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A glass glossary of key terms

Glassmaking is a very technical field, so there are a lot of terms you may not have come across before. Let’s have a look at some common definitions that will help you to navigate the world of glass.

Types of glass

  1. Laminated glass Pane consisting of two or more sheets of glass permanently bonded together by one or more sheets of plastic interlayer.
  2.  Laminated safety glass Laminated glass that satisfies the test requirements of the relevant safety glazing material standards.
  3. Ordinary annealed glass Glass cooled gradually during manufacture in an annealing operation, to reduce residual stresses and strains that occur during cooling.
  4.  Toughened/tempered glass Glass that is subjected to special heat or chemical treatment so that both the residual surface compression stress and the edge compression stress is greater than heat-strengthened glass.
  5. Toughened safety glass Pane converted to a safety glass by subjection to a process of prestressing, so that if fractured, the entire piece disintegrates into small, relatively harmless particles.The residual surface compression is a minimum of 69 MPa.
  6. Heat strengthened glass Glass with higher levels of mechanical strength by subjection to a process of prestressing so that if fractured, the glass will break into large pieces, which could be harmful if not laminated. The residual surface compression is a minimum of 35 MPa.
  7. Printed glass A single sheet of glass that has ceramic ink embedded into one surface either digitally, screened, or roll-on.This is then fired into the surface permanently when put through the toughening process.
  8. Heat-absorbing glass Glass for absorbing appreciable portions of radiant energy, especially solar power.
  9. Tinted (toned) and printed glassGlass with a material added to give it a light and/or heat-reducing capability and colour.

Types of glass blemishes

  1. Bow Deviation from straightness or flatness.
  2. Bubble Gas-filled cavity in the glass. If close to the surface, it may appear as an ‘open’ bubble, i.e. a hemisphere at the surface. Bubbles may be spherical or elongated (also called ‘blister’ or ‘seed’).
  3. Chip A small shallow piece of glass that has become detached from the plate edge and attached to the face of the sheet. The word ‘chip’ is also often taken to denote the blemish that is left at the edge after the chip has fallen out.
  4. Corners on/off Nib on or near a corner of a sheet.
  5. Delamination An area in laminated glass where the glass sheet has separated from the laminate in a localised area.
  6. Distortion Undulations in the glass, which cause objects to appear distorted or wavy, when viewed through it.

If you’re looking for some expert guidance for your glass solutions, get in touch with the Glasshape team today.