Another newbie question- what's with the pinholes in my ink?

[andyandtobie]

Hey guys, everyone was so helpful with our last problem that I'll ask for help with another one.  I thought I had this problem whipped last time I printed, but it's back: we're getting zillions of pinholes in our prints.  Seems like it's starting in the Matsui Undercoat Binder.  We print the binder, flash for around 25 seconds with a freestanding flash unit, then print the 301W white, and there's pinholes in the white before I even flash it.  Are we getting it too hot?  But it seems like if we flash for less time, we get problems with the following colors sticking to the bottom of the screens.  One thing I am going to do is smear both sides of the screen with softener before starting again, seemed like that made the whole thing easier last time.  Thanks again for the help, you guys are awesome! 

-Andy

[abchung]

I am taking a guess.

You are stroking too fast for the flood and print stroke. Which means you don't give time for the ink to go all the way through the mesh, so when you lay down the ink, you will have air bubbles on the substrate. The heat will make the air bubble expand and burst through the layer of ink.
By putting reducer on the screen, you will make the ink flow easier, thus reducing the chance of getting air bubbles in the ink.

So I think a slower stroke might be the answer.

What we do with 301W is we mix fresh and old one to achieve the right thickness. It is not opaque enough when it is fresh, and it won't go through the screen when it is too old/thick.... We DO NOT add water.

[blue moon]

with plastisol, overflashing will cause that. 'not sure how it relates to water based inks, but I thought I'd throw it out. . .

pierre