Helpful glass facts


Glass Properties


(Pyrex, Kimax, Duran, Simax)


Coefficient of expansion
( x 10-7 cm/cm/°C)
32.5 8.0
Temperature limits

230°C (Normal use)
400°C ( short-term use only)

Softening Point 821°C 1580°C

Refractive index
(at sodium D line)

1.474 1.458


How to identify if an unknown glass is borosilicate glass, without leaving the Lab!

  • Boroslicate 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 gycerol


How to identify if an o-ring is viton.

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


Glass Filter Designations

Porosity         Microns
Fine F   4-5.5          
Medium M   10-15
Coarse C 40-60
Extra Coarse XC 170-220


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