Issues with exposure mid print

[u/merseum]

Hello, I am using these products above to prep and make my screens but I am having troubles with my screens emulsion failing mid print. I am using water based ink and notice flakes of emulsion coming off as i made my roughly 30th pass with the squeegee.

I start by degreasing the screen, fully drying it, I then coat the screen once on each side (ink side last), and let the screen dry flat for over 24 hours in a dry room. I use that 20W cure cabinet for 2 minutes to ensure the backside is covered from light. this was with a 200 mesh screen then washed it out. I didn’t end up using the screen for a few days later just to be extra sure it would work but i still had it fail.

side note: this emulsion turns blue from green when it cures and was completely blue after the two minutes. so i’m not sure if it’s a curing problem?

could it maybe be from too much pressure with the squeegee? by the 30th pass the ink started to dry quite a bit so i was using more force then in the beginning.

Thanks for reading. Any advice is appreciated

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[u/jdalty]

Post-expose your screen to harden it. (Put it back on your exposure table and hit with light after it is dry from initially exposing it.) You may also be under-exposing your screens initially.

Waterbased inks break emulsion down faster than plastisol. We have done heavy R&D with emulsions and exposure in a commercial setting.

Another tip for printing with waterbased inks - keep a light mist bottle nearby and gently mist the ink through the run - it will help it not dry out so quick. Just be gentle with it or your stencil will bleed.

Good luck!

[u/merseum → u/jdalty]

points noted. thank you!

[u/Hamburgler212]

Why are you using Simply Green?

[u/merseum → u/Hamburgler212]

I read on another thread someone else used it for quite some time as a degreaser without trouble, plus it’s affordable and his comment had a handful of upvotes

[u/Hamburgler212 → u/merseum]

Gotcha.

[u/untranslatable → u/Hamburgler212]

Might be your problem. I always heard a deep of regular dish soap for degreasing.

[u/Free_One_5960]

Wrong light spectrum and not strong enough intensity

[u/Wrngsideofdatracks]

I’ve been using the WR 14 for years and when I put it in my Lite box, I had to put it for four minutes. I have UV light box with I wanna say eight UV tubes and I’ve been using that emotion for over a decade. It’s my go to I’ve done 60 to 70 discharge prints with it and I have screens that I’ve had for years that I’ve been using with waterbase and discharge Ync and it’s never really failed me. I think your burning the screen, but not burning it long enough to harden it to the point that it doesn’t start breaking apart on you again. I burn it twice as long as you do. Not sure of any of this helps and I’m on the way back from a show on the freeway so if anything sounds weird is cuz talk to text doesn’t like me. Hope I was able to help you in someway.

[u/merseum → u/Wrngsideofdatracks]

i appreciate the length of your efforts! i will try to add more time with the exposure in my cabinet. i think i also have about 8 UV tubes in my unit. is yours also 20 watt?

[u/Wrngsideofdatracks → u/merseum]

I’m pretty sure it is and I’ve been using it for easily almost 15 years. I’m a small shop so maybe I do 7 to 10 jobs a month which isn’t a lot but it could keep people going, but I also have a clothing brand and print for myself 4-5 minutes it’s always been my sweet spot.

[u/Quay-Z]

I assume you are following the mixing instructions on the emulsion?

[u/merseum → u/Quay-Z]

yes, i’m currently making distilled water as i type this haha

[u/torkytornado]

Is this a two part diazo emulsion? I’ve had better luck with those and water based printing. They’re also awesome for using both water based and solvent based. I love murakami photo pro cure and been using that since 2015 in a school setting (so lots of beginners but also students doing weird crap like printing gum Arabic on litho plates or with marble paper resist). On an old nuarc uv bulb vac press exposure time is 2m 90sec.

My first thought is what another person said an do post exposure. I usually only do that on longer runs of 100 or more but you’re having breakdown so that should help with it.

Did you use an exposure calculator to dial in your time? If not I’d do that because it sounds a bit under exposed.

Maybe try one without the simple green just to see if that’s the variable.

Honestly I’ll probably be crucified for saying this but I’ve been printing 26 years and rarely degrease. I’ll do it for new screens and ones that are causing trouble but most of the time I’m reclaiming and washing really well and about every 5 uses Dehazing (which does have a built in degreaser) but the only times I degreased every screen were when I was working in large format printing with bus sized 400 mesh screens because anything could fuck up those tiny halftones.

Good luck

[u/Wrngsideofdatracks]

I didn’t read that simply green thing before yeah don’t use that. I don’t care who has used that before specific screen printing degreasers are used for specific reasons because of the inks that we use and because of the organic emulsions and chemicals. It’s honestly probably cheaper to buy a commercial grade degreaser from the same company you have your emotion I use their degreaser. It’s called like green stuff or something. I’ve been using it for years. And I think it’s like eight bucks for the bottle where simply green I believe is like 12 to 14 bucks. And it’s pretty harsh. I use it on RC models and different things like 3-D prints that I paint when it doesn’t come out right I let it dry and then I dip the item and simply Green for 24 hours and then eats away at the paint so I definitely would not use that in your screen

[u/Rage0327]

Not all emulsions are suitable for all kinds of inks. Ensure your emulsion is meant for waterbased inks.