Printing Matsui waterbase on cardboard

[Alchemink]

It works and it looks great. I've done it once before (manually) for some in-house boxes to send samples in. 2 colors: red text/black background. I washed those screens out when I was done a couple months ago and they looked okay. I pulled them out to re-print those boxes and tried it again (also manually). I ran into an issue where after I printed the red, I'd print the black just like I did last time and the red would just bleed like CRAZY. It was like as I printed the black the red got smushed.
I got a few good ones to tide us over but over half of them were crap. I tried altering the off-contact both more and less...

This industry always seems like there is an exponential amount of variables that could be causing any problem so maybe some input from you fine people will help me narrow it down.

Other than too heavy of a deposit of red, what other variable could cause this? I'm stumped.

Going to try this again tomorrow with a sharper/harder squeegee for the red for a reduced deposit.

The box is regular cardboard that is brown on the interior and white on the exterior when assembled. I'm printing on the white side obviously.

[Frog]

Pictures of both the former good and present bad could only help

[Alchemink]

Looks like the black wasn't as good either... I'm starting with brand new screens today so....fingers crossed

 

 

[Frog]

Have you examined the screens for deterioration with a loupe or other magnifying device? (I see that you are already leaning in that direction for the next try)
Are you using an emulsion that is known to be good with wb ink?

[Alchemink]

I'm pretty much 100% sure there's nothing wrong with the screens. I tried it again and it did the same thing...

In my formulations of ink that I make, I use 3% of Matsui Retarder to help prevent my ink drying up and clogging my screen. I have noticed that this retarder has an oily texture to it, which would make sense if we're trying to keep the ink 'moist'.

My theory is: somehow, someway, I did NOT use retarder the first time I tried the boxes and that's why I shouldn't have used it this last time. I believe my ink was bleeding this last time not only because was the ink deposit fairly excessive (very open, solid text through a 156 mesh), but there was also an additive added to the ink making it more viscous, moist and prone to spread/bleed when pressure was applied to the second color screen.

I don't think it was necessary to add the retarder to ink that was being pushed through such a moderately low mesh, especially if I had enough ink in the screen.

So.....how did I fix this?

I just threw some red plastisol in there and powered through it. The plastisol added a kind of gloss to the red also which was a nice touch. It also did NOT bleed barely at all.

I hope to revisit this problem in the future and give an update on the results.

[Admiral]

I would look into higher mesh count or more of a gasket on the stencil.

[ericheartsu]

yeah id think a higher mesh count would help, or maybe switching to a WB that's meant for paper? something like speedball or TW?

[Frog]

Of course, it's still a mystery why it was so much nicer the first time (with the same screens)

[RICK STEFANICK]

It is too much deposit on the red printing on a box. try printing black/red or bump up to 230 mesh on both colors. also a minimum of a 70d squeegie. You also have to have off contact