Mechanical resistance

When using glass, please avoid thermal stresses (e.g. open flames in the transformation temperature range), thermal shocks and damages on the surface as heavy scratches or cracks. This can lead to breakage of the glass and thus can cause injuries.

Printing colours, graduation

We are using two different graduation colours. There are enamel colours, which are melting with the glass surface at the particular burn-in temperature. This long-lasting burnt-in colour has sufficient resistance for the daily use and has due to the rich contrasts an excellent readability. For extreme applications we are using brown diffusion colour. This colour diffuses through ion exchange into the glass surface and is practically indestructible. The intense brown colouring also assures an excellent readability. The graduation of the glass intruments is done by screen printing. For volumetric instruments stretch-stencils are used, which ensure an especially precise compliance with the calibration points.


Laboratory glassware can be cleaned manually or mechanically. It is to be paid attention that particularly on volumetric instruments (e.g. graduations) and at articles with application-specific printings (e.g. filling marks) the temperature of the rinsing bath is not > 70°C when alkalinedetergents are used. Furthermore the exposure time in the rinsing bath should be kept to a minimum. Alkaline media in connection with temperatures > 50°C and longer exposure time can lead to changes in the volume by glass erosion and destruction of the graduation. Our recommendation for cleaning is to use water > 90°C without chemical additives (hot water cleaning). At glass instruments made of soda lime glass, abrupt changes in temperature are to be avoided.




Laboratory glassware

Our glass instruments are made of borosilicate glass 3.3 according to DIN ISO 3585:1998 with the following chemical properties:

• hydrolytic resistance class 1 (DIN ISO 719)

• acid resistance class 1 (DIN 12116)

• alkaline solution resistance class 2 (DIN ISO 695)

Furthermore borosilicate glass 3.3 has very good physical properties, e.g. very high thermal resistance and thermal shock resistance. The maximum short-time working temperature is 500°C. Therefor all our products made of borosilicate glass 3.3 are universally applicable in laboratory and industry. The coefficient of mean linear thermal expansion α(20°C-300°C) acc. to DIN ISO 7991 = 3.3 * 10-6K-1.

For graduated pipettes and volumetric pipettes as well as for Colorimeter cylinders acc. to Nessler soda lime glass with the following chemical properties is used:

• hydrolytic resistance class HGB3 (DIN ISO 719)

• acid resistance class S1 (DIN 12116)

• alkaline solution resistance class A2 (DIN ISO 695)

The coefficient of mean linear thermal expansion α(20°C-300°C) acc. to DIN ISO 7991 = 9.1 * 10-6K-1.