The procedure is based on the ČSN EN ISO 2811-1 standard – Paint materials – determining the density – Pycnometric method. This standard is a Czech language version of the EN ISO 2411-1:2001 standard. We apply a Gay-Lussac 25 or 50 ml pycnometer.
- Both the sample and the pycnometer to be tempered to the temperature of 20 ± 0,5°C. The pycnometer to be weighed with a maximum possible accuracy using an analytical balance.
- The pycnometr to be filled with a lacquer sample in such a way as to eliminate creation and content of bubbles.
- The pycnometer is carefully sealed so that the ground joint is fully fitting. The lacquer which has outflown from the pycnometer to be thoroughly cleaned with a solvent.
- The pycnometer that contains the tested lacquer to be weighed with a maximum possible accuracy.
The lacquer´s density ρ expressed in grams per mililiter at the test temperature of 20 ± 0,5°C shall be calculated according to the following equation:
ρ = (m2 – m1) / Vt
where: ρ is the density expressed in grams per mililiter
m1 is the weight of empty pycnometer in grams
m2 is the weight of pycnometer with the test sample at 20 ± 0,5°C in grams
Vt is the volume of the pycnometer in mililiters at 20 ± 0,5°C.
The value measured is given with the accurracy of 0,01 grams per mililiter.