Fineness of Grind Determination


BS 3900-C6: ISO 1524 : EN 21524

 Hegman Gauge

Scope and Field of Application

BS 3900-C6, ISO 1524 and EN 21524 are alternative names for the same method which is intended for the determination of the fineness of grind of pigments in liquid paints, inks and related products using a suitable gauge. It is a simple and convenient method of monitoring the progress of the dispersion stage of manufacture and for a QC check on the finished product.

There are no pass/fail criteria defined in the standard. This is a matter of agreement between the parties concerned.

The actual standard is a copyright-protected document and we are not able to provide you with a copy. If required however, you can easily obtain a copy from the British Standards Institution.

 

Summary of Method

We use a Hegman gauge which consists of a steel block into which is machined a groove which is uniformly tapered along its length from 100 microns at one end to zero at the other (25 and 50 micron gauges are also available). A scale denotes the depth of the groove at any point along its length. A portion of the sample is placed in the groove at the deep end and a blade used to draw the liquid down the length of the groove.

When the gauge is viewed at an angle, it is possible to note the point along the length of the groove where it becomes shallow enough for the pigment particles to protrude above the level of the liquid. The pigment particle size at this point can be read from the scale.

Sample Requirements

We require no more than 100 g of sample.

 

Accreditation

PRA is accredited to ISO 17025 by the United Kingdom Accreditation Service (UKAS) to carry out this test.

 

Please contact Peter Collins for further details.

 

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