# Emulsion bubbles over time



## SixFootSouthern (Aug 18, 2016)

We have had a recent issue pop up in on our screens that I have not been able to solve just yet.

How we prepare:
Clean screens including degreasing
Apply textil Phu 1/1
Allow to dry overnight in around 50% humidity with fans blowing(Florida)
Using 156 and 110 mesh counts
Expose around 6 minutes ryonet rxp

Exposure times have gone way up recently as has our washout times using a pressure washer. Now our screens bubble out and the emulsion has dissolved on one side of the screen

Completed a CCI 5 step wedge test today with almunim foil covering sections that weren't being tested. 

The results are as follows 
9 minutes-three minutes of washout time ain't happening but no color change on .75 of 9 minutes which puts me right about at 6-7 minutes but still VERY hard to wash out
4minutes-color change on all except the 1.0 step washed out nice-ish
1 minutes- bubbled to hell in the middle part you can peel it off but again color change on all except 1.0

My question is if 6 minutes is supposed to be my time why is it so hard to wash out and why do I still get bubbles in the design?

We are 4 inches away with the pressure washer for more than a minute after wetting both sides and allowing it to sit for a minute.


Thanks in advance for any advice.


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## punkpatches (Nov 26, 2016)

I had problems with peeling and bubbling and found that getting as low of a relative humidity as possible was my answer. When winter came around i had temperatures of about 40 or so with a humidity of 70-80% so I put a fan in my box sucking air in and place a space heater in front of it on full blast to bring that humidity down. I noticed you said you have a reading of about 50% humidity so that may not be your issue, but if at all possible try getting in the 30-40% range and see if you get better results that way. Also if your bringing the humidity down to get the screens dry, it needs to stay down or the emulsion can absorb the extra humidity in the air. 
Now I just turn my fan and heater on about 30 minutes before coating to get the temps up and humidity down and dry for about an hour and I am good to go. Before I couldn't expose one screen properly.

That was just my experience for the bubbling/peeling at washout though. Also, you can spray your screens inside and let it sit for about two minutes before washing out. I use Ulano Orange, expose for 43 seconds on a DIY blacklight exposure unit, spray water with a water bottle on my design and let it sit for two minutes. I take it outside (full day light) and wash it out and put it in front of a fan to dry. Me spraying the screen to it drying is about a 3.5 to 4 minute process, including the 2 minutes spent sitting there.


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## SixFootSouthern (Aug 18, 2016)

For anyone looking to solve this:

Emulsion thickness was the answer. Our screens were slowly getting thicker without us noticing. The coating was also generally uneven. It explains why we were having to increase our time, still have trouble washing out and then have the other side melt away and bubble. 

More pressure while coating gave us thinner screens. 

In order to solve this I set up 5 screens testing one or two variables that helped me eliminate until I got down to thickness. 

I just got a 21 step in that I'll be testing next week!


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