What causes Discharge ink to fade on a shirt?

[ABuffington]

We found that after producing matching color in the prints that after the first wash they lose some punch.  The problem was not the ink, it was back dyeing from the shirt color.  Black is epecially prone to releasing excess fabric dye that will color the print.  You can pre-wash the shirt, but then other issues of shrinkage, wrinkles and all that labor didn't make any sense.  We eventually went to making our own shirts with local cut and sew and dye houses who fixed the dye better, not cheap.

The cure is also key.  Gas fired hot air 20' with electric in and out has all the controls you need to dial in any combination of cure for the discharge, puff, or specialty inks.  Forced air is much more gentle on the fabric as well.  All electrics can burn the shirt.  Try pulling a black shirt sideways to see if it splits down the middle, this can happen on inexpensive open end shirts that get more radiant heat than is needed to cure the discharge.  Hot forced air and belt speed with a long tunnel helps to keep production up and labor costs down.  We had electric in and out.  This is hard to come by today, but the advantage is you can get plastisol/gels/puffs/adhesives up to temp quick and then all gas forced air that follows can finish the plastisol/specialty ink cure as it is bringing the discharge up to a steaming temp to do it's work. ( Once you have evaporated the water portion of the ink it may not hit the color on the second pass since it can't steam properly to get the disharge process to work.)  For specialty inks the electric out can be handy to finish puffs, gels or hd.

For foiling we put on an oven extension with heat presses next to the belt to apply foil to hot gels or foil adhesives.  At this point it only takes <5 seconds to marry the foil.  One recipe to try is 110 puff ink/light flash to dry but not puff using quartz flash followed by 60 mesh w foil adhesive (IC).  This will work wonders on keylines to give a 3d textured puff foil, (our #1 embellishment for Disney).  We foiled as they came out of the oven, with the key feature to run them through the oven a second time to raise the Wilflex puff underneath the foil giving it a gold nugget look (Textured line work or rough line work helps.  Avoid solid areas with this technique.  A 1-2mm line weight works well with a coarse mezzotint.  These jobs often had 6-8 colors of discharge as well.  The discharge was the easy part with 20' gas ovens, the shorter oven we had never had consistency to do top shelf production.

[ericheartsu]

The Heatwave is a gas dryer with convection air, not sure what to do if you have an electric dryer, I know if there isn't airflow you are kinda skating up a hill. With a gas dryer, I haven't seen a shirt, even poly "burn". Now shrinkage, there are some shirts that it's almost impossible to avoid that, like tri blends, freakin hate them especially when people want water based inks. For that, Green Galaxy makes some awesome inks that you can add their "warp drive" to, and cure them very fast at below 300 degrees. 340 "shouldn't cause a lot of shrinkage" if you temp test and see that your print is hovering at that 330-350 mark, if it rises up then you will probably see some shrinkage. We just ran a big batch of bellas and canvas, it was really humid today so we had the heat up in the dryer to 360, same speed, everything was nice. Dryer day I would have brought the heat down to 340. Really the battle is the time in the dryer. I only have 8 feet of heat in the Heatwave so it's not, "ideal" for w/b printing, you really want 12' for more, but I know that's not always an easy run to the store and buy a bigger dryer, so we just slooooowwwwwwwwwwwwww down, which sucks, but it's better than 500 fashion fit shirts with multi location printing coming back because the ink is washing out. That new Sprint 3000 is built with the WB printer in mind. When we were up at the plant for the tour we were shown how the design lends itself to forcing more of the hot air down and through the shirts to get the ideal cure of waterbased/discharge, and HSA inks, nice machine for sure, but until any of can get into one of those, slowing things down is the cure I guess.

yeah the bella/canvas triblends were what i was thinking about, as we've had some issues with those. Right now we are running our sprint international at about 360, but at the slowest speed i can get, i'm still only getting 1min 30. I need to tweak it a little more to allow it to go a bit slower.

[ZooCity]

You're absolutely right screenprintguy, it takes a way bigger/badder dryer than you might think to do this efficiently.  When we were lining up dryer everyone, myself included thought the Sprint High Output was going to be overkill but I am very, very glad that is what we ended up with.  Even at 16' of chamber and all that airflow and btu it still just keeps up with two presses running wb/dc/hsa.  I'd second Alan's 20' chamber suggestion, sounds just about right from our experience.   If that length won't fit I'd look at 72" belt v 60" then. 

I didn't know there was a change in circulation with the Sprint 3000, that's interesting and also good to hear.  What did they modify?  My guess is the air knives where re-designed?

[Rob Coleman]

Just a quick note to all who replied here:  good stuff and thanks!  There is some great information here than can be used as a resource. 

A couple of quick comments -- These were covered by others; but I think they are important! 

Yes the discharge process can happen before the ink is "cured" (read: water evacuated). 

You also do not want to start the discharge process, stop, and then restart (read: run through dryer multiple times).  You can easily get significant color variability.

As far as binder percentage by the manufacturer -- agree 100%.  Sometimes there is a reason that a product is much lower costing.  Same with the pigments.  You are limited if these are on the weak side.

All in all - good advice here in this thread!

[screenprintguy]

You're absolutely right screenprintguy, it takes a way bigger/badder dryer than you might think to do this efficiently.  When we were lining up dryer everyone, myself included thought the Sprint High Output was going to be overkill but I am very, very glad that is what we ended up with.  Even at 16' of chamber and all that airflow and btu it still just keeps up with two presses running wb/dc/hsa.  I'd second Alan's 20' chamber suggestion, sounds just about right from our experience.   If that length won't fit I'd look at 72" belt v 60" then. 

I didn't know there was a change in circulation with the Sprint 3000, that's interesting and also good to hear.  What did they modify?  My guess is the air knives where re-designed?

From what I understood in conversation with Rich Hoffman was that the Sprint 2000's burner was good up to 16' of chamber, and the new 3,000's burner was good up to 20' of chamber and something to do with a higher velocity blower and the air knives, "I think" allow more flow from the 2,000. At the plant Dave Zimmer had said a ton of thought in the 3,000 came from all of the R&D that they had been doing with HSA inks for different big clothing lines, like Nike as well as the ink Manufacturers themselves. I would assume the new design is to allow printers to still have a high output using waterbased inks like they can have with plastisol. I can only imagine a printer needing to run water based prints at 100 dozen an hour or more would need a dryer that gets the job done properly. Also the 3000's has new controls among a ton of other things so instead of setting a speed you program recipes so that an operator can easily re-load a preset for the desired temp and dwell time, pretty cool stuff. I think there are sensors in there that measure substrate temps as well. 244 will probably chime in on more specifics but the one we saw at the plant, even with the big side panel open was quiet, cool and a serious looking machine for sure.

[ABuffington]

The dryer is the biggest issue with production, especially if you feed more than one auto printing wb and discharge through the same tunnel.  2 large wb/discharge prints in the same oven requires even slower times as the water evaporation loads up the humidity levels and affects curing.  Our Electric in and out with 20' of 2 gas burners for each 10 foot section maxed out with 2 presses. (although we printed night shirts and beach wear with huge prints, smaller prints would be easier to cure). If you load up the 60" wide belt with three presses of printing wb the curing was often marginal, requiring presses to slow down to avoid loading the belt with so many shirts that returning hot air was blocked by all the shirts.   This reduced air flow trapped humidity in the oven chamber.  Having some space between shirts helps air circulation.  A short tunnel or too many wb presses feeding the oven makes it hard to get consistent discharge affect.  We often put a quartz flash in the last head to get the process started so the oven did not have do all the work to get the ink/shirt up to temp w/ just hot air.  A good flash before the oven also helps spot pinholes much sooner than having the catcher find them.  Change filters or wash out permanent filters weekly, or daily depending on 24/7 production.  Air circulation is the magic bullet to cure.  Oven maintenance of air flow, cleaning out all dust build up including jets, new air filters, watch for pellons blocking air exhausts, check air exhaust for large clumps of shirt fibre.  We did this monthly, as all surfaces need to be free of dust build up and especially blocked airways or exhausts.

[ABuffington]

Feel free to PM on matching color with discharge.  PMS color is always a ball park match, consistent color matching within a design is possible, guaranteed PMS color matching is not due to so many factors.

[ebscreen]

Just wanted to commend Mr. Buffington on providing a great example of a manufacturer/rep. sharing valuable information
and experience on our beloved printing process. He has something to sell, but he's not trying to sell it to us. Hell, the subject
at hand has little/nothing to do with the products he manufactures! Other companies take note, this is how you do it!

(doesn't hurt that the products they make are top-notch to boot)