Accidentally used tap water in emulsion

[pdslevin7]

Hi all

Sooo, I think my emulsion is screwed!

I'm using SAATIchem Water/Solvent/Discharge resistant emulsion and the stencil won't wash out even after being under a UV lamp for 15 mins (it usually only takes 12).

The only thing that I can think of is that I used tap water to mix the sensitizer powder instead of distilled water. Can that make much of a difference?!

I've used the same emulsion before and when I mixed it with distilled water, it worked perfectly.

The first time I used this batch (the tap water one) it was OK but it seems to be getting worse every day.

Is there anything that I can put in it to make it work properly?!

Thanks! (I'll post this in the Saati section too)

[pdslevin7]

Hi all

I should probably add that I used this same tub of emulsion about a week ago and it was fine.

Also, the emulsion washes out on the substrate side but not on the squeegee side.

When I try to wash it out of the squeegee side, it goes really 'webby' and kind of stringy

I tried washing it out with a pressure washer and it works but then washed out parts of the stencil that aren't meant to be washed out.

So confused!

[Saati]

Ok let me put the tap water myth to bed. Basically the emulsion is made to tolerate a range of ph found in most of the worlds water supply. A good rule of thumb is if you can drink it safely you can use it to mix the emulsion.

With that being said I would also like to comment that the emulsion has no brain and cannot be a disgruntled employee so it will do as it is told. So if today it does not work but yesterday it did something changed in the process. So lets take a step back and a deep breath and look at the facts.

You say the emusion is washing out stringy... this is usually means it was getting exposed through the film positive. an easy way to rule that out is to take a standard buisness card and place it on the next screen (act like it is a positive) and make your normal exposure. if it washes out fine then it is a positive issue. if it washes out stringy then the screen is getting pre exposed somewhere.

check it out and let us know what you find out.