Use the following tips to control the variables most commonly encountered in garment screen printing.
Shortcuts taken to rush a screen to press lead to improperly dried screens being exposed, creating a whole host of problems on press including pinholes, stencil breakdown, poor edge definition, and reclaiming difficulty. Consequently, the so-called shortcut becomes a costly, long delay. Consider the following tips for optimizing screen-drying conditions.
Increase air temperature with a heater. Evenness of the heat is also important. The heater must be directed properly inside the cabinet or drying space to minimize hot spots and wide temperature swings. Do not exceed temperatures of 105°F (40°C) as higher temperatures can pre-harden unexposed stencils.
Install a dehumidifier in the drying area. At a relative humidity of 100%, the air can hold no more water. Once the maximum drying temperature is reached, the only way to reduce relative humidity is with a dehumidifier. This should be standard equipment in every screen room.
Create an air exchange system for effective airflow. Moving the air around with a fan is not as effective as exhausting the wet air and providing an intake of new air into the dryer. Blowing the same humid air around will do little to improve drying times. Creating the proper airflow conditions can be much more effective than just increasing temperature or reducing humidity to dry the screens. Don’t use a dirt-caked fan directed at the screen to create airflow. In this case, instead of airflow, you create a dirt blower that will create pinholes in great quantities. Installing air filters over all air exchanges can help keep the dust down (furnace filters work well).
A screen vacuum can help speed the screen-drying process along considerably. They can easily be assembled by purchasing a wet/dry shop vacuum and adding a specialized aluminum screen vacuum nozzle in place of the regular vacuum nozzle (Figure 3). These screen nozzles are available from screen making suppliers and are designed to eliminate damage to stencils and mesh. Vacuuming off excess water on degreased mesh and exposed stencils makes for faster dry times. Note that stencils must be exposed properly and the screen nozzle must be kept clean and free of dings and burrs.
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