I wonder if this has happened to anyone else, or if there is already a thread on this problem. I'm still a beginner at screen printing and its ironic then just when you think you've got a handle on all the variables annother one always comes into your path. Anyway enough of that.
What happened this last time I made a screen is that during washout of my exposed stencil, some areas started to become bubbly, wrinkly and peal. I soon noticed that this was in fact, only in the areas where I had previously printed with this screen. What I'm saying is that the last design I printed before reclaiming this screen was causing some kind of problem with my emulsion this time.
I believed that I had cleaned the screen well before reusing. The ink did stain the fabric of the screen, but holding it up to light showed that the mesh was not clogged and the ink was cleared.
I can see from what happened that some how, maybe a chemical reaction occurred but is it also probable that since the ink stain or "haze" was BLACK that it some how affected exposure time/stencil hardness?
I would like to know if anyone else was surprised when this happened to them and if they found a good solution for getting around the problem. I'm not into exposure to caustic chemicals so I'd like to avoid it if possible. For example, I am aware that dish soap makes a good degreaser substitute with a new screen. Anyone have a good non-hazardous or "common household" haze remover idea?
It sounds like you are not exposing for long enough. But if you are concerned it might be your chemicals try CCI chemicals. We have used them for years and love them. We use Citra-Paste for ink degradent, ER-80 for emulsion removal, SC Ink Wash for haze remover and Neutralizer for the degreaser. you do need to degrease everytime you reclaim your screen.
I won't use anything other than citra paste either, I use Ulano QTX or an equivalent and found most other degradents will affect the properties of these types of emulsions turning them into what i call a snot-like consistency. CCI also makes a liquid reclaimer that acts as a degreaser, I haven't degresaed in years and have no problems...
1. For example, I am aware that dish soap makes a good degreaser substitute with a new screen.
2. Anyone have a good non-hazardous or "common household" haze remover idea?
1. Dish soap. Smell that nice clean lemony/pine/citrus smell. That's from a lemon/pine/citrus OIL. I am not aware that dish soap makes a good degreaser soap if you compare it to industrial products. The real test is whether or not water sheets as you pour it down the mesh.
Since you are having problems, you should try and compare an industrial screen printing degreaser so you can determine if your dish soap does as good a job.
2. If you have plastisol stains (vinyl), start with a strong vinyl cleaner before you reclaim. Ulano's All Purpose Ink Wash or CCI's WB-1 or Lawson ID-360 Ink Degradent & Stain Remover
There are also modern stain/haze removers that you can leave on mesh as long as you like AND it doesn't have a UPS hazard fee like traditional caustic haze removers. Lawson HR-2020 or Ulano Walk Away haze removers.
If you can tell that you are having exposure difficulties where there are ink stains, it is clear you need a stain remover.
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How are you measuring? retired Ulano Technical Support Screen printing since 1979 - SGIA Academy Member
i am having the same problem. the only place i get stains are on my registration marks and center lines. anyone know why i get them mainly there? (the areas i tape off after registration)
i am having the same problem. the only place i get stains are on my registration marks and center lines. anyone know why i get them mainly there? (the areas i tape off after registration)
If you have plastisol stains (vinyl), start with a strong water-based vinyl ink wash before or after you remover the stencil. Ulano's All Purpose Ink Wash or CCI's WB-1 or Lawson ID-360 Ink Degradent & Stain Remover.
There are also modern stain/haze removers that you can leave on mesh as long as you like AND it they don't have a UPS hazard fee like traditional caustic haze removers. Lawson HR-2020 or Ulano Walk Away haze removers.
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How are you measuring? retired Ulano Technical Support Screen printing since 1979 - SGIA Academy Member
i am having the same problem. the only place i get stains are on my registration marks and center lines. anyone know why i get them mainly there? (the areas i tape off after registration)
The tape is causing the ink to crosslink - essentially "curing" it in the screen.
Use a good ink removal solvent and a pressure washer and you should be able to get most of it. then Haze remove when necessary
i use blue painters tape to cove my reg marks. ive heard of other people using it as well. maybe i should use the white tape that they sell at ryonet for my reg marks?
i am using ulano qtx emulsion and I have run into a similiar problem with my screens. I have considered that my screens may be underexposed but at the same time they have been fairly dificult to blow out. I have to take them outside in the sun if i burn during the day. I am wondering if the qtx exposes so quickly that it is being effected by the sun on the walk over to the spray out booth.
I am wondering if the qtx exposes so quickly that it is being effected by the sun on the walk over to the spray out booth.
Yes. Coat a small test area with QTX, don't waste a whole screen.
Expose the test area with any positive
Cover half of it with cardboard or aluminum foil and slowly walk outside.
Rip off the cover and wash it out.
You are using the fastest (non-projection) emulsion designed for low energy exposure units and exposing it to sunlight, the most powerful UV energy source. Don't let it bother you - This is a once a week Tech Question.
When you finally buy a Stouffer T2115 Gray Scale US$10 to measure exposure, you can do an actual exposure test outdoors.
Lye, caustic soda, sodium hydroxide is overkill for a plastisol shop
Quote:
Originally Posted by rhilferding
The tape is causing the ink to crosslink - essentially "curing" it in the screen.
Of course, we don't know what tape he's using, but cross-link and curing are awfully strong terms to use for an adhesive to somehow cause the poly vinyl chloride resin ink that would somehow bond to polyester - and then, somehow break that cross-link with lye/caustic soda/sodium hydroxide. What adhesive can do that?
Yes, haze removers designed to attack DRIED, weather resistant solvent ink haze will remove plastisol ink that wouldn't harm a fly. It's like salad dressing.
Beware, oxidizes fast and has a very short shelf life. Beware, sodium hydroxide causes severe burns so don't get any haze remover on your eyes or skin - or call the manufacturer when your mesh pops. It's caustic.
It requires a UPS hazard fee as a Class 8 Corrosive liquid.
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How are you measuring? retired Ulano Technical Support Screen printing since 1979 - SGIA Academy Member
Last edited by RichardGreaves; June 27th, 2011 at 06:51 PM.
emulsion washes out where "haze" is 
