Author Topic: Discharge vs Plastisol Vibrancy (CCI)  (Read 5297 times)

Offline ScreenPrinter123

  • Hero Member
  • *****
  • Posts: 863
Re: Discharge vs Plastisol Vibrancy (CCI)
« Reply #30 on: February 13, 2013, 12:03:42 AM »
That's a bummer w. the screen breakdown.  Print looks good though.

70 or 60/90/60 to prevent the blade contributing to breakdown.  You'll get a deeper bend, creating a sort of ink tunnel that will help drive the wb into the fabric.  Couple of things you can do:
  • Round the squeegee corners.
  • Apply emulsion after exposure to beef up the squeegee edges and the start/stop for the blades.

And of course, full exposures.  In the middle of 800pcs right now and not expecting a breakdown.  Aquasol HV + Murakami hardener MS but any good emulsion suitable for wb will get you there.

I use emulsion to blockout any reg marks, fisheyes, pin holes, etc. so that's reason 1 to post expose but I still think it doesn't hurt to hit your long run screens with 2-3x the original expo time on the squeegee side.  I won't hear an argument that this does nothing.  Back in the early days I would develop sometimes underexposed screens (using sunlight) gently dry and post expose from the squeegee side and it worked with diazo emulsions so it definitely is doing something to those pure photopolymers which are noted for being able to further cross link in post exposure.  Not a substitute for complete exposure though.

Thanks for the great tips:

1.  New Squeegees will be ordered most likely tomorrow and we have two 65/95/65 that we will use for this job though I may have a 70 or two lying around.
2.  Will increase our exposure a good bit since diazos typically have such a wide latitude to achieve decent exposure
3. When you beef up edges and squeege start and stop points do you do it on squeege side?
4. When I post exposed I had print side facing the light source so it would make sense to flip this over so that the squeegee side gets a chance for some direct light.
5. Going to try some Aquasol HV since so many people speak highly of it.  Would CCI's Harden X work with the Aquasol HV?


Offline tonypep

  • Ludicrous Speed Member
  • *******
  • Posts: 5675
Re: Discharge vs Plastisol Vibrancy (CCI)
« Reply #31 on: February 13, 2013, 07:29:05 AM »
By the time the PW article comes out you will all know most of this (BTW it will be a two part, first install covers much of history, sorry) The tape leak is classic failure of underexposure and lack of post exposure possibly combined with improper emulsion/coating technique etc. What makes it more frustrating is that the pigment rarely leaks through; making it difficult to identify the suspect screen.
One of the most commomn errors here is the printer/screenmaker is so scared silly (or misinformed) about leaks that the seemingly obvious solution is to tape the screen silly. The reverse is actually more factual. The emulsion (irregardless of brand/technique) needs to "breathe" or perhaps evaporate ever so slightly. Tape obviously inhibits this; and eventually just a immensly slight bit of activated water will seep through and cause the dreaded tape line; often which is not visible until the garments exit the dryer. We harden screens after 144 pcs. Not usually necesssary but I like insurance especially when it doesn't cost much. More later.