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!

[ApeShirt]

So am I. I'm really confused by what you mean that it washes out on the substrate side but not the squeegee side. If it washes out, it washes out. I wet both sides of screen but only washout from the substrate side. A dual-cure emulsion will be slimy on the inkwell side. It's hard to tell from your posts but maybe you overexposed. That's what usually cause emulsion to not washout of the stencil area. Can you post a picture(s) to show what you are referring to?

[pdslevin7]

Hi ApeShirt - thanks so much for your reply.

When I say it washes out on the substrate side but not the squeegee side (I was told by the company that I buy all of my screen printing stuff to wash out on both sides) I mean that the emulsion goes from pale blue to pale yellow on the substrate side (it's as if a layer of emulsion has been stripped off) and then when I flip it over to wash the squeegee side, nothing happens, it stays pale blue.

After pointing the water hose at the screen for about 2 mins, the emulsion comes off in parts to show the 'vibrant' yellow of the screen but it's mainly just not washed out.

I hope I'm making sense, but if not I've added pictures to show you what I mean. (There's loads of ink ghosting on the screens, please ignore!)

Thanks again for your help

Image is of the substrate side

[pdslevin7]

Can't figure out how to attach multiple files in one go so adding them individually

This is the squeegee side

[pdslevin7]

Squeegee side

[pdslevin7]

Substrate side