Damaged water glasses


In the case of old insulating glazing with internal metal foils instead of coatings, damage to the foil is known which leads to the panes becoming blind. The thermal or sun protection coatings in the space between the panes can also corrode under certain circumstances in the event of failure of the edge seal and the ingress of water.

Frame constructions
Corrosion processes in the area of ​​the frame constructions or of glass holders, which lead to forced stresses on the panes and thus to breakage due to the associated volume expansion, are critical. In the case of metals, corrosion can also be triggered by direct contact between noble and non-noble metals. If water runs off and is mixed with corrosion residues, visible stripes form on the glass surface. In addition, certain lubricants with which sealing profiles are used in the frame construction can cause changes to the glass surface.

Glass surface
Glass is very resistant to most chemicals. In the case of alkaline attack, however, glass is very sensitive and the surface is burned. This can happen, for example, with water that runs over fresh concrete surfaces, becomes alkaline, and then hits the glass surface. At pH values> 9 to 10, these chemical burns are quickly visible. Aggressive cleaning agents with alkaline components can also cause chemical burns.

But the ion content in the water can also lead to surface damage - but with significantly lower reaction speeds. This process is also known as leaching. Ionized water molecules (H₃O + and HO-), which attack the glass network near the surface, are responsible for this. The result is a white, haptically and visually “dull” coating on the glass surface, which is both visible and tangible. In addition, with very old panes, e.g. certain colored glass in church windows, weathering processes occur on the glass surface, which considerably reduce the transparency of the panes.

Unfortunately, dirt, especially on glass roofs, can also damage the glass surface. In the case of permanent accumulations of dirt with frequent wet-dry phases, components of the dirt can literally eat themselves in. Finally, improper storage of the glass by stacking it outdoors (water ingress) can lead to a significant change in the glass surface.

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