Fineness of Grind Gauge
Model: 501, 502, 504
Brand: Sheen Instruments – UK
The Fineness of Grind Gauge is used for the determination of dispersion.
The test consists of placing a small volume of product on the deep end and drawing it with a straight scraper toward the shallow end. The position on the scale where oversize particles and their tracks appear can be rated for determination of dispersion.
Why Use Grind Gauges?
1./ Grinding is expensive – use the gauge to determine minimum grinding time
2./ Insufficiently ground materials yield untidy films with substandard gloss values.
3./ For comparison of different sources of pigment ground for equal times.
4./ Optimisation of grinding equipment.
- The term ‘Hegman’ is sometimes applied as a generic description to these gauges
and, in spite of National and International specifications recommending the adoption of the micron (μm) scale, arbitrary scales such as Hegman, North, FSPT. etc., are sometimes wanted. Each gauge consists of a block of hardened stainless steel with dimensions of: 175mm x 63mm x 13mm (6.9˝ x 2.5˝ x 0.5˝) with either a single or double channel of 12.5mm (0.49˝) width and supplied with a scraper blade.
- Size Ranges 0-25μm, 0-50μm, 0-100μm. Special sizes made to order.
- Fineness-of-Grind Gauge
Method of Use
Reference should be made to the current editions of British Standards 3900 Part C6, International Standard ISO 1524, ASTM-D 1210 Standard and other National Standards for details of the test method. The term ‘fineness of grind’ is defined as the reading obtained on a gauge under specified conditions of test and the reading indicates the depth of the gauge at which discrete solid particles are readily discernible.
The selected gauge should be clean and dry and placed on a flat surface.
A small sample of the test material is poured into the deep end of the groove, then with the scraper blade held at right angles to the gauge with both hands, it is scraped at a steady rate down the length of the gauge. Sufficient downward pressure should be exerted on the scraper to clean the level surface of the gauge but leaving the channel filled with material. Immediately after draw down determine the fineness-of-grind by viewing the gauge, at right angle to its length, at a suitable to view angle.
Observe the point along the channel where the material first shows a predominantly speckled appearance and note the graduation marks between which the number of particles, in a band 3mm wide across the groove, is in the order of 5 to 10. Report the higher graduation figure as the fineness-ofgrind, disregarding any scattered pecks which may appear above the band where the speckles appearance begins. Clean the gauge immediately after use.
- Ref.501 – Double channel gauge
- Ref.501/25: 0-25μm; 501/50: 0-50μm;
- Ref 501/100: 0-100μm
- Ref.502 – Single channel gauge
- Ref.502/25: 0-25μm; 502/50: 0-50μm;
- Ref 502/100: 0-100μm
- Ref.504 – Wide channel gauge
- Ref.504/25: 0-25μm; 504/50: 0-50μm;
- Ref 504/100: 0-100μm
- Ref.505 – Spare scraper blade for any above.