Technical information & FAQs

1. Materials Used:

All Synthware® laboratory glassware is made of high-quality borosilicate 3.3 tubing purchased from market leaders such as Schott Duran, Simax, and BGIF.


2. General Properties of Laboratory Borosilicate Glass 3.3

The properties of borosilicate glass type 3.3 are specified in the international standard DIN ISO 3585.

Borosilicate glass 3.3 has very good chemical and physical properties. It is used for applications that require not only very good chemical and thermal resistance, but also resistance to thermal shock and high mechanical stability.

The recommended positive continuous operating temperature for Borosilicate glass 3.3 is 350 °C. This temperature may be exceeded for a short period. The glass transition temperature is 525 °C. The melting point is 820 °C.

The recommended negative continuous operating temperature for Borosilicate glass 3.3 is -70 °C. Borosilicate glass 3.3 is also suitable for use with liquid nitrogen. During such freezing, it is merely necessary to take into account the expansion of the content in order to prevent damage to the glass apparatus.

It must be ensured that the temperature difference does not exceed 100 K during cooling and thawing.

Great internal tension is induced in glass that is exposed to high temperature differences, which may lead to glass breakage (crack or shatter)


3. Pressure Vessels

The pressure vessels are made of thick-walled borosilicate glass 3.3 tubes and can be used under normal conditions for applications with pressures of up to 6 bar.

Important warning for pressurized glassware: Due to varying conditions (e.g., corrosive solutions, temperatures, duration), we cannot guarantee that the glass vessels will be able to withstand the pressure.

The pressure vessels should be evacuated or pressurized slowly.

Before each use, a visual inspection of the pressure vessel should be performed to detect any damage, such as scratches and hairline cracks, that will affect stability and may cause consequential damage.

Please observe all safety precautions and always work behind a safety shield.


4. Porosity Grade Table

Abbreviation Description Pore size, µm
XC, X Extra Coarse 80-120
C Coarse 40-80
M Medium 15-40
F Fine 5-15


5. Safety Instructions

Before each use, carry out a visual check. Defective laboratory glassware has to be disposed of properly.

  • When stressing the glass apparatus, the thermal and mechanical properties must be considered. The threshold values must not be exceeded.
  • Scratched glass is more likely to break during an experiment. To avoid damage to the surfaces, the glassware must be stored and used carefully.
  • Sudden pressure changes must be avoided.
  • When sudden changes in temperature are induced, the thermal shock resistance (dT<=100 K) must be taken into account.
  • To avoid breakage while clamping glassware, use suitable equipment and do not use excessive force to tighten clamps, racks, or ring stands.


6. Precision-ground glass stopcocks

Our manifolds come with precision-ground glass stopcocks. These are stopcocks where the housing and the plug are matched to one another. Each stopcock is therefore unique and has a number on both the plug and the housing. Each stopcock is checked individually for perfect tightness. It is extremely difficult to produce a replacement plug without a housing. In addition, the tightness of the stopcock can no longer be guaranteed due to natural wear and tear of the housing used.
If a plug is broken or lost during use, it is strongly recommended that a new complete stopcock be obtained and installed by a glassblower on site. This service cannot be offered by us at present.


7. O-Ring-Organic Solvent Compatibility Chart (Please see notes 1, 2)

Organic Solvents Viton® EP®
Acetic Acid D B
Acetic Anhydride D B
Acetone D A
Ammonia D A
Benzene A D
Benzyl Chloride A D
Bromine A D
Butane A D
Carbon Tetrachloride A D
Chloroform A D
Cyclohexane A D
Decane A D
Diethyl Ether D D
Ethanol C A
Ethyl Acetate D B
Gasoline A D
n-Hexane A D
Isobutyl Alcohol A A
Kerosene A D
Methanol D A
Methyl Ethyl Ketone D A
Pentane A D
Propane A D
Pyridine D B
Toluene C D

A - Excellent. Volumetric swell is less than 10% after exposure.
B - Good. Limited exposure is recommended.
C - Fair. Volumetric swell is between 20% - 40% after exposure. Limited exposure
and frequent O-ring replacements may be necessary.
D - Poor. Not suitable for this type of reaction / condition.
 1.    We cannot be responsible for use of the above data in specific applications. Immersion testing under actual conditions is always recommended.
 2.    Fluorinated products should never be exposed to molten or gaseous alkali metals such as sodium or potassium, since vigorous exothermic reaction may occur.


8. Proper Disposal

Due to its high melting point, borosilicate glass 3.3 should not be disposed of in domestic glass recycling facilities under any circumstances. Considering its contamination, the disposal of such glassware must take place in accordance with the applicable guidelines.