Glass tools and scissors on a bench
Properties of glass
PropertiesBorosilicate
(Pyrex, Kimax, Duran, Simax)
Quartz
Coefficient of expansion
( x 10-7 cm/cm/°C)
32.58.0
Temperature limits230°C (normal use)
400°C (short-term use only)
1000°C
Softening point821°C1580°C
Refractive index
(at sodium D line)
1.4741.458

How to tell if an unknown glass is borosilicate without leaving the lab

  • Borosilicate glass can be readily identified by its refractive index, 1.474.
  • By immersing the glass in a container of a liquid of similar refractive index, the glass will disappear.
  • Such liquids are:
    • Mineral oil
    • Dry benzene-methanol mixture, 84:16 (v/v) at room temperature
    • Anhydrous glycerol

How to identify if an o-ring is viton

Viton floats in perchloroethylene. If it sinks, it’s not Viton.

Glass filter designations
PorosityMicrons
Fine F4–5.5
Medium M10–15
Coarse C40–60
Extra coarse XC170–220

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