# emulsion coming off during first wash out



## RaiderFred1 (Nov 14, 2011)

I am having problems with the emulsion coming off of my screen after 1st use. I have printed 2 other designs with no problems. The one I'm having trouble with has finer detail than the other 2. The emulsion always seems to come off on this desing. I have done it about 3 times.

I am using dual cure emulsion (from Ryonet) on a 20 x 24, 156 mesh screen. On the first 2 tries I coated it 1 & 1 and exposed it for 25 mins with a 500 watt light at about 20 inches away. The 3rd time I coated the screen 2 & 1 and exposed it for 30 mins. which seemed like I over exposed it cause i had trouble washing out the unexposed emulsion.

I printed 2 test shirts using white water based ink. I then tried to wash the screen off on the press using a spray bottle. as I rubbed (with a wet rag) the botton of the screen the emulsion on the small, detailed parts began to come off.

The emulsion is less than 1 month old & under-exposure might not be the case. What am I doing wrong? PLEASE HELP!


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## splathead (Dec 4, 2005)

How are you degreasing your screens before coating? If the design washes out OK but starts to degrade during use it could be:

1. You are not cleaning your screens correctly before coating. Or

2. You are using a non-waterbased emulsion with water based inks.


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## superD70 (Dec 22, 2010)

also you should post expose your screens, set them outside in the sun for a few min after washout.


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## ScreenFoo (Aug 9, 2011)

I'd just add--the thicker the stencil, the more rinsing it will take to develop-- you could quite possibly have still been underexposing. If you don't have problems with screens you coated 1/1, but do with 2/1, I'd be leaning towards exposure time as the first factor to look at.

Also, if you're going for detail, it is easier to achieve with a thin stencil. Of course, it won't be as easy on you when you get to press, but there's always a trade-off.


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## RichardGreaves (Nov 7, 2006)

superD70 said:


> also you should post expose your screens, set them outside in the sun for a few min after washout.


If you have dissolved all the stencil that didn't get cured with UV energy, what un-reacted sensitizer is left to cure with another few minutes of UV exposure?


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## RichardGreaves (Nov 7, 2006)

RaiderFred1 said:


> I am having problems with the emulsion coming off of my screen after 1st use.
> 
> I have printed 2 other designs with no problems. The one I'm having trouble with has finer detail than the other 2. The emulsion always seems to come off on this desing. I have done it about 3 times.
> 
> ...


Emulsion is easy. If you don't expose it with enough UV energy to cross-link the sensitizer, it will dissolve with water and rinse down the drain.

Dual cure emulsions are sensitized with diazo and are fresh for about 4 to 6 weeks before they require more exposure than fresh sensitizer to cross-link. They still work, you just have to modify your exposure time to get the same cure.

I don't think you have a degreasing problem. Liquid emulsion surrounds the mesh like handcuffs on your wrists, that won't fall off no matter how greasy your arms might be.

If you only partially expose the stencil the inside (where the water-based ink goes), will still be raw and the water will attack and breakdown the stencil. You will then start to rub the inside with a giant rubber eraser (squeegee) and the stencil will fail.

You are guessing at exposure times so call Ryonet and tell them that someone there sold you emulsion but didn't check to see if you had any way to measure exposure. Shame on them. Ask for a Stouffer T-2115 guide to measure stencil hardness. US$11.00
http://www.silkscreeningsupplies.com/product/REQC200003

I assume you are using a household 500 watt incandescent lamp that outputs very little usable UV energy for curing stencils so you have to expect long and longer exposure times.

*Homework*
Exposure FAQ Screen Making Products how to measure exposure


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## superD70 (Dec 22, 2010)

RichardGreaves said:


> If you have dissolved all the stencil that didn't get cured with UV energy, what un-reacted sensitizer is left to cure with another few minutes of UV exposure?


Because I believe under exposure is his problem, much as you do.
When I was using a halogen light I noticed the outer edges of the screen were always underexposed, made reclaiming a PITA sometimes, some one suggested post exposing them after I rinsed out the screen to fully cross link the emultion, worked like a charm


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