pressed Glass: 1825-1925. Corning: the Museum, 1983.
Lattimore, Colin R. English 19th Century Press-moulded Glass. London: Barrie and Jenkins, 1979.
Lee, Ruth Webb. Early American Pressed Glass. Wellesley Hills, Mass.: Lee Publications, 1960.
Revi, Albert C. American Pressed Glass and Figure Bottles. New York: Thomas Nelson and Sons, 1964.
Welker, John [and] Elizabeth. Pressed Glass in America: Encyclopedia of the First Hundred Years 1825-1925. Limited 1st ed. Ivyland, Pa.: Antique Acres Press, 1985.
Wilson, Kenneth M. American Glass 1760-1930. 2 vols. New York: Hudson Hills Press; Toledo: The Toledo Museum of Art, 1994.
< Stacks: NK5112.W74a; Microforms: F-15115>
Colclough, John. Mould Making. London: A & C Black; Oviedo, FL: Gentle Breeze Publishing, 1999. 128 p. Note: Illustrates how to make and use molds for ceramics of varying complexities, both for industrial and artistic use. Includes chapters on the single drop-out mold, the four-part block mold, and multi-cast molds.
