long run discharge

[ericheartsu]

For those of you that have done really long run multi colored discharge jobs, what do you do when you start to get a color shift?

We ran a 900 0202 tultex 4 color (yellow, blue, red, white) print today, and several times we had to stop, clean off all the ink from the screen and add a new batch.

just wondering if there is a better way to do it?

[Underbase37]

Is it starting to dry in the screen? Not allowing some of the pigment to get to the shirt. Or do you think its the activator? destroying the color.

[tonypep]

The best bet is to make large batches of the color and activate and add as needed. We have a library of over 120 DC colors unactivated in the WB ink dept.

[TCT]

So the ink in the screen was shifting color? Is that why you took the ink out? Or was it shifting color because you had to use new batches and they were mixed a hair off?

[ericheartsu]

like Tony was saying, about mixing big batches, when we have big jobs, we always mix two or 3 gallons, and then just activate quarts as needed.

Over the course of the project though, our blues, yellow, and reds got a little less vibrant, so we had to scoop off what was on press, and replace it with freshly activated ink.

Didn't know if other shops had that issue as well

[Colin]

I have only had it on sensitive color shades.  Like gold for example.  Over a few hours the ZFS "can" eat some of the red pigment, making it look more and more yellow.

But other than that.  I have never seen it happen on rich color shades.  Even reds.

Last year we ran 10k+ front and back with the same red shade.  No color issues from first to last.

[Underbase37]

Is it maybe getting hotter than normal? Killing the ZFS ( shorting the activation life ). Maybe flashing? or just hotter in the shop that day. I have seen the red get eaten by the ZFS in cream colors too.

[ericheartsu]

Is it maybe getting hotter than normal? Killing the ZFS ( shorting the activation life ). Maybe flashing? or just hotter in the shop that day. I have seen the red get eaten by the ZFS in cream colors too.

no flash, but heat in the shop is def. an issue.

[ABuffington]

I agree with Tony on this.  Make a master bucket of the color to match.  The key we found was to pre-weigh out the ZFS and put it in small plastic cups with plastic and a rubber band so it wasn't exposed to air.  We had the master bucket and a quart bucket to pull out exactly one quart and then added the preweighed activator.  The other thing we did was to use ink walls to keep the ink localized.  One piece flat over the top of the frame and one piece attached to this and bent down to attach to the screen.  Did this on all 4 sides so the discharge didn't create a thin pool of ink behind the squeegee.  The end walls were moved up to where the stroke movement ended on both ends, but not so close that the squeegee or flood bar would grab it.  Once air gets to a thin layer of ink for an hour or so it loses it's discharge strength.  We focused on keeping the ink at 2/3 of the squeegee blade with a dedicated worker walking the back of the press(es) and adding a fresh drop of ink every 20-30 prints.  Keeping the ink at a good quantity helps.  Don't overdue it so much however that the ink flows back over the design and drips out of the image.  The other crazy trick we tried that still needed a worker watching the back end of the press was to use hand pump dispensers and a long tube down to the activated ink bucket on a shelf we attached to the Challenger's outside supports.  We jury rigged the pump part to be hit by the squeegee carriage as it printed and put a nice drop on the screen to keep ink fresh.  It also helps to push ink to the center to remix and stay fresh, otherwise you can get darker ink color ribbons in the print from ink that is losing it's punch, print immediately to avoid drips.

[tonypep]

That's pretty much what we do. Our ink dept has gotten extremely accurate at knowing how much to make, keep on hand, and activate almost precisely the amount for a given job. Wing floodbars help also