pewter

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Pewter alloy plate, 18th century

Pewter is a collective term for tin alloys , which traditionally consist of 85 to 96 percent tin and the rest of copper and / or lead and are mainly used for cast, but also rolled products ( tinfoil ). Modern hard pewter alloys consist of tin, copper, antimony and / or bismuth .

Tin is a bright metallic material that, depending on its composition, oxidizes darkly over time like silver. It is soft enough that workpieces can be easily machined, and the low melting point of around 232 ° C makes it an ideal material for metal casting. Since the mechanical strength of pure tin is too low for everyday objects, it has to be alloyed.

From the Middle Ages to the 18th and 19th centuries, pewter was a widespread material for eating and drinking vessels , but it was largely supplanted in this function by porcelain, glass and other materials. In addition, because of its toxicity, lead has not been used in pewter alloys for everyday objects for a long time. Since the zinc-lead law of 1887 , pewter dishes in Germany were only allowed to contain small amounts of lead. The limit was later set at 0.5% lead (max. 2% copper, max. 7% antimony). Therefore traces of lead are often found in older pieces. The main use of these alloys today, in addition to special applications, is the manufacture of costume jewelry and pewter tools.

Compositions

Pewter was produced in different compositions (exemplary):

  • 96% tin, 4% copper for cutlery and dishes
  • 92% tin, 4% copper, 4% lead for drinking vessels
  • 85% tin, 15% lead for other uses

English names for pewter alloys are Pewter or Britanniametall

  • Britannia metal : tin 65–97%, antimony 1–24%, copper 1–5%, bismuth 1–5%
  • Pewter : e.g. B. tin 81%, antimony 6%, copper 6%, lead 7%
  • Queens metal : tin 88%, antimony 8%, copper 2%, bismuth 2% (source: Richter)

literature

  • Karl Richter (Ed.): Zinc, tin and lead. A detailed description of the properties of these metals, their alloys with each other and with other metals, as well as their processing in physical and chemical ways. For metal workers and art industrialists . ( Chemical-technical library , volume 109). 3. Edition. A. Hartleben Verlag, Vienna / Leipzig 1927.