Coating Question

[ScreenPrinter123]

Gilligan and Printficient,

This was recently a discussion I had with someone at my office - about just flipping or turning the screen to the other side -- I kinda sided with Printficient because of a video I saw (maybe it's the one posted here recently on coating) -- but lately, we've just been going the path of least resistance, hoping Giligan is right and that it makes no difference.  Has anyone tried both methods with the same amount of coats and noticed any difference in printing opacity?

Secondly, is there a point at which I should just give up on trying to achieve halftones with coating many times?  I'm going to give a go on 7/7 tomorrow on a 150 s mesh (w/chromablue) because quite frankly I thought a 4/2 -- which someone recommended and which I tried today -- didn't end up creating all that great of a thick stencil - perhaps I'm pursuing a lost cause at trying to get a popping white on a first hit?  At any rate, a lot of the halftones shot out on the 4/2, but definitely not all.  So I am wondering if it gets to a point that the thicker you go with the EOM, the less likely the halftones will shoot out?  Assuming you have your exposure unit dialed in perfectly, I am wondering if the halftones would blow out by the time you were able to remove all the layers of emulsion on the stencil?  With the 4/2 the halftones didn't "melt" out like with the thinner EOM -- I had to work at them and then it was either stop and let some of them remain closed or start blowing out the ones that were already shot out correctly if I continued on shooting out the screen.  Anyone?  Beuller?

Thanks.

Take everything you said here and dont do it anymore. That will be the start of fixing your problems. You are doing way too many passes on those screens. Unless your trying to stop a bullet you do not need emulsion to be that thick.

What screen mesh are you using to try and get halftones to wash out?

LOL.  Experimenting always sounds dumb at first, I guess - but I guess I'm just a newb at the end of the day.  I was able to shoot out decent halftones with a 2/2 on a 150 s mesh, but going lower than that mesh count was not happening with the halftones, nor was I expecting it to.  I, like some others, am just trying to create a thicker stencil to see what significant difference, if any, a 2/2 has over a 1/1, a 4/2 has over a 2/2, and tomorrow, a 7/7 over a 4/2 .  If I don't see a glaring difference, I'll stop spinning my wheels -- by difference, I mean how much more pop a white print would have on a dark color shirt.  If there exists no dramatic difference, then 1/1 and 2/2 work just fine for me.

[JBLUE]

There is no real wrong answer when coating your screen. Some people need a thick stencil and some do not need one. It all depends on how you print. For us we don't ever go below a 140 coated 2/2. That's on the low end. We stay mostly in the neighborhood of 160-180-230 coated 2/1 and 2/2 for our underprints. It's  all about the stroke, pressure, speed, off contact, flash time, smoothing screen, ink type, additives (reducers and soft hand), mixing before printing, ect. Emulsion thickness is a small part of it. What you want is emulsion consistency. We have had Kiwo, Murikami, and CCI all check our screens and they are consistant with the proper EOM. What it boils down to is your technique. It takes practice to get good consistant coating down.

Are you using the sharp edge or the round edge on your coater? A 4/2 round edge is a lot of emulsion being laid down.

[alan802]

You wont have much luck with halftones when coating a 7/7, or a 4/2 for that matter.  I've never coated a screen 7/7, I think a 5/5 was the thickest I ever did and the stencil was about 300 microns thick, and I wouldn't have tried any fine halftones with that. To do fine line halftones, generally a thinner stencil is used but you can get halftones to come out on 200 micron stencils, you better have dense film and a powerful exposure system. 

If you coated a 150/48 with a 4/2 and the stencil wasn't thick, then something is really wrong.  That 4/2 should put you close to a 150 micron stencil, 100 micron EOM, which is about as thick as two business cards.  Depending on the openness of the artwork, shirt color and fabric  thread density, you should have been able to deposit a significant layer of ink.  It's hard to say if it could be a one hit white but if you're tring to print really wide open "stop sign" type designs, then you're wasting your time chasing a one hit print.   On thinner/smaller designs stencil thickness determines ink deposit but as your stencil's open area increases, it has less affect due to surface tension so you have to defeat that surface tension by having a thicker stencil and higher mesh tension.  There comes a point where to defeat that surface tension on a 12" stop sign print, your stencil would have to be very thick (not worth doing) and your screen/mesh tension would need to be extreme (80-100+ newtons, certainly not feasible) and simply doing a print flash print through a normal stencil gives you good results without having to get crazy with your screen specifications. 

Don't do what I did for a year and chase the one hit ghost and just let it happen when the job specs allow it to happen.  It's certainly possible and attainable on many occasions but sometimes you'll waste a ton of time trying to engineer a stencil for a one hit and it's not possible due to other variables.   I rounded up a few print swatches today that we're one hit jobs and I'll take pictures of them tomorrow. I think you'll be disappointed when you see just how limited the opportunities to achieve one hit status if you don't specifically pre-engineer every job for it.  Most of the time your customer wants a giant open area design so you have to give it to them with as little effort as you can so you can make money.

[alan802]

If there isn't a difference in ink deposit from a 2/2 coated screen and a 7/7 then "Houston, we have a problem" is all I have to say.  Stencil thickness is directly related to ink deposit thickness no matter what other variables you try to throw into the mix.  You can achieve different ink deposits with the same stencil thickness and what not by adding and/or changing many of he other variables, but that direct relationship has and will always be there.  You can manipulate that relationship but it's one of those screen printing laws that you can't ignore.

[JBLUE]

Alan go to bed.....lol  although I could and would talk shop all night. When are we going to get a chat for this place?

[Tagless Threads]

When you are coating your print side first (at least I do -- and then the ink side/squeegee side last) do you try to have the coater's edge barely touching the print side to increase your stencil?  I've always done that, as I've found that to create a thicker stencil, but sometimes I'm trying to have the coater touch the screen so little that it sags and drips.  Is that the correct method or should I be pressing harder against the mesh on the print side on my first coat(s)?

Thanks.

I always try to have good contact with the screen so I achieve an even stencil. Going slower or one more coat usually is the best way to achieve a thicker coat.

[ScreenPrinter123]

You wont have much luck with halftones when coating a 7/7, or a 4/2 for that matter.  I've never coated a screen 7/7, I think a 5/5 was the thickest I ever did and the stencil was about 300 microns thick, and I wouldn't have tried any fine halftones with that. To do fine line halftones, generally a thinner stencil is used but you can get halftones to come out on 200 micron stencils, you better have dense film and a powerful exposure system. 

If you coated a 150/48 with a 4/2 and the stencil wasn't thick, then something is really wrong.  That 4/2 should put you close to a 150 micron stencil, 100 micron EOM, which is about as thick as two business cards.  Depending on the openness of the artwork, shirt color and fabric  thread density, you should have been able to deposit a significant layer of ink.  It's hard to say if it could be a one hit white but if you're tring to print really wide open "stop sign" type designs, then you're wasting your time chasing a one hit print.   On thinner/smaller designs stencil thickness determines ink deposit but as your stencil's open area increases, it has less affect due to surface tension so you have to defeat that surface tension by having a thicker stencil and higher mesh tension.  There comes a point where to defeat that surface tension on a 12" stop sign print, your stencil would have to be very thick (not worth doing) and your screen/mesh tension would need to be extreme (80-100+ newtons, certainly not feasible) and simply doing a print flash print through a normal stencil gives you good results without having to get crazy with your screen specifications. 

Don't do what I did for a year and chase the one hit ghost and just let it happen when the job specs allow it to happen.  It's certainly possible and attainable on many occasions but sometimes you'll waste a ton of time trying to engineer a stencil for a one hit and it's not possible due to other variables.   I rounded up a few print swatches today that we're one hit jobs and I'll take pictures of them tomorrow. I think you'll be disappointed when you see just how limited the opportunities to achieve one hit status if you don't specifically pre-engineer every job for it.  Most of the time your customer wants a giant open area design so you have to give it to them with as little effort as you can so you can make money.

Going after that ghost, Alan... Will post one hit pics tomorrow (hopefully).  5/5 chromablue on 150 s mesh - rounded edge.... "Ka-Chow" (Yes, Cars reference).

[Gilligan]

Holy crap that is THICK!  When are done you can probably just peel it off.

[Screened Gear]

You wont have much luck with halftones when coating a 7/7, or a 4/2 for that matter.  I've never coated a screen 7/7, I think a 5/5 was the thickest I ever did and the stencil was about 300 microns thick, and I wouldn't have tried any fine halftones with that. To do fine line halftones, generally a thinner stencil is used but you can get halftones to come out on 200 micron stencils, you better have dense film and a powerful exposure system. 

If you coated a 150/48 with a 4/2 and the stencil wasn't thick, then something is really wrong.  That 4/2 should put you close to a 150 micron stencil, 100 micron EOM, which is about as thick as two business cards.  Depending on the openness of the artwork, shirt color and fabric  thread density, you should have been able to deposit a significant layer of ink.  It's hard to say if it could be a one hit white but if you're tring to print really wide open "stop sign" type designs, then you're wasting your time chasing a one hit print.   On thinner/smaller designs stencil thickness determines ink deposit but as your stencil's open area increases, it has less affect due to surface tension so you have to defeat that surface tension by having a thicker stencil and higher mesh tension.  There comes a point where to defeat that surface tension on a 12" stop sign print, your stencil would have to be very thick (not worth doing) and your screen/mesh tension would need to be extreme (80-100+ newtons, certainly not feasible) and simply doing a print flash print through a normal stencil gives you good results without having to get crazy with your screen specifications. 

Don't do what I did for a year and chase the one hit ghost and just let it happen when the job specs allow it to happen.  It's certainly possible and attainable on many occasions but sometimes you'll waste a ton of time trying to engineer a stencil for a one hit and it's not possible due to other variables.   I rounded up a few print swatches today that we're one hit jobs and I'll take pictures of them tomorrow. I think you'll be disappointed when you see just how limited the opportunities to achieve one hit status if you don't specifically pre-engineer every job for it.  Most of the time your customer wants a giant open area design so you have to give it to them with as little effort as you can so you can make money.

Going after that ghost, Alan... Will post one hit pics tomorrow (hopefully).  5/5 chromablue on 150 s mesh - rounded edge.... "Ka-Chow" (Yes, Cars reference).

Why so thick with that much coverage? Was this for printing on mesh one hit?

[alan802]

That's some good looking stencil right there, love it.  But, a one hit with that much open area is going to be tough.    The text with distress should look great with one hit, but the other areas I see looks like it's a bit too open.  Is that going to be white ink on black?  Can't wait to see the pics.  I took some pics of a one hit white on black AA's today so I'll try to get them uploaded later on.

[ScreenPrinter123]

But, a one hit with that much open area is going to be tough.

Johnny Raincloud.

[Screened Gear]

But, a one hit with that much open area is going to be tough.

Johnny Raincloud.

I have to agree with Alan. Another thing why did you use a 150 mesh? If the goal is to lay down a one hit you should use the lowest mesh you can and still hold the design. A 150 mesh with a 300 to 400 Micron stencil sounds "wrong". Don't get me wrong I am not beating you up. I do the wrong thing alot. I have printed with 305 mesh when I should have used a 123 because that is the only screen I had. I am always trying things that people say will never work. You know 50% of the time they are right. The other 50% I learn something. Have fun with your thick screen. My guess would be you will have to use alot of pressure to clear it. If you use too much pressure on a screen with that much open area you will not get the advantage of the thick stencil. You will be pushing the stencil into the shirt and your squeegee will close the gap of the screen and the shirt. What is that stencil like 500% EOM.

[ScreenFoo]

That is a heck of a stencil.

I have to agree with Alan. Another thing why did you use a 150 mesh? If the goal is to lay down a one hit you should use the lowest mesh you can and still hold the design. A 150 mesh with a 300 to 400 Micron stencil sounds "wrong". Don't get me wrong I am not beating you up. I do the wrong thing alot. I have printed with 305 mesh when I should have used a 123 because that is the only screen I had. I am always trying things that people say will never work. You know 50% of the time they are right. The other 50% I learn something. Have fun with your thick screen. My guess would be you will have to use alot of pressure to clear it. If you use too much pressure on a screen with that much open area you will not get the advantage of the thick stencil. You will be pushing the stencil into the shirt and your squeegee will close the gap of the screen and the shirt. What is that stencil like 500% EOM.

I'm no expert compared to many on here, but it seems to me that the pressure change is in the flooding of the stencil, not so much the printing of it--unless your ink is very thick, and/or you don't 'fill' your stencil.
The open area of a 150/48 is a higher percentage than an 125/70 or an 86/100.  Printing pressure from my observations is pretty well directly coupled to open area, all other variables (close to) the same.
I've been itching to get some of the S thread on to do some testing myself, but getting my ass handed to me right now...  (posting while screens are drying.    )

Looking forward to seeing what the print looks like.

[ScreenPrinter123]

[/quote]

I have to agree with Alan. Another thing why did you use a 150 mesh? If the goal is to lay down a one hit you should use the lowest mesh you can and still hold the design. A 150 mesh with a 300 to 400 Micron stencil sounds "wrong". Don't get me wrong I am not beating you up. I do the wrong thing alot. I have printed with 305 mesh when I should have used a 123 because that is the only screen I had. I am always trying things that people say will never work. You know 50% of the time they are right. The other 50% I learn something. Have fun with your thick screen. My guess would be you will have to use alot of pressure to clear it. If you use too much pressure on a screen with that much open area you will not get the advantage of the thick stencil. You will be pushing the stencil into the shirt and your squeegee will close the gap of the screen and the shirt. What is that stencil like 500% EOM.
[/quote]

Because a 5/5 on a 110 s mesh would drop entirely too much ink .

[ScreenPrinter123]

That is a heck of a stencil.

I have to agree with Alan. Another thing why did you use a 150 mesh? If the goal is to lay down a one hit you should use the lowest mesh you can and still hold the design. A 150 mesh with a 300 to 400 Micron stencil sounds "wrong". Don't get me wrong I am not beating you up. I do the wrong thing alot. I have printed with 305 mesh when I should have used a 123 because that is the only screen I had. I am always trying things that people say will never work. You know 50% of the time they are right. The other 50% I learn something. Have fun with your thick screen. My guess would be you will have to use alot of pressure to clear it. If you use too much pressure on a screen with that much open area you will not get the advantage of the thick stencil. You will be pushing the stencil into the shirt and your squeegee will close the gap of the screen and the shirt. What is that stencil like 500% EOM.

I'm no expert compared to many on here, but it seems to me that the pressure change is in the flooding of the stencil, not so much the printing of it--unless your ink is very thick, and/or you don't 'fill' your stencil.
The open area of a 150/48 is a higher percentage than an 125/70 or an 86/100.  Printing pressure from my observations is pretty well directly coupled to open area, all other variables (close to) the same.
I've been itching to get some of the S thread on to do some testing myself, but getting my ass handed to me right now...  (posting while screens are drying.    )

Looking forward to seeing what the print looks like.

Yup - hard flood, soft print. I'm looking forward to seeing it too - never tried a stencil this thick - probably won't ever again too .