Andrew and Louis had finished a paint job at an apartment complex just outside of Dallas in Rockwall, Texas. When the paint had dried in each of the units, the duo returned to inspect their work before telling the client they were finished. With any luck, a job well done would lead to more work from this property owner.

Both painters used dry film gages to spot check the thickness of the coating.  After a thorough review of the work, they walked to the property manager’s office to inform her that the painting was done.  As they walked, Andrew told Louis, “I think it looks great. And that additive we used should help the paint hold up really well for a few years.” They had used a BYK additive that promised increased scratch resistance and an easier-to-clean paint surface, and while that would lead to a better result for the client, Louis was glad he’d had his Hegman Gage handy before starting the job.

A basic Hegman Gage.
Image courtesy of DIY Trade.

A Hegman Gage is the most commonly used grind gage in professional painting. A grind gage (also known as a “fineness of grind gauge“) measures particles within paint to make sure they have been sufficiently reduced in size, so as to not effect the paint’s gloss, color, smoothness, or uniformity in application. A grind gage is used before the job begins so that you, the professional painter, can be confident that all the additives in your paint have been properly milled and mixed.

A Hegman Gage is a steel block with a set of parallel grooves etched into it. Each groove is of smaller dimension than the one preceding it. Paint is applied to the side of the gage with the deepest grooves and smoothed across the block until it covers the smallest grooves. If the particles within the paint are smaller than the dimensions of the groove, the paint will completely fill it. If the particles are larger than the dimensions of the groove, the paint will not.  Measurements are given in micrometers in most cases.

Different paints and different jobs require different millings of additives. In some cases, the additive used can not be further reduced in size.  In some cases, the quality of the paint will be compromised or the additive will not perform as expected if the particles are not further milled.  A Hegman Gage measures the size of these particles. However, these measurements are worthless if you do not know the specifications of the additives and the requirements of your particular job.

A Drawdown machine combined with a Hegman Gage.
Image courtesy of Gardco.

When you open the lid to your next can of paint, give some consideration to all the chemicals and materials that went in to making the mixture perfect. Using a Hegman gage or another grind gage will help confirm that all additives and particles have been properly milled in the paint so you can proceed with the job.  Click here to learn more about BYK’s exceptional line of grind gages!