October '19

For the Business of Apparel Decorating

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2 0 1 9 O C T O B E R P R I N T W E A R 3 9 We have been trying to eliminate pinholes in our screens for some time now. We have moved to a non- diazo emulsion to prevent pinholes from bubbles, replaced the glass on our exposure unit, and recently phased out film in favor of direct- to-screen. Still, we have pinholes. What can we do? Having covered all those bases, I would bet that you have a cement or bare floor in your screen room. Consider carpeting your screen room. When you open or close the door or curtain to your screen room you are likely stirring up dust from the room and floor that can settle on your screens when the emulsion is wet. This might be happen- ing if you experience pinholes that were not there at the beginning of the run and you could not see during screen taping. This type of pinhole can be caused by a bubble in the emulsion that later wears through during printing. Dust is usually cotton or dirt which are both negatively charged. Carpet is polyester from becoming stirred up again. Addition- ally, don't forget that if you feel that you must use a fan to dry your screens quicker instead of low heat, make sure you are "pull- ing" air from the screen rack. Do not blow air and dust particles onto your wet screens. JOHN MAGEE, POLYONE SPECIALTY INKS which is positively charged. By carpeting your screen room, you provide a dust mag- net. Now, when the door from the screen room swings open or shut, or when your production floor is being swept outside your screen room, you have the carpet to prevent the dust inside your screen room

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