In the glass making process, a variety of different inputs are used as raw material. Most types of glass are made from a combination of silica sand, soda ash, sodium carbonate, lime, and other minerals, which are melted down into a material with a taffy-like consistency. This raw material is then floated, pulled, and rolled out to a uniform thickness.
Iron is a mineral that often appears in the glass mixture, due in part to the fact that many of the materials and processes used in glass manufacturing naturally carry trace amounts of iron. In many scenarios, it isn’t a problem for glass to contain a small amount of iron — especially in applications where the glass must be very thin, or non-transparent.
The potential problem with iron in glass is that it affects the clarity of the glass, especially as the glass thickness increases. General-purpose, unprocessed float glass is not 100 percent clear — it actually has a greenish-blue tint when seen under light. If you’ve ever seen several panes of clear float glass stacked on top of each other, you’ve probably noticed that the whole stack tends to take on a translucent green hue. This effect is also noticeable if you look at a thick pane of glass from the side.
This greenish or bluish tint is due to the iron content in the raw material that was used to produce the glass. The more iron there is present in the glass mixture, the less transparent the final product will be, especially at higher thicknesses.
Coniston distributes low-iron glass with as little as 10 percent of the normal amount of iron particles present in the manufacturing mix, for panes that are crystal clear even at thicknesses of up to 19mm. This extremely low iron concentration allows you to emphasize the view rather than the glass. For projects where budget is more of a concern, low-iron glass is available in thinner dimensions and with different ratios of iron content that remain low relative to the average float glass composition.
Suppliers of low-iron glass and other glass products offer low-iron glass with low-e coatings, for glass panes that allow the maximum proportion of visible light to pass through while reflecting heat and UV energy. Passive and solar-control low-e coatings are suitable for use with low-iron glass, so you have control over the energy spectrum entering or exiting an indoor space. Low-iron glass can also be worked into other processing applications such as tempered glass and laminated glass, lending itself well to gallery and resort settings where public safety and enjoyment are emphasized.