This again.

[ZooCity]

I had to reset a job for my crew that they just couldn't get going.  It's very basic, solid fill, plastisol spot color, about as athletic look as our printing ever gets, literally a shield going on a variety of garments.  All Wilflex, all IMS mixed:

150/48 Underbase Quick White 
Flash (quartz)
Cool/smooth
225/40 Performance blue pms mix *The perf blue covered better. Not uncommon that blues with more body to the ink will cover best. 
180/48 Amazing base mixed National Red
Flash (IR)
Cool
150/48 Hilite Quick White

The issue was one that I see from time to time where the top ink colors have little pock marks of missing ink over the base.  I attached a pic case anyone isn't familiar but I think most on here have experienced this.  Coverage is fine, everything else about the job is great but the pock marks keep popping up intermittently. 

I did my usual routine to dial in the job but spent, as all of my crew did before me, what felt like a silly amount of time dialing the top colors in to prevent this issue.  I've had it dialed thrice now but it keeps coming up, we can't get it rolling steady for very long.

Experience says this is a temp issue.  Too hot/cool on the flash on the UB.   But we have messed with the flash temp endlessly and see the pock marks both when over and under flashing and everything in between.  My guys preheat and we roll steady once going.  It feels like the UB is so finicky that it needs some special magic perfect temp to work. 

All this is based off single stroking all, doing it the "right" way.  We're running 2x strokes on the colors just to get the job out as it avoids the pock marks.

But what causes this? 

I'm starting to think very seriously about finding a new low bleed white that does better as an underbase, I can't help but be suspicious at this point of the ink and I've heard from others that Quick may not be the best for underbasing.  We keep having issues with top colors, with wow printing and otherwise that seem really out of place for how well setup everything is.  Also, Quick on Quick does not display the issue which seems telling to me but then again, it's white ink on white ink so it may just be hiding the issue better.
 

 

[Colin]

Type of shirt?

How dry/moist is the garment?

Do the pock marks go away if you 2 stroke the white base?

You said you ARE smoothing the base white?

[ZooCity]

Gildan 64000 Heather Navy.  Also will run 2200 Navy and 18500 Dark Heather after these.

Yes, smoothing the 1x stroked base at 40-50psi with a roller squeegee and teflon.  Base is printed with 55/90/55 at lighter pressure ≈30psi.  It's strong and with singles all around, 70/90/70 for all others, it's plenty of ink.   

I'd say the garments are fairly dry, it's always pretty dry here but in constant flux as we get bouts of precip most days in the Spring.  About 15-20% humidity in the shop on the hygrometers right now.

I'll try the 2x base but I know the guys have probably already been there and it will be too much ink I fear.

[Screened Gear]

Only time I have ever seen this, it was the underbase was not flashed long enough on the first few prints. Clean your blue screen and your roller. Then start again with hot pallets and flash longer on your first 12 shirts.

[ericheartsu]

we've had this happen a ton too. always had to clear out with 2x strokes

[screenprintguy]

Was just battling this on an 8 color print, 2 of the colors were doing this, changed to 60 duro squeegees on those two and problem solved.

[ebscreen]

We've seen it as well, and usually on thinner/transparent pigment type inks.

2x stroking, softer squeegee, whipping ink through the screen etc will fix it, which makes
you think it's an issue with the top color. Thing is in reality it's likely the base, and it's not
one of the usual base suspects, IE fiber matte down. I think you are on the right track with temp.
Also, I don't readily recall seeing it when we were using StreetFighter.

We have a regular repeat job with big swatches of red (think RUNDMC) where we've taken
to dropping both the underbase and red mesh counts, and using a sixty duro on the red (this in part
due to the chatter we get from to solid lines parallel to the squeegee, but that's another post)
to be able to print in one stroke all around. Obnoxious and a bit heavier than I tend to like but it
gets it done without all the fiddling.

[ZooCity]

Yep, done all that.  None of it solves the issue.  2x stroke on top colors barely gets rid of the pocking, still seeing it.   And now it's introducing a pickup issue printing blue to red wow. 

It doesn't need more ink, it doesn't have an issue clearing, the top inks just won't consistently cover the base in those little pock areas. 

Also, seeing this on a wide variety of testers (damn near running through our supply on this one) so I'm ruling the garment out more/less.

The ultra high print speed helps on the red, been running that one fast from the get-go.  The blue can't hang with the fast stroke though.  Both the top colors need a lot of pressure as well.

[Screened Gear]

You know you maybe right no it only being a Quick white issue. I think I was using quick when was having that issure with a top maroon print. Most of the time when issues like this come up we fix them with changing print speed and pressure.

I just got in a 5 of quick. I haven't used quick all winter. I used extream white and SF for a while. I will have to see if this comes up again.

[DannyGruninger]

We used to have the issue every once in a while.... Several months back we switched away from quick white and I have not seen the issue since. Maybe it was the quick white maybe it wasn't but I've always thought hmmmm to myself that we have not had the issue since. It was always with blue or purple top colors from what I recall. PM me if you want to know what white we are using

[Screened Gear]

Not to take away from this post but has anyone ever had a problem that flashing less solved the issue. I know over flashing can blister the ink or burn the shirt. Is there ever a time that an ink is too flashed...

I have not seen it. I know some say that if you over flash a underbase the top color will not stick. I have never seen that.

[ZooCity]

I can't help but lean toward the Quick.  It's suspect that quick white on quick white or any top color ink that we mixed with quick white in it doesn't do this.

Then again, why is this intermittent? 

Dave pm'd me and got me louping the base.  It has little bitty craters in it.  Some of which appear ink coating inside the crater, like a reverse bubble, some of which don't.  I'm slowing down the stroke on the base to see if it resolves.  If this crater theory holds any water my next test may be trying the IR flash on the base v. the quartz.  I'm thinking the ink could be responding weird (by whatever combination of physical laws) to the quartz wavelengths when using the intensity control and causing the craters.

What I love about this is how dirt simple the print is.  It's always the simple spot color jobs that are somehow the most cryptic. 

[ebscreen]

I have seen issues with overflashing causing issues. Not inter-coat adhesion, but more of a texture issue, the fibers start
to stand up.

FWIW, streetfighter flashes quicker than quick. If we could just get it to stay flooded.

[Screened Gear]

I have seen issues with overflashing causing issues. Not inter-coat adhesion, but more of a texture issue, the fibers start
to stand up.

FWIW, streetfighter flashes quicker than quick. If we could just get it to stay flooded.

I liked SF. The only problem for me is it has too much puff in it. I usually don't have a flood problem with it after 15 or so prints. But I also flood fast. I like to use my flood as a way to keep the ink flowing. I also have my flood bar up off the screen. I like a thick soft fast flood.

[Evo]

Seen this before with Gildans. Maddening, eh? I think it's from the Gildans being not the smoothest knit and the ink not holding an even film on the surface of the fabric and penetrating a bit too much.

The underbase gets cavities in it that the top color can't fill without a ton of pressure or double stroking. Key is to get the smoothest white you can manage. I'd try a slightly sharper angle, slower stroke and as little pressure as possible to clear the screen. Get a nice even ink film. Maybe use less pressure on the roller too.

And maybe grab a better white?