Design

1. What defines the special BRUCK glass quality?

2. How is glass manufactured?

3. What types of glass does BRUCK use for its products?

4. What are the distinctive characteristics of hand-blown glass?

5. Which BRUCK products have a special glass quality?

6. How to properly maintain BRUCK glass?

1. What defines the special BRUCK glass quality?

BRUCK luminaires stand for lighting quality, innovative design, durability and eco-friendliness. In this respect, glass is an important material that often contributes to achieving these positive properties in BRUCK luminaires.

BRUCK luminaires made from glass are glamorous furnishing elements. They add that certain something to the room. Whether dichroic-coated, lacquered, opalised, silver-plated or gold-plated, the surfaces always catch the viewer’s attention thanks to their unique appearance.

BRUCK puts great emphasis on quality. Thus, hand-blown BRUCK glass is subject to a 100% quality control in terms of visual appearance and dimensions. Quality checks as part of the glass production process ensure that improperly shaped glass, glass with too great differences with respect to the wall thickness or glass showing scratches is sorted out. In the case of dichroic-coated glass, glass with too many pinholes (not coated points at the size of a pin tip) as well as glass that does not show a distinctive play of colours is rejected additionally.

Furthermore, BRUCK uses glass that is seamed on the inside and on the outside and that partially has polished edges. These edges provide for a clean finish. Due to the manual manufacturing process a glass showing different glass thicknesses is normal. This might result in luminaires not hanging straight. BRUCK also takes targeted measures to prevent this.

It is warranted that BRUCK customers are able to enjoy an unlimited design experience.

In terms of its practical properties, glass is robust and resistant to high temperatures, environmental influences and UV radiation. This makes glass a very durable material.

BRUCK is involved in sustainable environmental programmes. Here, the company does not only restrict itself to energy-saving illuminants. Across the entire process chain, starting from the idea to the production up to the final completion, delivery and disposal the company is committed to sustainability. This means that BRUCK also observes the environmental standards RoHS (Directive on the restriction of the use of certain hazardous substances in electrical and electronic equipment) and REACH (Registration, Evaluation, Authorisation of Chemicals) during the manufacturing process of glass. Moreover, BRUCK uses eco-friendly acid baths for frosting glass as well as environmentally sound water-based varnishes.

2. How is glass manufactured?

The material glass can be manufactured in two ways. While high-quality products are for the most part manufactured manually, thus hand-blown, mass products are produced by machines.

For the manual production of glass a glassmaker needs fire, molten glass and his breath. This way, the glass is manufactured within the framework of a blowing process. The glassmaker forms the viscous molten glass by blowing the glass into a mould to form the desired glass object. By means of tools such as pliers, shears and dies the final appearance of the luminaire is subsequently determined.

In the case of machine-made glass, so-called „pressed glass“ or „glass tubes“, the molten glass is mechanically pressed into a mould. The glass shows seams where several pieces were fitted together and these seams leave „mould lines“, which make the object identifiable as pressed glass. Moreover, pressed glass may have a less perfect surface and the texture might resemble the skin of an orange. BRUCK makes use of pressed glass whenever a high dimensional accuracy is required for the inner and outer diameter of the object.

Glass tubes are manufactured from different types of glass and with different diameters (starting with only a few millimetres up to several centimetres). In most of the production methods, a long glass tube is drawn from the molten mass that is cut into pieces afterwards. Glass tubes are mostly used in laboratories or for chemical experiments since they are particularly temperature resistant as borax is added here during the production process. The advantages of glass tubes are the high surface quality as well as the high degree of accuracy with regard to the inner and outer diameter.

3. What types of glass does BRUCK use for its products?

Crystal glass

For its products, BRUCK generally uses crystal glass – a top-quality, particularly clear, colourless glass with a distinctive brilliance. It distinguishes itself from glass of a lower quality as it does not have a disturbing green tint.

Opal glass

Opal glass is a glass that appears to be milky-white and that is translucent but not transparent. The opal glass used by BRUCK consists of three layers and is thus also called triplex glass. You start with a layer of crystal glass, then a layer of opalised glass follows. Finally, another layer of crystal glass is added. The first layer effectively transmits the light emitted by the illuminant into the glass body. The middle opal layer then ensures a uniform diffusion of the light and makes it soft and pleasant. Thanks to the multiple glass layers, opal glass shows a high brilliancy and a fascinating impression of depth.

Decorated glass

Many types of glass can be decorated. BRUCK uses glass that is frosted, coated by means of vapour deposition, lacquered or metal leaf coated.

Frosted glass

Frosted glass is produced by means of acid etching or sandblasting. Acid-etched glass is manufactured by means of a sophisticated chemical process in an acid bath. The refined glass thus receives a silky-soft surface. Acid-etched glass is generally frosted on the inside and the outside.

The surface of sandblasted glass is roughened by means of sandblasting. Thereby a slightly rougher surface is created than during the acid etching process. Acid-etched glass can be frosted either on the inside or the outside. Thus, a glossy surface can be created without dispensing with the frosting that ensures a softly diffused light inside the glass. Here, it is always sealed using a clear varnish to ensure that it is protected from the ingress of dirt.

Glass coated by means of vapour deposition

Coated glass is manufactured by applying an extremely thin metal ions or metal oxides coating. For producing dichroic coatings, layers of silicon dioxide or titanium dioxide are applied onto the glass in a vacuum chamber. Up to forty layers with a thickness of a ten-thousandth of a millimetre are applied by means of vapour deposition. The basic material used here is hand-blown crystal glass of the highest quality.

Lacquered glass

Lacquered glass is coated with a glossy or matt lacquer. This lacquer is translucent. To achieve a „saturated“ colouring BRUCK glass is provided with several lacquer coatings. For a „light-tight“ coating BRUCK uses a special, lightproof supplementary varnish.

Metal leaf coated glass

Glass coated with metal leaf is manufactured by hand and involves the application of an extremely thin material, the so-called metal leaf. Finally, this metal leaf is sealed with a clear varnish to provide protection. Thus, it is possible to create, for instance, beautiful golden or silver surfaces.

4. What are the distinctive characteristics of hand-blown glass?

Hand-blown glass is handmade. This means that each glass is unique. Different thicknesses in the glass or small air inclusions do not constitute a defect but rather are a sign of valuable handiwork.

The complex process of vapour deposition on glass presents a substantial challenge for BRUCK. Creating a similar play of colours in dichroic glass or minimising the number of so-called „pinholes“, i.e. not coated holes, is only possible by hand. For this, BRUCK only deploys very conscientious and experienced employees. Should you, despite the strict selection process, once be unsatisfied with the quality of the luminaire do not hesitate to contact the BRUCK customer service via telephone on 02323/591-297 or send an email to vertrieb@bruck.de. We will find a customer-oriented solution for your problem.

Differences in the glass thicknesses

Since the glass is manufactured manually, the thickness of the glass might vary in several places. Under certain circumstances, this may lead to the luminaire hanging crooked. In order to prevent this, BRUCK has taken different measures with regard to the respective products. All glass luminaire heads are provided with a metal rod that stabilises the luminaire body. The outer glass of the Silva range is screwed together with the opalised interior glass. If the outer glass thickness varies around the central opening the interior glass might be hanging crooked. This is especially the case if the interior glass is bolted to the outer glass quite firmly. This can be remedied by slightly loosening the bolted connection, Moreover, the interior glass can be gradually twisted to finely align the inner glass. Glass of the Queeny family is specially milled to provide for an accurate fitting of the luminaire head

Inclusions in the glass

Silica sand is the main component of glass and makes up 99%. It is a natural raw material that mainly consists of silica grains. Silica sand always has organic inclusions. Due to the high temperatures these are outgassed during the manufacturing process and thus might create small bubble-like air inclusions in the glass. Furthermore, air inclusions may develop while the glassblower blows puffs of air into the molten portion of glass by means of a blowpipe. During this process, oxygen is introduced into the glass which partially remains there.

Different play of colours in applying dichroic coatings

Dichroic coatings involve the application of extremely thin layers with a thickness of a ten-thousandth of a millimetre. Even extremely small deviations of this layer thickness may produce a different play of colours. Therefore glasses with a similar play of colours can only be selected by hand. BRUCK offers its customers a cost-free selection service for the compilation of dichroic glass with a similar play of colours.

Pinholes in coated glass

When providing glass with a coating so-called pinholes may be developed having the size of a pin tip. These points that were not coated cannot be avoided due to the sensitive production process. Glass that has lots of pinholes is sorted out by BRUCK.

5. Which BRUCK products have a special glass quality?

Cantara glass gold

• A hand-blown crystal cylinder provides for a uniform and smooth distribution of light on the inside
• Seamed and polished edges with clear end profiles without any thickening
• Patented glass mounting fixture that cannot be seen from the outside
• Light-proof interior side of the glass that is lacquered in black or white and that is coated with a golden or a silver metal foil in order to suffuse the room with sensuously white or brilliantly cool light
• Coated with protective varnish

Silva Dicro

• Hand-blown crystal glass of the highest grade and with minimum tolerances
• Seamed and polished edges with clear end profiles without any thickening
• Residues (grease etc.) on the glass are removed through several washing and drying processes before applying the dichroic coating
• Application of up to 40 dichroic metal oxide layers to achieve the unique dichroic effect
• Glass reflector glass on the inside ensures a uniform and soft distribution of light

6. How to properly maintain BRUCK glass?

Frosted glass, dichroic-coated glass, lacquered glass, crystal glass

Frosted glass, dichroic-coated glass, lacquered glass as well as crystal glass may be gently cleaned using a damp, soft and lint-free cloth. Please do not use any hard or scratching objects for cleaning. Cleaning the glass in the dishwasher is not recommended.

Metal leaf coated glass

Glass coated with silver leaf or gold leaf may be gently cleaned using a damp, soft and lint-free cloth. Please do not use any hard or scratching objects for cleaning. Cleaning the glass in the dishwasher is not recommended.