Image: Lopes

Tips and Tricks for Mixing Plastisol Inks

Joe Clarke has spent the past 47 years in the lab and in the engineering department, in pre-press and on-press, as an R&D / technical researcher and as a manager of screen print production. Clarke has held executive positions as President of M&R Printing Equipment and as Vice-President at Wilflex [Poly One]. He has been granted a growing number of print-related patents, including one for High-Shear printing with Smilin'Jack - he is a member of the ASDPT, is an Associate Editor for NBM and an SGIA Fellow.

Clarke has presented hundreds of technical papers, written a couple books and published over 600 technical / management articles for which he has been awarded five Swormstedts; the international standard for excellence in technical writing.

Currently Joe Clarke is the President of CPR, a Chicago-based corporation which manufactures Synergy Inks including NexGen; environmentally & financially responsible T-Shirt inks. For more information on CPR, visit

Ever wonder why we need to “warm the ink up” or “wet the mesh out,” either with a robust mixing or by printing some ill-defined number of shirts before we can run production with plastisol inks? The answer is due to the Perennial Plastisol Paradigm (PPP), in which the ink may be thick or thin but it is tacky, and exhibits excessive internal cohesion under applied shearing force to create a STICKY hand.

This traditional tack level is difficult to overcome. It is what 1) causes the need to “stir first” or waste a bunch of tubes 2) forces us to use a ton of pressure and run slowly, and 3) puts most of the flaws in the surface appearance and prohibits image registration.

Fortunately, there are now plastisol inks that are low tack without being runny and don't turn into plasti-bricks. As a rule, this grade of ink is typically shear-thinning so it clears the screen easily and mattes-down to a smooth, imprintable, high opacity surface.