This part of ISO 8130 specifies a method for the de-termination of the density of coating powders using a gas comparison pyknometer. It can be used for all types of coating powder, is simple to carry out, but requires more expensive instrumentation than is of-ten used for density determinations.
The density of coating powders can also be deter-mined using the liquid displacement pyknometer method described in ISO 8130-3. The apparatus is relatively inexpensive, but the liquid displacement pyknometer method is liable to give erroneous re-sults, particularly if the powder swells in contact with the displacement liquid used or the displace-ment liquid does not totally displace the air between the powder particles. The liquid displacement method is much slower in execution, less accurate and is only to be used if it can be shown that the same results will be obtained as for the gas com-parison pyknometer method.