certifications

Specifications of the glass coming from our production

  • The Vetreria la Piastra S.r.l. produces glass sheets used for the second melting or cold binding and granolithic to be inserted in the typical artistic works.
  • The base compositions are part of the sodium-calcium and boron-silicate typology of glasses presenting in the chemical analysis the typical quantities in oxides that define the fusibility, the workability, the physical properties (expansion coefficient).
  • The produced glass, from an aesthetic point of view, can be subdivided in transparent white ("crystal"), coloured, opal, paste coloured.
  • The raw materials forming the mixtures used for the production of glass, do not contain lead oxides and arsenic is not used as refiner, only in limited amount for specific chromatic requirements on limited and specific production batches.
  • The colorations happen through insertion of typical substances that in the corrected dosage specific for the artistic glass, and selectively absorbing the light, determine the desired chromatic effects.
  • The obtaining of the opalescence is due to the presence of crystalline shape fluorides.
  • The product presents an optimal level of annealing, which might be found both during handling and packing, and through test carried out inside the company by means of polarized light.
  • In this regard, in spite of the absence of meaningful tensions present in the glass, the use of protective means during manufacturing is highly recommended and precisely: gloves in order to avoid cut injuries, suitable glasses to protect against splinters. In the presence of dust, it is obligatory to wear respirators to protect the respiratory tract.
  • The second processing which requires the maximum heating at the temperature of 900°C is required to reach the softening of the glass which maintains a high viscosity. Consequently the possible formation of superficial vapour does not cause from an analytical point of view, the presence of appreciable concentrations of volatile elements.
  • Although it is a highly recyclable material, particularly in the containers sector, the different typology in the chemical composition, requires its disposal in compliance with the current regulations.


Compatibility with the Venetian glass

The sheet produced by the Vetreria la Piastra is a rolled flat glass available in 36 colours, realized according to the expansion coefficient of 104 (resulting from chemical researches), compatible with the Venetian glass, Bacchette and Millefiori.

The compatibility guarantees that, during the melting procedure the two glasses perfectly adhere thus avoiding breaks. At all events the Vetreria La Pistra tests every single product before declaring it as “compatible”.

ISO 9001 certification

certificato