Screen exposing/wash out problems HELP!

[Shanarchy]

Hi Gang,

I need help on this one. Badly! I have been battling this issue for way too long and I'm at my breaking point. Every time I think I have an idea of what is causing it, it seems like it must be something else. Is hould have psoted here months ago but I know there is not many other cap film users here, and it seems like an embarrassing newbie issue.

When I'm washing the screen out the stencil starts to breakdown. Except I'm 99.99% positive it is not underexposure. Attached is a picture of the issue.

Emulsion: Ulano EZ orange capillary film.
Screens: Shur-loc EZ frames with S mesh (150/48, 180/48, and 225/40)
Exposure unit: Nu-Arc msp3140 with a new(ish) bulb

I've been using Ulano film for over 10 years without any issues. I've also double checked my exposure with an exposure calculator and even went as far as to double the time that has been working for me for years. I also checked the batch numbers with Ulano to confirm that these are not old expired film I keep getting.

This problem started when I got rid of my Newman's with regular mesh and switched to EZ frames with S mesh. My original thought/concern was there may be an adhesion problem to the thin thread mesh. Both Ulano and Marukami say's that should not be an issue.

I recently used a mesh abrader (Ulanogel #23) even though Murakami said it would be a bad idea and could weaken the mesh. No dice. I've also used Ulano magic mesh pres, and also Satti direct prep 2. No dice. None of these I ever needed to use before anyways.

This is happening on all my screens so the thought of some kind of foreign substance being on the mesh is very slim. Unless they are all shipping that way from Muarakami and/or Shur-Loc (highly doubting that).

My latest thought is that there is diptank solution not completely washing off the screen and as the screen is being wet during wash out, it is causing the dried solution to become wet and start attacking the film.  However this was never an issue before. Could the solution be getting trapped in the channels (where the mesh locks in) and dripping down when wet? I've also switched to a new power washer and am no longer using a box store one. Could there be too much PSI and it is not properly washing/rinsing the screens?

I spoken to people at Ulano and Muakami. Both very nice, but are suggesting using different products, etc. Some I have tried. But if I never had this problem for over a decade I find it hard to believe it's the products I use, or don't use. Unless, of course, the S mesh were to need a special product.

In the picture you can see the image washes out on the screen fine, except there is an area with the film pulls away.

Help! I'm giving up hope here.

[GKitson]

I have got to think you are not adhering the cap film completely to the mesh.  Capillary action should draw the mesh into the mesh and fully encapsulate the threads.

Give us an example of how you are wetting/adhering the cap film in a step by step or better yet shoot some video and put it on youtube for analysis and comments.

My 2 cents

[Frog]

Yes, it certainly looks like it was not adhered well where it bubbled, but that does not explain what has changed.
I still wonder if screen contamination could cause this as I am not a cap film guy, and have no hands-on experience.

To eliminate the contamination issue, how about trying a brand new screen (or panel)?

[Shanarchy]

Thanks for the quick response guys! You're two people who's opinions i highly value. When I get to my computer I'll post a detailed step by step and also work on getting a video of the process.

My main thought is that if I am doing something wrong in the process, which I could be, how have I never had this issue in all these years?

better detailed response to follow.

[Homer]

you've been using cap film for 10 years, you know how to use it. I wouldn't question that at this point, I would question the cap film. Coming out of winter, is there a chance it froze and turn bad? try another roll maybe?

[3Deep]

Could be in the chems that your using now to reclaim your screens causing the cap film not to stick to the mesh, or new mesh that has not been degrease/abrading...Homer might have hit the nail on the head with bad cap film.

[Shanarchy]

OK, I'm at a computer (vs my phone) and can put a thorough post.

I'm pretty sure it's not a cap film problem. This issue has been going on for several months. I spoke with Ulano and gave them batch numbers to which they confirmed the film was relatively new and no where near being expired. This issue has been going on before the winter so the temperature shouldn't be an issue. And our shop is (almost) never under 60 degrees.

Step by step reclaim/coating procedure:

-card all ink into ink containers with ultimate clean up card

-remove screen tape

-drop into diptank with Easyway Supra

-remove screen after a few minutes (at point where emulsion/film is very soft)

-Stand screen up on diptank lid to allow extra solution to drain off to be poured back into diptank

-powerwash the shirt side of screen on a fan spray with AR Blue Clean 630 pressure washer

-turn screen around and power wash the inside of the screen with a fan spray

-adjust pressure washer stream to blast out any stubborn spots

-spray Easyway 901 on inside of screen, scrub with a beige scrub pad (sold at my supplier), then scrub the shirt side of the screen

-let the screen sit for a couple of minutes than power wash on fan spray the inside of the screen, adjusting the spray if needed, then the outside. I go back and forth (left to right) on the shirt side of the screen on fan spray from top to bottom

-take sheet of capillary film and apply it to the back of wet screen, wet mesh pulls the film into the screen. Quickly run my hand over the back of the film/carrier sheet, then turn the screen around. You will be able to see dry spots anywhere on the inside of the screen if there are any. Usually there is not. I give a light spraying with a water bottle. Then take a squeegee and do a stroke from bottom to top twice (once on the left, once on the right to cover all of the film), then give two squeegee strokes to the inside of the screen  (left and right again)

-set the screen to dry inside drying cabinet with heat setting at 2 (very low).

-screens are usually allowed to sit 24 hours before being used

-peel the carrier sheet off

-I rub a light dusting of powder on the screen so the film does not stick (summer time/humidity issue)

-expose, place screen in washout booth, light spray to the inside of screen (which I have refrained from doing since this issue started to happen regularly, spray the outside of the screen, let screen sit a couple of minutes, spray the outside again, let sit a minute, wash out entire image

This is how I've done it for over a decade. There could be steps that are not done perfectly text book, but this method has always worked with no issues in the past.

Please note there is no degreasing, or apply mesh prep in this step by step. I stopped doing both years ago and never had one issue. I have recently tried a few different ones at the advice of Murakami and Ulano. It didn't solve the issue.

At this point I only see 3 realistic reasons:
-S-mesh issue with capillary film. The thin threads make it more difficult for the capillary film to properly adhere. Both Ulano and Murakami said this should not be the issue

-New mesh issue. Mesh need to be treated/abraded/broken in to obtain proper adhesion. Murakami says do not abrade. Ulano said there abrader will not damage the mesh. A round of abrading with Ulanogel #23 didn't seem to help.

-EZ frame frame issue. The channels trap dip tank solution which mix with the water during screen wash out and then come into contact with the cap film during wash out causing the film to bubble (or whatever you want to call it). That said I have been spending a lot of extra time trying to make sure the screens are properly rinsed. But I may be leaning towards this.

I'm now thinking about ordering two new static screens. One with S mesh, one with normal mesh, and take an old screen off my shelf and try exposing a screen on all three. This would hopefully establish whether this is a new mesh, S mesh, EZ frame, or an issue that has nothing to do with the mesh or frame.

Any thoughts and feedback on this is greatly appreciated. I will try to take a video soon.





chemicals are the same we've been using for at least 8 years. Easyway Supra in the diptank, 901 sprayed on, scrubbed

[Colin]

Your only change in all this is - going to a thinner thread.

I would look at whether or not you have full encapsulation of the threads on the squeegee side.

It is "possible" that you have not pushed it through far enough to hold onto the thinner threads.

I also know from experience.... not all emulsions like thinner threads.  The only ones I have found that really work well are those that have a "harder" finish.  I.e. that are not as flexible.  Hard to describe well, sorry.

I know the pourable orange emulsion is a softer emulsion, I did not like its performance on thin thread.  Standard thread was ok...

TLDR:  Double check that you have full encapsulation and your screens are at optimal dryness.

[Shanarchy]

Your only change in all this is - going to a thinner thread.

I would look at whether or not you have full encapsulation of the threads on the squeegee side.

It is "possible" that you have not pushed it through far enough to hold onto the thinner threads.

TLDR:  Double check that you have full encapsulation and your screens are at optimal dryness.

Possibly the way I've been applying the film worked for regular mesh but won't on thin thread? By not fully encapsulating are you suggesting more water, or more pressure to push the film into the screen?

[Frog]

I have to assume that upon close examination, perhaps with the aid of a loupe, proper application and full encapsulation would be visible and able to be confirmed.
Do you have any older screens with which this could be compared?

[Underbase37]

I agree with Colin. The variable that seems most likely is the thin thread.

One thing that jumped out to me was that you said you no longer rinse the inside of the screen bc of this problem.
To me this sounds like classic under exposure.

So a few quick thoughts.

Was the old mesh yellow too? If not maybe try adding some time to exposure.

Is the cap film maybe to thick? If so adding some time should help.
*-we're not using cap film, but we had to make changes to our coating techniques bc of EOM thickness on thin thread.

Murphy

[Printficient]

The one thing I would do is take a garden hose with a spay nozzle set on shower and thoroughly rinse the screen before application of the film.  Think of it this way, your pressure washer is using very fine droplets at a high rate of application.  These are also light weight.  The shower setting will bombard the screen with heavy large water droplets at a slower and more dispersing rate.  This should wash out any residual chemistry. If you drop a single drop of water on someone then no harm no foul.  Drop a water balloon on someone and you better run.

[GKitson]

Have you started or stopped using a water softener, or perhaps been using a softener and allowed it to run out of salt.  Looking for changes that may have occurred which you have not linked to the issue yet.  Think soapy water in a shower and how the softness of the water affects bubbles, this is a surface tension issue.

Capillary film is dependent on water being held in the mesh via surface tension of the water, the thing which allows bugs to walk on water, and if that surface tension is inadequate your mesh will not hold the water to allow the capillary action to be effective.

On that same theory the thin thread will increase the theoretical open area of the mesh and the surface tension may not allow the cells to hold water for proper capillary adhesion.

Applying cap film to 60 mesh is a problem for the same reason but is much easier to understand when you can see huge holes in the mesh.

GREAT CONVERSATION

[GKitson]

-EZ frame frame issue. The channels trap dip tank solution which mix with the water during screen wash out and then come into contact with the cap film during wash out causing the film to bubble (or whatever you want to call it). That said I have been spending a lot of extra time trying to make sure the screens are properly rinsed. But I may be leaning towards this.

If you are not being very careful chemical laden water that is trapped in the channels may be dripping back into the mesh area and causing the adhesion issue.  Each time you flip the screen little drips/streams of contaminated water could be being redeposited on previously clean mesh areas.

This may be your ultimate culprit, allow your screens to completely dry and re-wet to apply cap film and see if the issue goes away.

My 2 cents....

[balloonguy]

 I would try a new degreaser.