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screen printing => Newbie => Topic started by: OhNoPrinting on March 13, 2024, 03:41:54 PM
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yeah, wanna give discharge ink a second try..
the first set of shirts gave me mixed results. Mainly because i didn´t stir the ink well enough (i guess: i used the same ink a couple hours later and it got much better) and by using scrap shirts.
Now if i want it to discharge more.. (less vintage look) would i use: more of the activator (recommended on pot: 5-10%), try to get more ink onto the shirt or set the dryer temp higher?
*using a pfp didn´t give me better results
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Remind us of what dryer you use. Forced air is a real need with waterbased inks, discharge of not.
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Pics would help pls
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oh, i love to include photos :-)
Dryer is a Workhorse Powerhouse (most likely 2608) Quartz Dryer: (no forced air)
(http://oh-no-printing.de/oh-no-conveyor-belt-dryer-powerhouse.png)
here a B&C E190 (100% cotton/185 g/m²) shirt going into the dryer:
(http://oh-no-printing.de/oh_no_black_discharge_1.jpg)
Early attempt after dryer (on 180 degree C / inside dryer around one minute 20 secs):
(http://oh-no-printing.de/oh_no_black_discharge_2.jpg)
Let the ink soak overnight and try again:
(http://oh-no-printing.de/oh_no_black_discharge_3.jpg)
the red shirt (from H&M) came out really nice:
(http://oh-no-printing.de/oh_no_red_discharge_1.jpg)
but a day later, had some discoloration appear:
(http://oh-no-printing.de/oh_no_red_discharge_2.jpg)
So, how do I always get really clean (less vintage) prints: I probably need to stir the ink better, but.. is there another trick? heat? activator? (i am cheap so i guess i used 5% instead of 10%)? Using a lighter shirt?
ps: my favorite shirt out of that session is by the way a poloshirt -> that really looked cool with discharge
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6% activator is standard. With red ink try 3%.
regular temperature as the plastisol, but much, much longer times. You have to actually dry the ink (unlike plastisol which has a chemical reaction and is almost instant once the temperature is reached) so all the water evaporates. This could be several minutes in the dryer.
few thoughts:
-once activated ink has a limited shelf life and will generally not discharge as well later on. In some cases you can add more powder and reactivate. You'll have to do your own testing to find out.
-shirts should go through the dryer in one pass. might have to run the belt at lowest speed possible.
-shirts have to be discharge compatible. For the most part that would be 100% cotton. Some blends work, but not many. Shirts have to be dyed with a reactive dye. You can mix some powder with water and dab the shirt on the inside of the seam. You'll be able to tell how well it works without ruining the shirt.
-some colors work better than others. look for a discharge compatibility/performance chart from Gildan and Anvil. In general purple and royal don't work. Reds tend to be tough. Your best bet is to look at the charts and then order few shirts and do the testing. Once you find stuff that works stick with it.
-even the shirts that work will have issues. There might be more dye in one lot than other. They could be made in different countries and so on. Your size Large might print different than Medium. This will not happen often, but it will. and you most likely just ruined some shirts.
-re-dyes don't work. Manufacturers might make a ton of Kelley green for st patrick's day and if they don't sell they are stuck with them. They will dye them black in order to move them, but re-dyes don't discharge well. So a safe color like black might not work. Make sure you specify when ordering that you shirts are for discharge. This should prevent getting re-dyes.
We have several ppl here that are very good with discharge and they could help more. My observations are few years old, but I would imagine they still are valid.
pj
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What Pierre said. Also, you want the ink to be driven into the shirt.
Technique and additives (penetrant etc and/or water depending) will help.
I always had a difficult time getting good saturation when printing wb manually.
Need to eat more Wheaties.
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I always had a difficult time getting good saturation when printing wb manually.
Need to eat more Wheaties.
High tension screen. Get the open area as wide open as possible. Low off contact. Shear a thin flood forward then drive the ink in there on the print stroke.
It helps if you weigh north of 200 lbs lol.
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On the subject of manual printing.
Are you a puller or a pusher?
I pulled for fifteen or more years before I became a push convert. Really helped clear the screen.
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Pusher, but I did quickly notice that the better manual printers have some gravity behind them.
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On the subject of manual printing.
Are you a puller or a pusher?
I pulled for fifteen or more years before I became a push convert. Really helped clear the screen.
I pull print. Generously thin the ink (keep it wet!) and do a push flood, NEVER a pull flood unless you are walking away from the press for a minute. Sharp angle. Shear the ink to a very thin layer, just enough to fill the image at EOM thickness. Keep your screens tight and off contact as low as possible. Print strokes are WAY easier this way and the screen clears completely.
With thick floods you are fighting a pile of ink on the print stroke and risking smeared details.
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I pushed for a long time but for some reason whenever I get on the manual now I pull stroke can't tell you why...@ Evo, never thought about it way of fighting a thick flood of ink, really makes sense now that I think a bout it....Thanks
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Nobody's said the main issue, you aren't curing long enough. 80 seconds on a small electric dryer isn't enough time to evaporate all the moisture from the print.
Also discharge just doesn't work like it used to, not sure what changed but basically ink manufacturer wide discharge just isn't as bright white anymore in my opinion.
Discharge under base, and high solid whites if you want a consistent soft, white print. Add in all the variables of different tees being hit or miss, it's the safer bet.
But you aren't curing long enough, and I would make sure you really drive the ink into the garment.
That dryer should be on turtle mode.
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That dryer should be on turtle mode.
Agreed. And even with that, not really enough uninterrupted tunnel time. Turtle mode to make it activate, and maybe a fixer additive to insure the colors remain somewhat washfast.
And/or send them all through again to heat set.
Also - Test test test. Put em in the washer on harsh settings (with Tide).
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thanks for the great tips..
-> Main take-away: finally! being over 90kg is a plus
-> i pull most of the time because of squeegee durometer, but admit, after trying pulling white plastisol, i pushed it. (learned quickly not to combine these two)
-> i am shocked that discharge is waterbase.. i really thought its a kind of plastisol. reading the label helps.
-> after reading the label: this discharge ink is Formaldehyd-free.. it still stinks toxic ;-) maybe that is the difference?*
*in my limited-understading.. Zinc-Formaldehyde-Sulfoxylate (ZFS) was the active ingredient, now its Aminoiminomethansulfinsäure (Thiourea Dioxide)
-> with the dryer i am stuck, but maybe i try to: pre-flash to get the moisture out, print (low mesh, lots of ink), let it go through the tunnel two times.
:what i discharged stayed the same in the washing, only the red shirt changed its appearance the next morning
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thanks for the great tips..
-> Main take-away: finally! being over 90kg is a plus
-> i pull most of the time because of squeegee durometer, but admit, after trying pulling white plastisol, i pushed it. (learned quickly not to combine these two)
-> i am shocked that discharge is waterbase.. i really thought its a kind of plastisol. reading the label helps.
-> after reading the label: this discharge ink is Formaldehyd-free.. it still stinks toxic ;-) maybe that is the difference?*
*in my limited-understading.. Zinc-Formaldehyde-Sulfoxylate (ZFS) was the active ingredient, now its Aminoiminomethansulfinsäure (Thiourea Dioxide)
-> with the dryer i am stuck, but maybe i try to: pre-flash to get the moisture out, print (low mesh, lots of ink), let it go through the tunnel two times.
:what i discharged stayed the same in the washing, only the red shirt changed its appearance the next morning
We tried the non-ZSF discharge from Magna many years ago. It didn`t work as well as the ZSF discharge inks. At least back then, maybe they have changed the formula now but try using ZSF discharge and see if you notice a difference.
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so.. gave it another try. Mixed results again.
Look at this photo:
(http://oh-no-printing.de/oh_no_discharge_again.png)
Now the bummer is:
the right one I printed with discharge ink after i mixed the ink and left it for 2 hours to rest. I took it from the pallet directly to the conveyor dryer for 3 runs each 1.20 minute / 160 degree C. Came out super vintagey.
The left one I did a day later with the same ink still in the same screen. Same shirt brand. But this time: i flashed it three time for each 3 seconds and ... voilá: white.
I guess I will contact the seller of the ink and ask for advice on how long the ink should "rest" and if this is a bug or feature :-)
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so.. gave it another try. Mixed results again.
Look at this photo:
([url]http://oh-no-printing.de/oh_no_discharge_again.png[/url])
Now the bummer is:
the right one I printed with discharge ink after i mixed the ink and left it for 2 hours to rest. I took it from the pallet directly to the conveyor dryer for 3 runs each 1.20 minute / 160 degree C. Came out super vintagey.
The left one I did a day later with the same ink still in the same screen. Same shirt brand. But this time: i flashed it three time for each 3 seconds and ... voilá: white.
I guess I will contact the seller of the ink and ask for advice on how long the ink should "rest" and if this is a bug or feature :-)
What ink are you using?
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Its (probably) rebranded discharge ink with white pigments mixed into - activator includes Aminoiminomethansulfinsäure but is Formaldehyd-free.
I send an eMail to the supplier to ask what I can check.
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Its (probably) rebranded discharge ink with white pigments mixed into - activator includes Aminoiminomethansulfinsäure but is Formaldehyd-free.
I send an eMail to the supplier to ask what I can check.
My initial thoughts are. Sending it through the dryer 3 times is very different from curing it once at the right speed and temperature. Each time you send it through the ink and the activator need to reach the full temperature first before any further reaction takes place. Magna non-formaldehyde discharge needs to cure for 2.5 - 3 Minutes at 170 degree Celsius. On top of that non formaldehyde discharge whites are generally less bright than classic discharge whites. I assume you don`t have a dryer with good airflow, right?
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you are totally right that sending the shirts multiple times through the tunnel is less than ideal. but i will do one more test, where i mix the ink, let it sit for 12 hours /print+tunnel/ and then see if i get the left result which is more than ok in terms of brightness. Its just the waiting time of the ink which makes me wonder if i miss something else. (Like with waterbased white: tried to follow the manual, but.. cracking, so clearly my process is not optimized :-)
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Not much help here perhaps but, when working with the (now discontinued) Rutland ZFS systems extensively all day every day, we actually activated the inks immediately before printing. No flashing and down the gas dryer 330 degrees normal retention time with no issues for many years.
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you are totally right that sending the shirts multiple times through the tunnel is less than ideal. but i will do one more test, where i mix the ink, let it sit for 12 hours /print+tunnel/ and then see if i get the left result which is more than ok in terms of brightness. Its just the waiting time of the ink which makes me wonder if i miss something else. (Like with waterbased white: tried to follow the manual, but.. cracking, so clearly my process is not optimized :-)
I can`t really imagine that letting the ink sit for longer will get you a better result. In many cases the inks won`t discharge very well at all after 8 hours. can I get a link to the product page? Same for the waterbase white.