Soda-Lime Float Glass
Economically priced thin sight glass grade material
Special Properties
- Low-cost flat-glass
- Clear transparency under normal lighting conditions
- Reasonable hardness
- Moderately chemically resistant
Typical Applications
- Sight-glasses
- Simple front glass
- Mechanical glass parts
- Covers for fire alarm buttons
Related glass types
- Selected white Float Glass
(iron-reduced float glass with selected surfaces and flatness) - BOROFLOAT® Borosilicate Glass
(borosilicate glass from SCHOTT)
Soda-lime float glass for sight glass applications
Soda-lime-silica float glass materials with sight glass quality are ideal for all use cases that don't require the highest quality surfaces, flatness, or material purity. The glass consists of about 71% silica. Sodium carbonate ("soda") is added to lower the glass transition temperature, increasing the glass's water solubility. Chemical durability is partially gained back by adding calcium oxide ("lime"), magnesium oxide, and aluminum oxide. The result is a low-cost glass with a lowered melting temperature that can be efficiently processed and is suitable for all commercial uses with moderate requirements.
When looking with the naked eye, the glass has a high-quality appearance, and there are no significant defects or inhomogeneities in the material when looking through it. However, this type of silica glass material does not achieve our iron-reduced selected float glass's excellent surface quality and flatness, and its physical purity is not comparable. For example, a slight grey haze can become visible under intense inspection light with sight glass grade soda-lime glass. However, this effect is not perceived under normal lighting conditions and has almost no impact on the transmission. About 90% of visible light is still transmitted, only 1% less than our selected float glass materials offer.
Our soda-lime sight glass has the ideal properties for less sophisticated parts like glass covers, simple housing windows, sight glasses, or protection glasses. It is a low-cost material used for all non-optical use cases that do not need a particular chemical or heat resistance and do not require withstanding an increased operating temperature.
Due to soda-lime glass materials' properties, we don't recommend using them at a high thermal load or in harsh chemical environments. If you are searching for a glass type with higher purity, excellent chemical and increased heat resistance, please look at our borosilicate glass datasheet.
Specifications
Transmission
- Approx. 90% at 400–700 nm
- View transmittance of soda-lime glass (1 mm tk.)
- View transmittance of soda-lime glass (2 mm tk.)
- View transmittance of soda-lime glass (3 mm tk.)
Standard Thicknesses
Please click on a glass thickness to request a quote.Thickness (mm) |
Tolerance |
 |
|---|---|---|
| 1.0 | ±0.1 | ✔ |
| 2.0 | ±0.2 | ✔ |
| 3.0 | ±0.3 | ✔ |
Refractive Index
- Approx. 1.52
Mechanical Density
- Approx. 2.5 g/cm3
Coefficient of Thermal Expansion
- Approx. 87 × 10-6/K
Typical Glass Composition of Soda-Lime Glass*
- SiO2: 71%
- Na2O + K2O: 14%
- CaO: 8.6%
- MgO: 4.4%
- Al2O3: 1.3%
- Fe2O3: 0.1%
- SO3: 0.3%
*The glass composition can fluctuate from batch to batch. The percentages given are only typical averages and do not add up to exactly 100%. Since soda-lime-silica float glass is not an optics-grade glass, all specifications above are subject to inevitable fluctuations. Therefore, all specifications are only rough approximations.
All data and specifications given are average guide values and are not guaranteed. Moreover, please consider the “Notes on Specifications”.
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Last update: March 19, 2025