Pinhole Problems!

[TripleStampPress]

We have recently noticed pinholes in our screens. Not entirely sure how long it has been going on, because they are so incredibly small. We haven't actually had any ink going through them, but they are EVERYWHERE.

They show up after drying, but before exposure, so it is not a film or exposure issue. We dry our screens horizontally, print side down, in a cabinet with a dehumidifier and filtered airflow. We have tried two different emulsions and different scoopcoaters.

We are in Richmond, VA and it is very humid here. Could this be the problem?

We usually coat 1and1 or 1and2 because we print a lot of detailed work.

Any suggestions?

[squeegeethree]

Grease can cause this are you eating potato chips while coating your screens?

[TripleStampPress]

No, but we do use hippie haze remover and degreaser. Still, I think this is a more recent problem.

[squeegeethree]

Try shutting off the airflow and just using the dehumidifier.

[TripleStampPress]

Thanks. I will. What is the theory behind that?

[lil_tuffy]

dust in your screen or emulsion.

[TripleStampPress]

Yeah. That is what I am assuming. Just not sure how it is getting there, or what I can do to stop it. I keep things clean. Maybe the airflow is kicking things around. Like I said, the pinholes are very, very small. It really isn't effecting anything now, I just worry that it will get worse.

[Andymac]

I had an interesting thing happen at a shop last week. Might have some bearing on this or the problem of spots and flaws on newly coated screens. Brand new setup, but they bought a bunch of old equipment, including a washout booth.

So, we run through the usual, they did notice on some brand new screens (which had been degreased before coating) that they had a random smattering of spots and thin bits. ON close inspection, I could see there were bits in the screen on some of the fisheyes, but they had used a pressure washer and were trying to be meticulous. it was no biggie, we exposed screens and touched up, everything worked. I give them the lecture about dust. oversplash from other screens during washout, etc

So, we go through reclaim, stencil comes off, we use the degrease, pressure was etc, looks super clean, then I take my glasses off and give it the closeup hairy eyeball after noticing one spot....there are more. I use the pressure washer, now there are more...

the washout booth looked paintsplattered/typical. I ran my finger along the back joint, and this layer that looked like dirty caulking turns out to be 20 years of crud, and when I touch it, off comes a pile of loose grit. Washing the screen was splashing this crap up, and the pressure washer was really doing it.

maybe have a look at your washout and give it a cleanup from time to time. the last act in reclaim is supposed to get the screen completely clean, not cover it in a fine coating of crud just before coating.

[TripleStampPress]

Andy. It sounds like you are saying that using a big 65 year old concrete utility sink that may or may not be crumbling in some spots and has dirt on it as old as my parents is not the best way to go? I think you could be right. Been meaning to replace it but it has been here that long, and we are not look forward to lifting it out.

[squeegeethree]

Line it with fiberglass.