GhostBusters Part 1

Do you have ghosts in your building?  You know, those nasty images left on screen mesh after you have removed the emulsion resulting in another step to remove them, before you can re-coat them.  These ghosts are also known as “haze” or just nasty stains.  Before we recommend a stain remover it is important to know something about the type stain.  If you know what causes your stain problem you may be able to eliminate life with ghosts without the use of any extra products or steps.

There are two main causes of stain/haze.  The first type is caused by very aggressive high solvent inks designed for ‘low-surface-energy substrates’ and they are designed to be actively aggressive so that they insure adherence to the substrate, which results in staining of screen mesh.  These require the most aggressive chemicals to remove the ghosting.

The second type is caused by ink trapped in the areas where the individual mesh strands cross each other, also known as ‘knuckles’.   There are several reasons for these ghosts.  One being screen mesh that is not stretched to high tension causing the ‘knuckles’ to slighty move with each flood and squeegee stroke trapping small amounts of inks in the knuckle resulting in a ghost image.  The other primary cause is under exposure of emulsion.  When screens are under-exposed only the properly exposed emulsion remains after exposure and rinsing.  Emulsion that is under-exposed will be on the squeegee side of the screen because it is the emulsion that is farthest from the light source.  When this occurs the action of flood and squeegee strokes will drive ink into the knuckles, even high tension screens.

Most screen printers do not use aggressive solvent based inks so as you can that see many of your ghosts can be eliminated without the need of an extra step and extra haze removers.

Know the cause of your ghost as the fist step in eliminating ghosts.  If you still have problems Easiway makes three different haze removers.  EasiSolv Gold & EasiSolv 415 are the most aggressive while EasiSolv 701 is a fast acting haze remover for lighter stains.

Filed under: Easiway Systems News by easiway