Glass

Silver

Porcelain

Glass History

Glass’ brilliant luster, smooth touch, and harmonious ring have mesmerized man since the first batch of sand and potash was melted to produce a priceless, glowing product.

Glassware dates back to 2500 B.C. during the Bronze Age. Egyptian glass, which can be traced 3000 years, can be found in museums today and it was the Egyptians who were credited with inventing the blowpipe. Subsequently, Romans blew glass not just for table and decorative use, but for windows and glass tiles for floors.

It was at the beginning of the 13th century that glassware thrived, particularly in Venice. Beautifully-colored Venetian glass became known throughout the world; until then, all glass was opaque or tinted. Venetians also discovered a method to produce cristallo, a transparent, clear product. As with porcelain, the process took many years to disseminate though, and it wasn’t until the early 1600s that French and German glass manufacturing was under way. Germans improved the product by replacing soda ash with potash and lime and called the result Bohemian Glass.

England’s contribution was the addition of lead oxide, which lent sparkle, weight, and ring, acquiring a purity and brilliance like rock crystal’s, hence the name crystal. (Lead crystal must contain at least 24% lead oxide. The more lead, the clearer and more refractive the ware.) Lead oxide has been given a bad rap of late, when it was learned that liquid stored in lead crystal over a period of time may leach. The simple lesson is do not store liquids, particularly orange juice, in crystal over long periods of time.

Glassware was not introduced in the U.S. until the early 19th century, since most people could not afford the “liquid gold”. Besides, pewter and wood proved just fine as drinking ware. But, with the 1825 opening of the Sandwich Glass Factory in Massachusetts, glass tableware became abundant and affordable.

Glass is primarily comprised of sand and potash. Crystal is made by melting a mixture of three parts silica (fine sand) to two parts lead oxide, one part potash, and other ingredients to facilitate melting in tanks. This mixture - or the batch - is given a first - or coarse - melting in temperatures between 1000 and 2000 degrees for about 36 hours. A fine melting then takes place in which most of the gas and air bubbles escape. One melting process can take 12 hours. Electric furnaces have accelerated the process and keeps the melting constant, but the tanks must be fired 24 hours a day.

In hand-made glass, a glassmaker inserts an iron blowpipe into the furnace opening, fittingly called the glory hole, where he pulls a gob of molten metal out on the end of his blowpipe, and shapes the glass by spinning and blowing. This offhand forming will result in a bubble or a gob.

Another technique calls for placing molten glass at the end of the pipe, inserting the gob into a mold, and then blowing the glass to fit the mold. Then, the master-blower receives the pipe from the blower, who has formed the bowl at the end. The masterblower casts a small amount of molten glass on the bowl, and, with stem shears, pulls the stem into the desired form. Another gob of glass is added to form the foot which is formed into a flat disc.

To produce bowls, vases, and other hollow items, a blower produces a large bubble at the end of the pipe which the master takes, and, keeping the glass in motion by rolling the pipe on his bench, shears and cuts with special tools. In yet another method, the blown bowl is set on a steel form with the pipe. Under the form is the molten glass which will produce the stem and foot mechanically. The worker maneuvers the machine which discharges the proper amount of glass into the machine to produce the stem and foot which are attached to the bowl.

The stemware is slowly cooled in a lehr to prevent the glass from cracking. Then the removal of the caps, where the piece was broken off from the pipe, is done via machine, which makes a cut with a diamond blade to neutralize surface tension.

In cut crystal, decoration is either by hand or machine. By hand, a worker marks the glass with a crayoned design to guide the cutter, who works with a rough course grit wheel. Fine cutting then follows, giving a smooth finish, although the cut remains with a matte gray finish. An acid polish will remove the matte finish, yielding the glass’ brilliance.

In the case of machine-cut ware, computer-controlled machines can cut glassware, many at a time. These glasses also have a gray cut which must be polished in an acid bath.

In the case of machine-made molded ware, the cut design is actually incorporated into the mold to produce what looks like a cut pattern. The quality of a cutting is usually felt at the edge; the sharper the edge, the more likely it’s a quality piece. Acid baths smooth some of the edge, but a molded pattern is almost always smooth to the touch.

For other forms of decorated glass, there are options. Hand-applied gold or platinum banding is fired to keep the decoration adhered to the glass. Ceramic decals, silk screened decorations, and transfers must be fired as well. Major advances in machine-made glass have included computer-control furnaces (1970); the use of alloyed molds instead of cast iron (1980); and electronic inspection (1980).

The manufacture of glassware can be expensive because of the heat required to melt the raw materials, and, in the case of hand-made glassware, it’s labor-intensiveness. The more hand-work on a product, the more skill required, and therefore, a more expensive product.

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