# Need some help - cold weather emulsion issues



## Bonelafide (Aug 2, 2009)

Greetings! 
Heres my situation. 

I use Ryonets Hifi emulsion (I like the blue , and I have a Lawson vacuum seal exposure unit from some years back. (one of the large ones that can fit up to 2 standard screens, with the timer and all that stuff) With my exposure unit + the HiFi, I burn images anywhere from 55s-60s and have never had any issues so far. I've used strip tests to calculate proper exposure times. Through out the summer it was always spot on. However, now that cold weather has hit my side of town here in Tennessee I'm having issues burning/washing out my screens. 

Earlier today I burned two screens of a 3 color job. One screen came out fine. The other however began breaking and washing out. I thought perhaps it wasn't dried enough? 
(I let them dry in a covered drying rack over night in the garage.) 
I waited until later in the night to try burning two others. I have to wash out my screens outside in a washout booth. It was about 43degrees and for whatever reason, both images began washing out. So thats 3 screens today that did not properly wash out and I have no idea why. 


So, 

1. I dry my screens over night in the garage. (perhaps there's not enough heat to properly dry since the garage tends to get cold; It's weird how the one screen did manage to washout properly while the others did not?)
2. I wash out my images outside. The first was around 3 , no sun, about 48 degrees or so. The other two were at night in about 43 weather. 
3. My pressure washer is currently broke and shoots out a stream which takes time to hit all the spots needed to wash out. perhaps that could be an added factor with the cold weather, or the cold drying conditions.


I'm hoping someone could help me figure out a good way to be able to continue to properly expose screens & wash screens in cold weather, or what do you suspect my issue is? 


I will re-coat more screens and let them dry over night, however I'm going to try and wash them out inside the house in my bathtub just to avoid the cold weather and hopefully that will work. But I'm not wanting to have to do this everytime, so I'm open to ideas and suggestions.


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## Celtic (Feb 19, 2008)

Hey Ronnie, 
I don't think the problem is with rinsing outside. I'd say it's that with it cold in your garage, your emulsion isn't drying thoroughly.
If you can move them inside your house, all the better. If not, maybe try to warm that area in your garage...


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## sben763 (May 17, 2009)

Here is why. Humidity, humidity humidity. The HI-Fi is a rebranded CCI and it the HPV I belive. I used it and everytime the humidity was up and I had no dehumidifier going it would fail. Humidity is best removed when warmer air is present you can dry a screen @50F at low humidity 30% in a 3-4 hours where as you can dry a screen at 80F at 40% in 60 min. The HI-FI is very temperamental with humidity. If your not using a dehumidifier then I suggest using a emulsion like Saati Chem PHU that isn't as temperamental to humidity and is very similar to the HI-FI.


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## DigitalInkArts (Jul 20, 2011)

My times have changed drastically with the cold. I keep it 60 degrees and still I am adding a full minute to my exposure times. I see they have many types on the saati site. Which is best?

Sent from my SCH-R970 using T-Shirt Forums


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## Bonelafide (Aug 2, 2009)

So since I still have a full gallon of Hifi, and I do not have a dehumidifier at the moment... what would be my other option(s)? 

Figure out some way to dry my screens indoors until warmer weather returns?


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## sben763 (May 17, 2009)

Use a small 1500w heater. Just be careful not to get screens/emulsion above 100F. Even then I found too many inconsistent result with the HI-FI. If your using a blackligh unit at that temp your bulbs will be very reduced output.


Saati Chem Textil PHU. Spot color Supply has it.


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## Bonelafide (Aug 2, 2009)

I'm definitely going to check out that Saati emulsion (ill just use the rest of the Hifi though).

I did manage to dry them indoors and they worked perfectly! 
It's pretty difficult to keep a consistent set up working out of my parents garage. 

But thanks for the help and input.


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## porkchopharry (Mar 4, 2012)

Like Sean said, it's humidity. If I need screens I try to coat them in advance when it's cooler so they have a few days to dry. I've noticed some of them don't fully dry even then.

I have a small heater fan that I used to use on LOW to blow over them. Have to use care though for obvious reasons. But it works (worked) a treat. 

Like Sean, I use Saati PHU as well.

FYI - I wash out all my screens outside, even in the blaring California sun. Never had an issue ever. I do spray down both sides of the screen with water in a mister bottle after it comes off the exposure unit, and let it sit for a few minutes, before it goes outside though. Dunno if that just helps to wash it out quicker, or if it "protects" it from exposure in the sun to be honest. Some people have said that misting it down with water protects from further UV exposure (after you expose and before you wash out), but I don't know how true that is. It seems to "soften" it up pretty well though and make it easier to wash out. So whatever it does, I keep doing it because I rarely have issues with washout. Unless I coat a screen and it sits for months in 100+ degree heat.


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## sben763 (May 17, 2009)

With the Saati PHU or any photopolymer if you don't spray down before taking outside it wouldn't wash out. My water broke a few years ago and I didn't have time to fix so I took a screen to the door and sprayed with a hose. Couldn't have been 5 sec and it wouldn't wash out. I sprayed the next one and washed out fine. 

Water slows the cross linking or even stops it. This is why when the emulsion isn't fully dry it causes the emulsion the under expose


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## porkchopharry (Mar 4, 2012)

I usually mist down both sides real well, then let it sit inside for a few minutes. When I say mist, I mean I'm actually soaking that sucker down. But with a mister bottle. Gently...

Then, I take it outside, put it in my ghetto washout sink and mist it with the hose or power washer (lightly) again both sides, to make sure I covered/misted it completely, and let it sit for a couple seconds. Then, it always seems to wash out perfectly. Might be overkill to mist it a second time, but it works for me. So I don't mess with my mojo.

Funny, I don't think I've ever read the user sheet much for any emulsion. Only thing I paid attention to on the PHU was "very water resistant after post exposure" and something about "pressure washer".  I never even used a pressure washer before I got the PHU to wash out a screen. My garden hose is pretty high pressure. Probably don't need I guess, but I still ain't messing with my mojo.


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## dial911forme (Sep 22, 2014)

I give my vote to Saati. Very forgiving emulsion. Esp if you don't use a dehumidifier.


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## miktoxic (Feb 21, 2008)

if you're not in a crunch for time why not let them just dry longer?


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## Onewithpez (Jul 14, 2011)

Agreed if you are having issues with humidity you can have them site longer. Even after the screens are dry, they can reabsorb humidity from the air. I have my washout both sitting right next to my drying cabinet as I don't have a "dark room", but I have never had a problem as it is very dry here in Colorado. 
But the last shop I worked for, thy had converted an old walk in fridge into the dark room and I constantly had problems with exposure. There was just too much moisture in the air and even though the screen feel dry, that can still hold a lot moisture.


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## Onewithpez (Jul 14, 2011)

I also want to add you want to be careful about fans blowing over wet emulsion. That is a good way to cause pinholes from dust. Also heat can cause the cross linking in the emulsion and "expose" the screen as well.


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