Zimmermann Color Glass

Four generations of experience in color glass melting.
To manufacture beautiful brilliant color glass today is still a rare art - tradition and experience lead to our success. We are the masters of color glass melting. To obtain the desired color tone, a rich experience in melting and an exact knowledge of glass composition and its raw materials are prerequisites. Glass is colored to each different tone by metal oxides. All colors of the solar spectrum can be obtained. Zimmermann glass stands for competence in color glass rods, granulates and powder.

The founder - Wilhelm Zimmermann 1869 - 1965		Wilhelm Zimmermann jun. 1898 - 1975		Erwin Zimmermann 1927 - 1991		Peter Zimmermann born 1948

The Zimmermann company was founded 1911 by Wilhelm Zimmermann (1869-1965) in Kukan, a small village in the vicinity of Gablonz a.d. Neiße, in the mountains of Iser, Northern Bohemia. Upon gathering a year's experience in the melting and production of glass rods, the Zimmermann family dared to found its own glass factory. Clients for the colored glass rods were the various glass factory and costume jewelry manufacturers in the mountains of Iser. Thanks to the brilliant colors and high quality products, success was soon granted. In 1929, the younger Wilhelm Zimmermann (1898-1975) was able to found a second factory in Gablonz. The Zimmermann companies developed into a reliable supplier of glass rods for the entire Northern Bohemian glass industry.

		Color glass factory Wilhelm Zimmermann Kukan - 1911
Color glass factory Wilhelm Zimmermann jun. Gablonz - 1929

Production decreased sharply during World War II and eventually ceased in 1946 with expropriation and expulsion of the Zimmermann family. In 1947 the younger Wilhelm Zimmermann, together with his sons Wilhelm and Erwin, emigrated to France to work in the glass factory "Ambert, Puy de Dôme" where he soon became responsible for melting and production of color glass.
In 1950 the Zimmermanns returned to Germany and started a glass factory in Schwäbisch-Gmünd under the name "Wilhelm Zimmermann & Sons", for the production of glass rods, granulates and powder.

Color glass factory - 1950 Wilhelm Zimmermann & Söhne Schwäbisch-Gmünd		v.l.t.r.: E. Zimmermann, 3.E.Zimmermann, 6. Erwin Zimmermann, Wilhelm Zimmermann, Wilhelm Zimmermann jun.

In 1960 Wilhelm's son Erwin (1925-1991) started his own business in Germaringen (East Allgäu) together with his wife Margarete. Due to his experience and the resulting availability of excellent colors, Erwin Zimmermann soon succeeded in the establishment of numerous customers.

Erwin and Margarete Zimmermann		M. Zimmermann Verrerie - Germaringen - 1960

Erwin's son Peter Zimmermann joined the glass factory in 1966, and took over after the death of his father in 1991, being the fourth generation of glassmakers in his family.

Peter Zimmermann performing quality control at a color melting oven

Zimmermann's customers are from glass factories and studios all over the world, purchasing color glass rods, color overlay cups, granulates and powders.

Monika Seibt, born Zimmermann, your partner for consultancy, ordering and purchase

Technical Dates

Zimmermann Color Glass products can be processed with almost all standard crystal and lead crystal glass compositions. The coefficient of expansion is set to 90 ± 2 * 10-6 K-1 and has proved to be reliable in daily practice. Nevertheless, we recommend performing initial expansion testing of our glass products together with the ground glass to be used. Slight variation in the expansion of the underlying glass or the color glass may occur, thus the manufacturing of a rod test probe or a ring test probe (see figure) may be advisable.

	Rod test probe A - Expansion of the overlay color glass is higher than the underlying glass - tensile stress B - Expansion of overlay is equivalent to underlay - no strain C - Expansion of overlay glass is smaller than the underlaying glass - compressive stress
Ring test probe A - cut edges of the ring both lie se close together. There is no strain between overlay and underlying glass. B - Ring "locks in", opens; the overlay has a higher expansion than the underlying glass - tensile stress C - Ring overlaps; the overlay has a smaller expansion than the underlying glass - compressive stress

Reference values of processing

The calculated reference values of Zimmermann Color Glass are given in the upper table. However, these values are to be taken as approximations, since variation may occur due to different composition of color glass, which affects the physical values: Zimmermann glass colors are soft special glasses, which heat quickly and may be processed at low temperatures. Due to the favorable working range, colors stay stable and burnouts are avoided, provided the atmosphere in the oven is set to neutral and the drum temperature is not too high or too oxidizing. Customers should be aware that during processing of the flash glass colors red and yellow, the desired color tones only develop after slow reheating.
The specificed coefficient of thermal expansion of our products is a guideline value. It does not represent guaranteed characteristics and is consequently not part of a guarantee.

Processing guidelines - safety instructions

Color glasses are manufactured with metal oxides. Many glass colors contain lead oxide (PbO), arsenic oxide (As2O3) or antimony oxide (Sb2O3). All these heavy metals are bound as silicates in the color glass and are insoluble in aqueous solutions. However, in the interest of occupational health and safety, a high standard of workplace cleanliness is recommended during the processing of color glass rods and granulates. During the processing of color glass powder, dust production should be prevented by avoiding drafts and excessive ventilation (e.g. electric fans). Smoking and food consumption should be prohibited at the workplace (see also material safety data sheets). Color glasses of high quality and high luminescence almost always contain heavy metal oxides. Zimmermann Color Glass is manufactured under strict consideration of occupational and environmental guidelines. Our glass melting ovens are equipped with the latest filtration devices.

Environmental protection helps to preserve nature´s colors.

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