My screen wash is removing my emulsion!

3915 Views 17 Replies 8 Participants Last post by lazerstruck, May 7, 2014

lazerstruck

Discussion Starter · Apr 14, 2014

Hello again!

I've scoured the internet for this issue... I thought for sure someone would have had this problem before, but I'm not seeing anything.

I'm super frustrated at this point. I FINALLY got a screen properly coated, dried, and burned. I set up on my press and started printing - things were going perfectly fine. I accidently hit the collar of a shirt and displaced some extra ink on the print-side of the screen. No problem. I pull out my 'Chroma Screen Wash 920' and wipe down the problem area. I then notice blue residue on the rag (my ink is white). I rub a little more and notice the emulsion is wiping away. HHNNNGGGGG!

I've checked the manufacturer's website, and the screen wash says it works with plastisol inks. Any clue what's going on? The emulsion is 'PC701 SBQ POLY CURE Emulsion'.

Thanks!

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outbreak

· #2 · Apr 14, 2014

When you rinsed your screen after exposing, was it slimy? I'm wondering if it wasn't exposed enough. I always stick mine outside in the sun after exposing and rinsing. It dries the screen and the sun's UV's completely cure it in case it was slightly under cured.

Reactions: 2

sben763

· #3 · Apr 14, 2014

Or after dry post expose the screen from the ink side if sun is not avalible.

lazerstruck

Discussion Starter · #4 · Apr 14, 2014

outbreak said:
When you rinsed your screen after exposing, was it slimy? I'm wondering if it wasn't exposed enough. I always stick mine outside in the sun after exposing and rinsing. It dries the screen and the sun's UV's completely cure it in case it was slightly under cured.

I don't know what you mean by "slimy". The stencil was neck tags, so there is very small text - they washed out fine, so I'm assuming the exposure time was good.

I did take it outside in the direct sun for a few minutes. The emulsion exposes in 2 minutes under black lights, so I figure a few extra minutes post-washout in the sun is plenty.

Is it possible this screen wash is too strong? Perhaps it should be watered down or something? I've read the instructions thoroughly. Nothing really applies to this issue.

sben763

· #5 · Apr 14, 2014

If the screen was still wet taking in the sun does almost nothing till dry. What emulsion. It's possible it's not compatible but more likely it was under exposed in the first place.

lazerstruck

Discussion Starter · #6 · Apr 14, 2014

The emulsion is 'PC701 SBQ POLY CURE Emulsion'. The screen was dried over night after washing it out before it was placed in the sun. Maybe I need to dry it longer before burning? I let the emulsion dry for 3 hours before I burned it. It was solid, like plastic, and not tacky at all.

sben763

· #7 · Apr 14, 2014

Photopolymer/SBQ emulsion is humidity sensitive. It can be dry but if the humidity is above 40% the sensitizer doesn't cross link as fast. although post exposing will further harden the stencil, a severely underexposed screen will still be venerable. On a sunny day I will throw the screens out 5 min each side.

The tackiness would be during washout after wetting the screen both sided rub your finger on the ink side if its slimy your probably under exposed

Reactions: 2

dudefor20

· #8 · Apr 24, 2014 (Edited)

you need to let your screens cure longer...aka dry lol. How are you burning them? Let them sit outside in the sun before you put emulsion on them.

dudefor20

· #9 · Apr 24, 2014

degrease them properly before applying emulsion as well.

lazerstruck

Discussion Starter · #10 · May 5, 2014

Thanks for all the feedback guys.

After doing this process for a few weeks now (and over 15 screens), I'm starting to think the screen wash is the culprit. I've tried watering it down, but all that does is cause the plastisol to sort of congeal and smear around, only to harden again or sort of stain the emulsion. But it's STILL removing the emulsion. I'm allowing 24 hours for the emulsion to dry, burning properly (did 3 step tests to nail down the time), and then I put them back on the exposure unit or outside afterward.

I did a 200 shirt run this weekend and went to archive the job's screens today. The job was a 3-color setup. Two 140 mesh screens, and 1 200 mesh. After spraying on the screen wash, the 200 mesh emulsion loosened up almost as if I'd put stencil remover on it. Totally ruined. The two 140 mesh screens seems fine, until I went back and noticed small details around edges had flaked off. It's either a bad batch of emulsion or this screen wash isn't compatible (even though it was advertised to me to be compatible).

Emulsion: PC701 SBQ POLY CURE Emulsion
Screen Wash: ChromaScreen Wash 920

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Celtic

· #11 · May 6, 2014

Unless you are drying your screens (before exposing) in a forced air dry box, or live in an extremely dry, low humidity area, 3 hours just isn't enough time for drying.
Personally, I dry mine 24 hours before exposing.

dnicky928

· #12 · May 6, 2014

i am almost completely sure that your drying time is not long enough...what type of light source are you using to burn screens? And lastly, if all else fails get some screen hardener.

lazerstruck

Discussion Starter · #13 · May 6, 2014

dnicky928 said:
i am almost completely sure that your drying time is not long enough...what type of light source are you using to burn screens? And lastly, if all else fails get some screen hardener.

Just ended up having to power wash the screens out without the aid of reclaimer as it couldn't penetrate the film the screen wash and ink had left behind. Borderline screen locked. Took several minutes on each screen to get the emulsion out.

I dry fresh screen for 24 hours now in a dry box with a mini fan for air circulation. I'm using a converted light table fitted with 3 blacklight bulbs. After washing out stencils and drying the screen, I put it back on the table for about 5 minutes each side.

I never have any issues with the emulsion now UNLESS I spray that screen wash on it. I just read the item's description online and it says it contains a degreaser - is this screen wash meant for degreasing after removing the emulsion? I'm about to buy Citrus Paste - seems to be more of what I'm looking for. It specifically says it doesn't effect the emulsion.

lazerstruck

Discussion Starter · #14 · May 6, 2014

Celtic said:
Unless you are drying your screens (before exposing) in a forced air dry box, or live in an extremely dry, low humidity area, 3 hours just isn't enough time for drying.
Personally, I dry mine 24 hours before exposing.

I dry for at least 24 hours now. I built a dark box with a small fan in it. My garage isn't light-safe during the day due to sun light creeping in around the garage door sealing, so I tend to coat and/or burn screens at night, with 24 hours in between coating and burning.

These particular screens had been in the dark box for at least 3 days before I used them.

dbarry55

· #15 · May 6, 2014

How would you like to get away from using emulsion all together, go to youtube and watch "screening with vinyl", wish I had seen this video before I retired and got out of my shop, it would have saved me hundreds dollars and hours preparing screens, and I could have used this for over 90% of the work I did.

sben763

· #16 · May 6, 2014

dbarry55 said:
How would you like to get away from using emulsion all together, go to youtube and watch "screening with vinyl", wish I had seen this video before I retired and got out of my shop, it would have saved me hundreds dollars and hours preparing screens, and I could have used this for over 90% of the work I did.

Screening with vinyl works but for small runs. If your trying to do 100 shirts the vinyl quickly looses its edges and starts to loose detail.

It's not worth the hassle unless its a small run. Even then after trying I won't use it as once it fails there is no repairing screen.

tpitman

· #17 · May 7, 2014

It's probably under-exposed emulsion, or emulsion that wasn't dry enough before exposing as others have mentioned, but that screen wash is usually used in the sink prior to emulsion removal. I've washed and set aside screens for reprinting using EasiSolv 701 ink degradent (which is similar to what you're using) but if you're cataloging screens, get a press wash like PlastiSolv 820.
You also might want to try a different brand of emulsion under the same circumstances, just in case you got a bad batch.

Reactions: 1

lazerstruck

Discussion Starter · #18 · May 7, 2014

I contacted the company that sold it to me and it turns out the screen wash is a solvent, and this particular emulsion is not solvent resistant - thus my problem. I really like this emulsion, so I purchased some Image Mate Degreaser 260 (what they recommended) and Citra Paste. I'll see which works better.

Thanks for all the info! Think I've finally got this all down. Have a 4-color job to run today. Should be fine as long as I don't make too big of a mess!

Reactions: 1

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