# Please Help! Emulsion is not sticking to screen after exposure... no idea what is going wrong!



## LaughingTree (Aug 23, 2008)

OK so we've been trying to start a business screen printing for about six months now. We have managed to harvest two semi-successful screens in those six months. We have three jobs waiting in the wings and still can't get this straight, any helpful advice is appreciated. I really want this to work! Please Help! This is what we are working with: 

First we have degreased the screen with simple green, rinsed with room temperature water, and left to dry in our temporary make shift drying closet (a large cardboard box that has a filter duct taped to one end with a small portable heater outside of the box blowing warm air into the box, the other end has a fan blowing out air like an exhaust). We have left it to dry till it was dry to look and touch, this takes about 20-30 mins. 

After we have a clean dry screen we coat it, off go the lights. We use a scoopcoater to apply the emulsion. We are using Holden's 1 Way Emulsion 3000-DC, it is solvent and water resistant. We store the emulsion in a dark closet always at room temperature. We only coat the outside of the screen once, I am considering the outside as the opposite side you would use the squeegee on. We then dry it for an hour in our modest drying closet.

After an hour, the screen appears dry by the looks and touch of it so we expose it. We have built an exposure unit, I found the plans actually through these forums I believe : home built uv exposure equipment screen printing silk screen and screen print
When we expose the image we make sure to put some heavy books on top of the screen to make sure the image is flat against the screen and glass. We have tried a number of different exposure times, we have gone as far as making a test strip like you would in photography. After pulling out most of our hair, we found that our most successful exposures so far are under 10 seconds...

Now we wash the screen out. When we wash the screen out we start to see the image come through but the emulsion is shedding off like skin in areas that it is not supposed to. The emulsion just doesn't hold onto the screen. We are gently spraying the screen (outside first) and letting it sit for a few minutes (we have read that this may make it easier to rinse out). We have also tried not letting it sit, it still sheds like skin when the water hits it. 

We have worked so hard to give up now. I really can't understand what we are doing wrong. We have potential customers waiting for us and I really want to come through on this. Any suggestions or advice is very appreciated. Thanks for reading, I know it's long.


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## tdigital (Sep 14, 2008)

SHORT ANSWER: You're probably (most likely) underexposing.

LONG ANSWER:
1. Use a different emulsion, yours may be old. Matter fact, use a name brand emulsion from a screen printing shop. The key here is to eliminate as many variables as possible. 

2. Get an exposure calculator. 10 Seconds is in the 3,000 Watt Metal Halide range.
2.5. 1 hour probably isn't enough time to wait for it to dry after coating, but then again you don't know because you're not measuring your relative humidity in your drying closet.

3. Go on youtube and watch every single video about screen printing. The ones from ryonet are very good.

4. Use the forum search. Some of the grand wizards of screen printing have covered this very topic about 3,094 times in great detail, much greater than the detail i've give you here.

BIGGEST TIPS:
Measure everything you can and document what works and what doesn't. Your profitability will thank you.
Use the forum search.


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## LaughingTree (Aug 23, 2008)

What emulsion do you recommend?


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## tdigital (Sep 14, 2008)

LaughingTree said:


> What emulsion do you recommend?


Ulano QTX.

Do a search for "Richard Greaves" and read read read.


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## txjake (Dec 2, 2008)

You are taking far more precautions and being a lot more careful than I've ever been with a screen. I work out of a basement in an old building with an office supply upstairs. It's kinda damp in here most days... so controlling my humidity level is kind of a lost cause... but I turn out dozens of successful screens a week.

I have used Ulano QTX quite a bit in the past, but have had better luck with Kiwocol. The one I've settled on that works best for me and my situation here is the Poly Plus SWR. It requires adding a sensitizer, but costs a lot less than the Ulano.

I have an exposure table that uses UV lights... takes about 4.5 minutes to expose a screen.

I agree with the above assessment... you likely have a bad batch of emulsion, and your exposure time likely needs to be increased. If you have enough screens, I would consider coating up several and allowing them to dry overnight. I stack mine in a darkroom (though not nearly as nice as a photography darkroom) after coating on top of each other with a couple of aerosol can lids between them, and point a box fan at them. Once you have a few to work with, you can spend a day testing out various exposure times and see what works best.

The emulsion will make a difference on exposure time as well. Ulano QTX exposes properly at around 2 minutes on my equipment as opposed to the 4.5 for the Kiwocol... so regardless of which one you try, you'll have some adjusting to do.

Good luck


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## midwaste (Apr 8, 2008)

Also, you need to apply a coat of emulsion to the shirt side, and then another on the print (squeegee) side. The last stroke of emulsion should always be on the print side. 

I agree with the previous posters that it is highly possible your screens are not fully dry. Just because they are dry to the touch definitely does not mean that it's dry all the way through. Use a hair dryer, just keep the emulsion below 100F.
Use the hair dryer to dry the screens after degreasing and stop wasting time with a drying box too, for that matter.


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## raw191 (Nov 16, 2008)

I'm new to all this too, but you sound like you're having the same troubles I did. I found out I was putting on to much emulsion. I was using the round side of my coater, and switched to the sharp edge. Also, when you coat them, get with it. going up the screen faster seemed to really help. Good luck!


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## LaughingTree (Aug 23, 2008)

OK--so I let my screen dry overnight and printed out this step wedge calculator from this website How to Determine correct screen exposure times using Vellum 
I exposed the screen the way the directions advised and I think we're finally getting somewhere now! 

You guys were right, I was definitely under exposing. The step wedge developed best on the 64 second strip. I also think that my screen wasn't dry enough the other times. I'm going to repeat and see how it works out.

Thank you all for your posts they were really helpful .


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## txjake (Dec 2, 2008)

midwaste said:


> Also, you need to apply a coat of emulsion to the shirt side, and then another on the print (squeegee) side. The last stroke of emulsion should always be on the print side.
> 
> I agree with the previous posters that it is highly possible your screens are not fully dry. Just because they are dry to the touch definitely does not mean that it's dry all the way through. Use a hair dryer, just keep the emulsion below 100F.
> Use the hair dryer to dry the screens after degreasing and stop wasting time with a drying box too, for that matter.


I usually only apply one coat to the back side of the screen. I occasionally have a pinhole or two, but I've had far better outcome without coating the front.

It works best for me, but would be worth trying... what works for some folks doesn't work for others.


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## LaughingTree (Aug 23, 2008)

Coating only one side works fine. I don't think coating both sides will help anything, it would take even longer to completely dry!! 

I repeated exposure at 60 seconds with my design and it turned out pretty well. There were some fine lines in the design that didn't come through (but keep in mind my exposure unit isn't anything professional). I just thickened up the lines and will try burning again after screen is done drying. I think we pretty much figured it out, we just need some fine tuning in finding the sweet time for different kinds of images.

These forums rock!!


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## txjake (Dec 2, 2008)

Yes they do 

I started printing in 1994, and I learn something or find something extremely useful here almost every day


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## Brandz13 (May 14, 2013)

txjake said:


> Yes they do
> 
> I started printing in 1994, and I learn something or find something extremely useful here almost every day


I agree.. I am having the same problem with an emulsion I used way back when.. the ULANOFX88SRG I got this because it has the separate dye & Activator..I used this back in the early 90's. I didn't want to use the dye so I can see through it. because this was a ZERO tolerance 4 color process job. The emulsion keeps doing the same thing as Laughing tree says in this thread. it bubbles up and sloughs off the 305 screens. I have top notch equipment and many years experience. The screens are dried overnight, decreased and abraded. It is kicking my butt. I used a way cheaper "RED" emulsion and it worked amazing on the very fine "dot matrix" So what gives? why is this emulsion that is used for super fine detailed work not working for me now? TEACH THIS OLD DOG A NEW TRICK...


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