[SixFootSouthern]

Dear TShirt Forum,

We have been in business for about a year now and have mostly settled down to a routine. I am still not happy with that routine and I am now beginning to perfect our printing process.

Background info:
Textil PHU 1/0 Coating Thin Side on Coater
Normally Use 150ish Screens
Permaset Inks Supercover and regular
Ryonet Printing Press 4/4
Ryonets 24X38? exposure unit
Coated screens are allowed to dry overnight
Exposed for around a minute and a half
Printing in our garage 60% Humidity 80-86 F generally on the hotter side
Live in Fl
Conveyor Dryer and a flash dryer


Printing Process:
No clearance from t-shirt to screen
Print around a 75 degree angle medium pressure(Been playing around with this)
Lift Screen
Drop Screen
Print again
Flash or final dry
Just did a white on black shirt had to be repeated twice

Errors that are occurring:
1)Coverage on shirt is uneven when printing ie areas are more opaque than others
2)Ink sometimes gets under the screen leading to a wasted shirt
3)Ink consistency changes quite rapidly.
4)I don't think 4 prints should be necessary to get decent coverage. Notice decent not perfect.
5)Ink gets super thick and I end up putting it back in the container and grabbing fresh. I know a water spray bottle helps this.

We generally burn about 1-2 shirts on a 50 shirt job but every once in awhile one will bloom to like 5-8. Not a good error rate especially when they are bringing the shirts. I'd like to eliminate this margin of error completely.

I'm looking to getting around to watching someone print locally around here to learn more but I'd love to get some online feedback as well on where I can improve. I won't allow anyone else to print(I have two other individuals who can) until I feel confident enough that my results can be repeated again and again.

I'm sure i'll think of more. I am just now fixing up our screen coating and exposure process(looking for that perfect screen!) but looking forward to hearing some suggestions. I have done a ton of research, including using this forum which got me to printing at a beginner level, but I am missing something imperative to this very intricate process.

Thanks,

Steven

 

[DrivingZiggy]

Steven! I'm a rank beginner. But when you say:

No clearance from t-shirt to screen

It tells me that you are not using "off contact." Even though I've never screen printed, it seems like everybody who does places a lot of emphasis on setting the off contact correctly.

 

[SixFootSouthern]

You are correct. Waterbased printing is a little different than Plastisol though and will generally require zero to very little off contact. The inks are very viscous

 

[NoXid]

I use the same emulsion and ink, and started out with a Ryonet Silver press

With the Silver, 0 off contact helped to keep the pitch/angle adjustment from changing mid-job. But if you can keep that from happening, you might like about an 1/8" off contact--I do now that I have a better press. It might help with the ink smushing out past the design.

I started with 156 screens and had a hard time getting good prints--not enough ink in some places, too much in others. Part of that last issue was me not clearing the screen well enough with my stroke.

After your wet stroke, do a dry stroke to make sure all ink is cleared from the mesh. Else when you lift the screen some of the residual ink gets sucked out onto the shirt and makes some areas thicker and rougher. Flood and do the above again. Then flash.

Then single wet stroke and flash as needed until the desired opacity is reached. I use 200 mesh, so typically it takes two rounds of this to get a nice bright white print on black.

On some fabrics, like tri-blends with Spandex, I have to do one or two of those strokes on the hard side in order to get even coverage with some designs. You don't want to go real hard on the strokes before the first flash or you can drive ink all the way through the fabric.

All that said. Do you have any unmolested fresh ink that has never been in a screen? I keep my working ink separate from my fresh supply so I can always compare them to see how much moisture the working ink has lost. Misting ink while printing is not enough. You need to refresh used ink when putting it back in a can and/or when getting ready to print. A lot of moisture is lost to screen emulsion and the air. If a big blob of Permaset Supercover white won't mostly slide off a metal spatula, it is too dry. If it is climbing up your squeegee, it is too dry. If your prints are rough and not covering evenly, it is probably too dry. PorkChopHarry tried to convince me of this, but I did not believe the extent to which the ink needed replenishing with water until I bought a new bucket and saw just how much wetter the fresh ink was than the sludge I had been working to death.

Properly wet ink solved more of my printing problems than anything else.
Wet/Dry/Wet/Dry/Flash as a base on which to print subsequent layers made my prints more consistent.

 

[SixFootSouthern]

Sorry I may have a few questions and such about what you are saying. I want to fully understand the process.

With the Silver, 0 off contact helped to keep the pitch/angle adjustment from changing mid-job. But if you can keep that from happening, you might like about an 1/8" off contact--I do now that I have a better press. It might help with the ink smushing out past the design.

With an off contact like that what prevent the smushing? Or a better question what causes smushing? Too much pressure on the squeegee ?

After your wet stroke, do a dry stroke to make sure all ink is cleared from the mesh. Else when you lift the screen some of the residual ink gets sucked out onto the shirt and makes some areas thicker and rougher. Flood and do the above again. Then flash.

I'm arriving at the same conclusion and actually did the exact process you described with a lift in between the 1 and 2nd flood/dry combo yesterday.

Then single wet stroke and flash as needed until the desired opacity is reached. I use 200 mesh, so typically it takes two rounds of this to get a nice bright white print on black.

Looking at quite a bit of time as I discovered yesterday completing this print flash process. Anyway to speed this up?

On some fabrics, like tri-blends with Spandex, I have to do one or two of those strokes on the hard side in order to get even coverage with some designs. You don't want to go real hard on the strokes before the first flash or you can drive ink all the way through the fabric.

These hard strokes are where I worry about the smushing occuring.

You need to refresh used ink when putting it back in a can and/or when getting ready to print. A lot of moisture is lost to screen emulsion and the air. If a big blob of Permaset Supercover white won't mostly slide off a metal spatula, it is too dry. If it is climbing up your squeegee, it is too dry. If your prints are rough and not covering evenly, it is probably too dry. PorkChopHarry tried to convince me of this, but I did not believe the extent to which the ink needed replenishing with water until I bought a new bucket and saw just how much wetter the fresh ink was than the sludge I had been working to death.

This process has been implemented in the past few months but during the printing process you definitely see the change and it becomes a dry hot mess. Basically what I do is take the old ink off put it back in, refresh, put new ink on. That being said during this process the screen could potentially dry in a bit.

Properly wet ink solved more of my printing problems than anything else.
Wet/Dry/Wet/Dry/Flash as a base on which to print subsequent layers made my prints more consistent.

I'll be keeping a more watchful eye on this from here on out to see what else I can do to keep the ink silky.

 

[NoXid]

Smushing might be too hard of a flood stroke, too thick of a stencil (good for Plastisol, bad for WB) but you did a thin stencil so it's not that, or? Not sure. Perhaps someone with more experience printing longer runs will chime in. Perhaps every X-number of shirts you'll need to do a dry stroke on some scrap and wipe the back of the screen to prevent smushing some shirts.

 

[socceronly]

Should you flood on the shirt or off of it?

I have seen people do it both ways, even the both ways in the same video.

Someone suggested flooding with the screen up help prevent fibrillation.

 

[SixFootSouthern]

Smushing might be too hard of a flood stroke, too thick of a stencil (good for Plastisol, bad for WB) but you did a thin stencil so it's not that, or? Not sure. Perhaps someone with more experience printing longer runs will chime in. Perhaps every X-number of shirts you'll need to do a dry stroke on some scrap and wipe the back of the screen to prevent smushing some shirts.

Sorry for the late reply we had a large order and then I ended up forgetting all about this.

Got test out a bunch of different methods to figure this out.

I am now a hundred percent on the keeping inks at the correct water content train as you really see a difference. Your stroke method also worked out really well for me.

My largest issue is how often I need to keep the ink "nice" i'll literally rotate out all the ink and put fresh ink on every 7-8 shirts sometimes sooner. I'd like to hear how often everyone is doing this.

My largest issue(certainly not my last) is the Permaset white. It dries in the screen so fast. I'm using 200 mesh for all my colors and the other colors do not have these issues at all. I'm easily able to catch them before the dry in starts but with white it was literally drying in the screen before I got the third shirt done. Lower mesh count? But then i'm looking at not being able to do high detail whites on darker shirts.

I'm also still floating with a fairly high waste percentage. I'd say around 6%-10% is my average currently and it is pretty much always due to the ink in some fashion or another.

That smushing appeared again with the white. I think I put too much water which caused it to bleed easily. But then it dries so quickly so it seems like a real catch 22 there.

 

[NoXid]

Sorry for the late reply we had a large order and then I ended up forgetting all about this.

Got test out a bunch of different methods to figure this out.

I am now a hundred percent on the keeping inks at the correct water content train as you really see a difference. Your stroke method also worked out really well for me.

My largest issue is how often I need to keep the ink "nice" i'll literally rotate out all the ink and put fresh ink on every 7-8 shirts sometimes sooner. I'd like to hear how often everyone is doing this.

My largest issue(certainly not my last) is the Permaset white. It dries in the screen so fast. I'm using 200 mesh for all my colors and the other colors do not have these issues at all. I'm easily able to catch them before the dry in starts but with white it was literally drying in the screen before I got the third shirt done. Lower mesh count? But then i'm looking at not being able to do high detail whites on darker shirts.

I'm also still floating with a fairly high waste percentage. I'd say around 6%-10% is my average currently and it is pretty much always due to the ink in some fashion or another.

That smushing appeared again with the white. I think I put too much water which caused it to bleed easily. But then it dries so quickly so it seems like a real catch 22 there.

Are you in a dry climate? I'm in Portland, Oregon, so the air is generally not very dry. I have a small, cheap humidistat from Home Depot, and if the humidity is below 60% in the shop, I spray some high pressure water around in the washout booth and that pops the humidity level up a bit. But if you are in Arizona, or the like, you may be better off with a humidifier (of course, then you need a separate dry environment for drying screens).

I think it is the high, high pigment load that makes the white the worst for drying out quickly. I wipe the emulsion (not the image area) down with a damp cloth before loading the screen with ink. Even then, white ink residue gradually builds up on the emulsion around the edges of the screen. But that doesn't really hurt anything.

As I mentioned, @porkchopharry is who pushed me in the right direction on this. He lives in southern CA and it gets hot. He starts by wiping the screen down with water, and with properly wet ink, and then mists the ink from time to time as he is working. He has printed some decent sized runs this way and has had to clear the occasional clog, but I don't remember him mentioning smushing as a problem. He prints mostly with 180 mesh, and he prints hard. I've have some of his work; it is nice and crisp. He seldom appears on here anymore, but you might look at some of his old posts.

Hmmm... speaking of PorkChopHarry does remind me of how many times he mentioned, in one way or another, that he prints hard. With Plastisol, one is shearing the ink off to create a layer on the surface of the fabric. With WB, one is pushing the ink into the fabric. If one deposited too much wet WB on top of the fabric, it would no doubt smush around. Maybe experiment with harder print strokes on some scrap?


I know I have seen some sort of article that mentioned the smushing problem, but I'm sure it was particular to Plastisol (as so much older information on printing is). Plastisol does not want to go into the fabric, so it would smush out onto the back of the emulsion if too much ink got put down. There might be a clue in there somewhere, not sure.

 

[porkchopharry]

Sorry for the late reply we had a large order and then I ended up forgetting all about this.

Got test out a bunch of different methods to figure this out.

I am now a hundred percent on the keeping inks at the correct water content train as you really see a difference. Your stroke method also worked out really well for me.

My largest issue is how often I need to keep the ink "nice" i'll literally rotate out all the ink and put fresh ink on every 7-8 shirts sometimes sooner. I'd like to hear how often everyone is doing this.

My largest issue(certainly not my last) is the Permaset white. It dries in the screen so fast. I'm using 200 mesh for all my colors and the other colors do not have these issues at all. I'm easily able to catch them before the dry in starts but with white it was literally drying in the screen before I got the third shirt done. Lower mesh count? But then i'm looking at not being able to do high detail whites on darker shirts.

I'm also still floating with a fairly high waste percentage. I'd say around 6%-10% is my average currently and it is pretty much always due to the ink in some fashion or another.

That smushing appeared again with the white. I think I put too much water which caused it to bleed easily. But then it dries so quickly so it seems like a real catch 22 there.

Are you still having these issues? If so...

Mesh - Why are you only using 200 mesh? In hot climates; you are begging for clogs - especially with SC White. I have printed SC in my shop when it is 120+ degrees and it can be a hair pulling experience.

Even on my 180 screens with ANY SC color, I have to redo the screen on an average of once a year. As the edges of the stencils begin to clog inwards. Especially on fine details and/or font designs.

Bear in mind that I do not do custom jobs. Only my own stuff - so some of these screens see repeated, repeated abuse. I'm certain that you could drop to a 160 on many of the screens and be just fine. Unless you are doing uber detailed and or halftones all the time.

Smushing - Adjust off contact HIGHER and stop panicking. Make sure there is enough tack on the platens. Work FASTER, should be no need to wipe down the screen if you are continually stroking the mesh with the squeegee.

Uneven prints - warped frames? It's been a long time since I used a silver press, but sounds like either your off contact is not even. Or you are not stroking evenly.

Ink drying in the buckets - leave about an 1/8" layer of water on top of the ink when you are done and let it sit overnight.

Ink drying IN the screen - mist lightly IF you have to, and keep the ink moving in the screen.

Smudges, etc - you can flood pretty hard I find. Like REALLY hard with no smudges/blotches. But if you are misting - mist from afar and mist gently. If you are not misting and getting smudges, then you may not be mixing the ink well enough before putting it in the screen.