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General => General Discussion and ??? => Topic started by: inkstain on February 18, 2015, 11:15:47 PM
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Hi guys,
Few of my screens have been doing this (pic) lately.
Tried cleaning screen, rinsing screen really good.
Thought maybe everything wasn't washed off.
We let it dry completely then put on emulsion and it's been doing the same thing over and over.
Ugh, frustrating.
Any hints/tips on what it might be?
Maybe the mesh needs to be replaced.
Thanks for your help in advance.
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Same thing in the exact same spots? I would have thought degreaser or Stencil remover dripping from unrinsed frame. So as soon as u coat it you see this?
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Hey Inky, can you run down your whole reclaim and prep procedure step by step?
What do you use, and how do you use it?
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Need a proper procedure to clarify how you do it, to find the problem. It can be solved once familiar to it.
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suggestion...... Reclaim your screens as usual. Next time you coat a screen use a clean towel or paper towel wet with either acetone , lacquer thinner or finger nail polish remover to wipe down 50% of the screen immediately before you coat. It will take only a few seconds for the screen to air dry then coat as usual and see if the solvent cleaned half of the screen reacts differently from the normally reclaimed area. If so you are contaminating from your process somewhere along the line.
The trick here is to be absolutely sure the screen is really clean and remains that way for the time between the solvent clean and coating.
Because the solvent will do its work in just a few seconds you can be pretty sure the solvent cleaned screen is clean & was not exposed to any post cleaning contamination.
If you get better results with this test then you have to review your full reclaim process for the bad actor.
mooseman
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Where are you located. This looks like the emulsion froze. Could be a chemistry residue issue but looks like frozen emulsion to me.
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Do you dry you're screens laying on the side? To me this looks like the tape residue or some contaminated water is running down the screen as it sits to dry.
Murphy37
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Or are some screens drying on a rack above, dripping on the lower screens.
Murphy37
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Hi guys,
Few of my screens have been doing this (pic) lately.
Tried cleaning screen, rinsing screen really good.
Thought maybe everything wasn't washed off.
We let it dry completely then put on emulsion and it's been doing the same thing over and over.
Ugh, frustrating.
Any hints/tips on what it might be?
Maybe the mesh needs to be replaced.
Thanks for your help in advance.
My 2 cents, it looks like you are not maintaining even pressure with your coater against the mesh.
If you are coating with one hand, try switching to 2 hands using some kind of a screen holder to allow you to apply even pressure.
Additionally you have some tape wrinkles and are coating over the tape, if the coater rides up on the wrinkles it will cause the somewhat random thicker coating which I think I see in the darker areas.
This can be a side effect of trying to back off on pressure to enhance the EOM, physics of the emulsion are against you. You must maintain even pressure to achieve a uniform thickness.
Keep us posted.
~Kitson
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I'll had screens look just like that in the pass and here are some of the things I'd check for
Humidity/moist, oil's on the screens after reclaim that you might not see, screen's not really dry as you think they are when applying emulsion, to much emulsion on the screen's. If you can get a brand new screen rinse/dry and emulsion you can eliminate the emulsion being bad quick.
darryl
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I also had some a few weeks ago that looked exactly like that. A week later
the emulsion went completely bad. Being in Florida it didn't freeze (might
tonight though) so your emulsion might be going bad. I use Ulano RLX.
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Looks like drips/streaks of some liquid to me...
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Hey Inky, can you run down your whole reclaim and prep procedure step by step?
What do you use, and how do you use it?
I'll had screens look just like that in the pass and here are some of the things I'd check for
Humidity/moist, oil's on the screens after reclaim that you might not see, screen's not really dry as you think they are when applying emulsion, to much emulsion on the screen's. If you can get a brand new screen rinse/dry and emulsion you can eliminate the emulsion being bad quick.
darryl
Looks like drips/streaks of some liquid to me...
Thanks guys for all your help.
I think we found out the culprit.
Our process is this:
Clean ink off of screen.
Put in dip tank for a a couple minutes
Spray out emulsion.
Rinse
Degrease
Rinse again
I think what was happening as of late was rushing with the screens and not letting the degreaser sit for a minute, not rinsing good enough.
We stack our screens side ways. Looks like before we werent rinsing them good enough and chemical was running down and drying in screen. We tried a new screen and took our time and didn't have the same problem. I think we're back to nice screens again.
Do you guys use the same process as us in reclaiming your screens?
How do you guys dry them? Not sure if there is a better way.
Again thanks for all your help!
We appreciate it greatly!
Inkstain
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Depending on what folks clean with, some don't bother to de-grease at all.
I do, and let it dwell for a few minutes before rinsing. I then either dry in the sun or in my drying cabinet.
Cabinet is safer (cleaner).
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Depending on what folks clean with, some don't bother to de-grease at all.
I do, and let it dwell for a few minutes before rinsing. I then either dry in the sun or in my drying cabinet.
Cabinet is safer (cleaner).
Thanks Frog for the info.
For us I think that was a major thing, let the degreaser sit for a bit and do its deal, then rinse.
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haven't degreased in years, for me, waste of time.
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To me, it looks like moisture or chemical residue. It could also be washout booth blow-back.
I would give your washout booth a good cleaning and add a hose for final rinsing (if you're only using a pressure washer) to prevent blow-back.
And add a dehumidifier to your screen room if it doesn't already have one, to ensure that the screens are truly bone dry before coating.
I'm with Dirk. I haven't degreased in ages. However, if it's only specific screens and not others, you may want to give them a thorough degreasing.
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haven't degreased in years, for me, waste of time.
same here with degreasing, well I take that back I do degrease brand new screens.
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I've seen this (not to that extreme but definitely the same thing happening) a couple hundred times just this year. My guy doesn't rinse the screens good enough and there is chemical residual water dripping down from the short rollers since that is what ends up sitting down in the dirty dip tank and then when it doesn't get rinsed thoroughly it drips down in the screen. When I rinse the screens this doesn't happen at all, but you can show someone how to do it properly but if they don't want to do it, you just got to fire them.
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When rinsing chemicals (like degreaser) we want water at high volume, but low pressure, like a regular hose and a broad nozzle (if any nozzle at all)
The exceptoion I make for this is when I use something like Liquid Renuit, which removes stains, haze, and degreases as well. For that, I like a spray with a little oomph, careful to not get blow-back.