Heisey Glass Types - Heisey Glass Museum

Pressed Glass Pressed glassware is made by pressing molten glass into a mold to create the shape and design desired. There are two types:

Hand-pressed glass is completely fabricated by hand operations.

Machine-pressed glass is produced by automatic methods and mechanical equipment.

Both types and, occasionally, blown pieces are frequently finished by direct application of flames to produce a smooth and brilliant surface or to alter the shape. This process is referred to as “fire polishing” or “glazing.” Heisey’s glassware was hand pressed and often was described as “fire polished.”

Blown Glass This type of glassware is shaped by air pressure from the mouth or an air compressor. When a mold is used to make blown-glass items, the pressure of the air forces the molten glass to the shape of the mold. There are several types:

Off-hand blown glass is produced by an expert blowing without the aid of molds. All finishing and polishing is done by highly trained craftsmen.

Hand-blown glass is always mouth-blown and is completely fabricated by hand. Molds are frequently used, and expert workmanship is required. This is the method used by A. H. Heisey & Co.

Machine-blown glass is fed into molds by an automatic feeding device and is shaped by compressed air.

Etched Glass Etchings are produced by using strong acids to “eat” the designs into the glass. Some etched designs are imitated by “sandblasting” or decorating with enamel paint. Plate etching is produced by engraving a design onto a metal plate. The plate is inked, then the ink is transferred to a paper made especially for etching. This paper print is fitted to the article to be etched and the ink is firmly pressed against the glass. When the ink is transferred onto the glass, the paper is removed. Except where the design is to be etched, the glass is covered with beeswax. The glassware is then submerged in acid, which eats the exposed glass. After the wax is washed off in hot water, a silver-gray plate etching results. Needle etching is produced by a machine that activates needles, which trace the desired design through wax or protective film. The film is applied so that part of the glass is exposed. The glass is then placed in contact with acid, which eats the design into the glass. The wax is then removed. Engraving on glassware is done by cutting out a pattern by hand using revolving copper wheels, stone, or other abrasives. The decoration is usually left a gray color.

Cut Glass “Cut glass” refers to a product that has been cut by hand or machine, using metal or abrasive wheels or disks. Only glass that is cut by hand may be described as “hand cut.” The cuttings may then be polished by buffing or immersing the glass in an acid bath to restore a clear, transparent surface. Such cuttings are known as “polished cuttings.” Over a period of years, several manufacturers have used the terms “polished cuttings” and “rock crystal cuttings” synonymously in describing such cut glassware. When so used, the term “rock crystal cutting” only means the the glassware has a highly polished cutting. Cuttings may be left unpolished or gray. Polished cuttings, gray cuttings, and combinations of both are properly described as “cut glass.” Sand carving is a modern process of sandblasting or using other abrasives to create a design through a mask on the surface of the glass. This produces a gray satin finish. Frosted effects are produced on glassware by exposing all or part of the glass surface to acids. Or, they can also be produced by applying adhesive to all or part of the glass surface. Powdered glass grains stick to the adhesives and are later “fired on” permanently. Sometimes a frosted effect is produced by sandblasting or by applying a matte finish by using a brush or spray.

Colored Glass Color is produced not by dyes, but by various mineral salts. Simulated color is sometimes produced by spraying chemical paint, which is then fired.