Slug disc

from Wikipedia, the free encyclopedia
Bucker glass in the church window
Slug washers in different colors
Plate washer with lead frame from the 16th century
Butz pane windows in the Angelika Kauffmann Museum in Schwarzenberg (Vorarlberg)
Window with slug panes in the Lemkenhafen Mill Museum

A slug disk , slug disk , umbilical disk , wrongly referred to as ox eye or jokingly also bottle bottom , is a round pane of glass 7-15 cm in diameter. Due to production, it has an elevation in the middle, the lump or navel .

Nature and use

A slug is usually made of green forest glass . With modern glass coloring methods, a wide range of colors can be produced today. It has the already mentioned elevation on both sides in the middle and has raised edges. It first appeared in the 14th century for glazing windows . In the 15th and 16th centuries, the slug panes were assembled to form whole windows using lead frames . Some of them have also been dated and painted. While in the 18th century the slug panes were almost completely rejected for new buildings, they reappeared more and more in the 19th century in the course of the romantic era , but were then partly made of pressed, different-colored relief glass. Nowadays, specially manufactured antique glass , not to be confused with antique glass, is used for repairs in the context of monument preservation .

Rectangular curved disks, so-called bulging disks or cambered disks , e.g. B. in house doors, are sometimes incorrectly referred to as slug glazing.

Invention and manufacture

  • Manual spinning of a pane of glass using the moon glass process

  • The outer edge was cut up, for example for church windows. The middle piece is the butt.

  • The Weibersbrunn glassworks , a company of the Kurmainzische Spiegelmanufaktur founded in 1706 , famous for its moon glass production

Up until the nineteenth century, window glass was manufactured manually using two different methods:

  • By direct shaping by pouring the molten glass onto preheated tables and then rolling it thin. This type of glass is called a rolled glass, which not rolled glass may be confused.
  • By blowing - this is also how the slug disk is made.

In the course of time, three different processing techniques were used in glass blowing:

  1. Slug discs with diameters of up to 15 centimeters have been around since the 12th century. Slug discs are made from a ball blown with a glassmaker's pipe , which is attached to a tack iron and then blown off the pipe . When the glass was softened by the heat, the stapling iron was rolled in hand. Due to the centrifugal force , the glass ball opened into a disk . The process is also known as the moon glass process and came from Normandy . The resulting flat glass is cut off. Moon disks were produced by SCHOTT DESAG AG until the second half of the twentieth century .
  2. In the 13th century, the plate disc method was developed with a diameter of up to 28 centimeters. There are no tool marks on the plate washer and the entire shard is evenly thick. It is produced by blowing an Erlenmeyer-like flask. By blasting off the bottom, you get a plate-shaped piece from which the required glass format can be cut.
  3. Larger formats were ultimately created using the glass cylinder process. Most recently, diameters of up to 90 centimeters and lengths of over 2 meters were possible. After cooling, the glass cylinders were cut open and reshaped to sheet glass by reheating in so-called stretching ovens .
Floatglas Waldglas

Timeline: Development of window glass

useful information

The alleged invention of the slug disk by the French Philipp de Cacqueray in 1330 was exposed as a forgery. Glass made with this method was already being used in Rouen at the end of the 13th century .

When slug panes became popular again in the 19th century (not least in Great Britain, for example, due to the introduction of a glass tax, from which the slug panes were exempt and were therefore often used for the rear windows of the house), critical contemporaries often spoke contemptuously of the slug disc romance . The term Butzenscheiben lyric , which was first used by Paul Heyse in 1884 , was also intended to derogate those poets who began to write antiquated verse narratives, such as Rudolf Baumbach (Zlatorog) and Julius Wolff (Der wilde Jäger; Der Rattenfänger von Hameln) .

literature

  • Heinz Merten: Butzenscheibe , in: Reallexikon zur Deutschen Kunstgeschichte , Vol. 3, 1952, Col. 292–298
  • T. Wieckhorst: Historical window glazing: Lexicon terms from antique glass to glass painting . In: Building fabric . 1994, ISSN  0179-2857 (Butzenscheibe: For the production of Butzenscheibe, which appeared in the 14th century and can still be found today as historical glazing, a spherical hollow glass bubble, hand-blown with a glassmaker's pipe, is first compressed or cut open on one side over the flame and closed Round panes with a diameter of approx. 10 cm are flung flat. After the flanging or reinforcement by the glassmaker, the slugs created in this way are connected by lead bridges (lead rods) and joined to form the window pane, the gussets are filled with appropriate pieces of glass or lead bridges Lead rods have to be restored or renewed by hand. Nowadays the window panes are manufactured as cast slug panes using profile rollers.).
  • Rüdiger Becksmann : The windows of the Freiburg Minster . In: Preservation of monuments in Baden-Württemberg . 1980, ISSN  0342-0027 .
  • I. Seligmann and RW Schmid: Warm glass with bars and slugs for historical buildings . In: Building renovation . 1993, ISSN  0939-4680 (In the meantime, large-format slugs are also offered. The double-sided attachment of lead strips creates the effect of lead glazing.).
  • PaX wood windows, Bad Lausick (ed.): PaXclassic specialist conference. Window in the monument to the "Monument '96". Conference contributions from November 1st and 2nd, 1996 . Lukas publishing house for art u. Intellectual history, Bad Lausick 1999, ISBN 3-931836-38-X , p. 102 .
  • E. Drachenberg, R. Meissner: Better protection for all cathedral windows . In: The restoration of Meißen Cathedral 1990–2002 . 2003, ISBN 3-8167-6214-X .

Web links

Commons : Slug pane windows  - collection of pictures, videos and audio files
Wiktionary: Butzenscheibe  - explanations of meanings, word origins, synonyms, translations

Individual evidence

  1. ^ Butzenscheibe in: Meyers Großes Konversations-Lexikon, Volume 3. Leipzig 1905, p. 666.
  2. ^ Bruno Siegelin, Rainer Trumpf: Repair glasses. PaX Classic GmbH, symposium autumn 2002, chap. 7, p. 63 ff.
  3. ^ Rainer Trumpf: Glass in building. PaX Classic GmbH, symposium autumn 2002, chap. 6, p. 59 ff.
  4. ^ Rainer Trumpf: Glass in building. PaX Classic GmbH, symposium autumn 2002, chap. 6, p. 60
  5. ^ Bruno Siegelin, Rainer Trumpf: Repair glasses. PaX Classic GmbH, symposium autumn 2002, chap. 7, p. 65
  6. ^ Rainer Trumpf: Glass in building. PaX Classic GmbH, symposium autumn 2002, chap. 6, p. 59f.