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screen printing => Ink and Chemicals => Topic started by: whitewater on June 11, 2014, 01:42:42 PM

Title: Black ink eating through emulsion...
Post by: whitewater on June 11, 2014, 01:42:42 PM
we use saati PV emulsion.  We use Union Black ink

Right now the black is eating through the emulsion after 600 shirts.

No other color is doing it, the black has done this once before on a long run//


Thanks

Rob
Title: Re: Black ink eating through emulsion...
Post by: KevWilso on June 11, 2014, 01:58:45 PM
Is this Union plastisol or water based black?

If it is plastisol your screens are probably under exposed.  Check your light source.
Title: Re: Black ink eating through emulsion...
Post by: tonypep on June 11, 2014, 02:03:07 PM
Its the carbon in black. Very aggressive.
Title: Re: Black ink eating through emulsion...
Post by: whitewater on June 11, 2014, 02:04:52 PM
plastisol...here is a pic...

if under exposed why are all the other colors ok?

even burned halftones after this screen and no problems.

So Tony, think the carbon?
Title: Re: Black ink eating through emulsion...
Post by: tonypep on June 11, 2014, 02:18:33 PM
Probably a combination of underexposure and the carbon being the most aggressive pig
Title: Re: Black ink eating through emulsion...
Post by: blue moon on June 11, 2014, 02:43:12 PM
how do you coat, what emulsion do you use, what do you expose with and how long?
it should give us an idea if it's potentially underexposed. . .

pierre
Title: Re: Black ink eating through emulsion...
Post by: whitewater on June 11, 2014, 02:45:47 PM
satti pv emulsion, cheap black light box, that screen was a 156, coated 3/3 , time....its on feel...LOL..we just have a 2 dots on the timer, one for 110.156 and another for our 230's

no other color does this.

I'll try to expose longer....we usually do not have this type of issue..
Title: Re: Black ink eating through emulsion...
Post by: abchung on June 11, 2014, 03:12:53 PM
For me, we wasted about 6 screens due to the mesh not being dry enough.

So may be the drying room humidity is going up due to summer, which slows down the drying process?
Title: Re: Black ink eating through emulsion...
Post by: Screened Gear on June 11, 2014, 04:48:35 PM
Quote from: abchung on June 11, 2014, 03:12:53 PM
For me, we wasted about 6 screens due to the mesh not being dry enough.

So may be the drying room humidity is going up due to summer, which slows down the drying process?

My guess is along these lines. I have never had a screen break down from plastisol ink. Pin holes open up on press yes but never breakdown. It has to be underexposure. Also coating 3/3 for a black screen is way over kill. That screen will need alot of exposure time to be fully exposed. So my answer is coat less let dry over night and make sure to fully expose.
Title: Re: Black ink eating through emulsion...
Post by: whitewater on June 11, 2014, 05:01:22 PM
i know 3/3 is overkill...but the screens had streaks when we coated the 2/2

this is a new place we are in, so everytihing climate wise is messed up..I thinkk its the humidity too.