understanding squeegee and floodbar pressure

[ebscreen]

You only use diazo and/or dual-cure Tony?

[tonypep]

Yes. We can shoot four auto screens at a clip so the extra time doesn't matter. Will be beta testing the new CCI stuff which is faster.

[ebscreen]

I think diazo has a lot to do with it, but what do I know, I ain't no chemist.


Let us know about the CCI. We'll be making another foray into the diazo world.
The time involved was never a problem in terms of getting screens out, it just drove
me nuts coming from photopolymers.

[alan802]

We've tried the baby powder trick and i've found that it always, just makes even more of a mess, without an added benefit.

I feel like i've been getting great EOM recently, but i still need to buy one of those gauge thingys.

I don't understand why it doesn't help.  It completely prevents the film from sticking to our screens and besides some baby powder on your hand it doesn't make much of a mess.  I wonder what's going on that it wouldn't help your problem.

[ericheartsu]

We've tried the baby powder trick and i've found that it always, just makes even more of a mess, without an added benefit.

I feel like i've been getting great EOM recently, but i still need to buy one of those gauge thingys.

I don't understand why it doesn't help.  It completely prevents the film from sticking to our screens and besides some baby powder on your hand it doesn't make much of a mess.  I wonder what's going on that it wouldn't help your problem.

maybe it's time we hire Alan the Consultant for the afternoon.

[Colin]

The chemistry of the emulsion can have a big factor in film sticking to screens.  I have a CCI emulsion that is terrible on lower meshes ((110-220) and yes, CCI recognizes that this is a problem with that emulsion) that will pull off the ink from my films... even old films.  I am trying out the Murakami AquaSol HV and having none of those issues.  We also have Humidity in the 32%-38% range in our screen room, low 70's for temp.   We are in Beaverton, just outside of Portland.  I have seen this before with outher emulsions....  Hate to say it, but try a different emulsion.  Anything else is a bandaid.

[Gilligan]

if your films are still sticking even after powder you really must have some humidity problems or you are under curing the screen?
just for shirts & giggles get some PAM cooking oil spray, spray it on a towel and wipe down the screen lightly just to see if you get any improvement.
We had real sticking problems with Ulano QTX and waterproof films (all brands) the powder solved the issue 100%.
We throw it on, the powder,  wipe by hand or a towel get a good overall coverage and it always works.
mooseman

I feel like i've dialed in our settings on our exposure unit, i've done a couple of different tests with the calculators to make sure, so i don't think undercure is the issue

I think he was talking about drying your screens thoroughly, but I could be wrong.

[ericheartsu]

if your films are still sticking even after powder you really must have some humidity problems or you are under curing the screen?
just for shirts & giggles get some PAM cooking oil spray, spray it on a towel and wipe down the screen lightly just to see if you get any improvement.
We had real sticking problems with Ulano QTX and waterproof films (all brands) the powder solved the issue 100%.
We throw it on, the powder,  wipe by hand or a towel get a good overall coverage and it always works.
mooseman

I feel like i've dialed in our settings on our exposure unit, i've done a couple of different tests with the calculators to make sure, so i don't think undercure is the issue

I think he was talking about drying your screens thoroughly, but I could be wrong.

most of our screens sit for a minimum of 10 hours before being made. usually its a full 24-36 hours.

[Gilligan]

BTW, I'm sure it's not related as we have the EXACT same issue and we leave ours for at least that long if not longer (slow shop ).

We use Chromaline Blue and even with powder we can have issues, but that's probably due to not enough powder.

Maybe I need to hire this guy:

[alan802]

We've tried the baby powder trick and i've found that it always, just makes even more of a mess, without an added benefit.

I feel like i've been getting great EOM recently, but i still need to buy one of those gauge thingys.

I don't understand why it doesn't help.  It completely prevents the film from sticking to our screens and besides some baby powder on your hand it doesn't make much of a mess.  I wonder what's going on that it wouldn't help your problem.

maybe it's time we hire Alan the Consultant for the afternoon.

Is the Kiwo Discharge a dual cure or full diazo?  I know your humidity levels are higher than ours but even under the most controlled room our pure photopolymer emulsions do this without baby powder.  30% humidity, drying for days, both screens and film and it will rip the ink off if we don't use the powder.  Dual cures don't do this, but I've never tested a pure diazo emulsion so I can't say if it acts like the PP's do.

Seriously though, the baby powder rubbed generously over the screen does not stop the sticking issue?

[IntegrityShirts]

Try a gallon of Aquasol HV, 2/2 coat with the round edge, and adjust your exposure a little for the extra thickness.

No reason you shouldn't be getting a one hit.  Maybe post a video of a flood print for a couple cycles so we can get an idea of speed, pressure, ink slough, etc.

[middletownink]

We had the sticking problem with the textile PV, usually in the summer. Also had the same thing with a CCI red diazo (name slips me now). I would just spray a light coat of clear window frosting over the film. Let it dry for a few min and all was well. We have been using the Kiwo Discharge for a month or so now and no problems with the sticking and I have been rushing screens out of the dry box, shooting them in less the three hours after coating. Maybe it will change once the weather starts getting a little hotter. pGoing to give the quart of WR-14 we got last week a try later this week.

[cvreeland]

I used to have a bad problem with the old Ulano film & ink sticking to the Kiwo Polyplus HWR, but switched to a dye-based ink & film, & it stopped completely. Occasionally, a piece of film will stick a little bit to a screen that's not fully dry, but it no longer pulls the ink off.

We use Chromaline UDC 2 for plastisol, mainly for the fine detail I get with it, & coat it 2/1 dry, then coat again twice on the outside for a smooth finish. On the HWR for discharge, we do a 2/2 with no second coat.

We also keep a dehumidifier running on the screen rom pretty much all the time. As this is Texas, it barely keeps the humidity between 40-50%. I'd prefer that screens dried overnight, but when we're busy, and hour or two is usually fine.