What you need to know to screen print (General Info. and Tutorial)

[Sanderpoo]

I was reading some threads and it seems like lots of people have lots of questions about screen printing and are kinda hazy about the whole process and what you need and don't need.  So, I'll try to clarify some things.  I'm currently in the last week of my Screen Printing class at CMSU (I have an A in the class, so don't worry that I'm just some tard college student), so I think that I should be able to cover the basics and answer any questions. Onward to the actual information!!

I. What you need:
      A.  Frame
      B.  Mesh
      C.  Stencil
      D.  Ink
      E.  Squeegee

Elaboration on these things:

A. Frames:  There are 2 types, Rigid and Retensionable. 
         1.  Rigid frames can be bought with mesh all ready attached to them.  These type are best for at home printing because they already have the proper tension and you won't have to buy the mesh separately.  After some heavy use they will lose tension, which is a bad thing but no big deal because you probably won’t be using them all day everyday and they are fairly cheap.
         2.  Retensionable frames are not what you want.  They may be called Newman Roller Frames.

B. Mesh:  When you buy a rigid frame, you are going to want to know what type of mesh is on it. Also, if you are going all gung ho about it and stapling fabric to wooden frames, this section should help you decide what to use.
   1. Fabric Types
            a.   Silk is never used. Ever.  Don't even think about it. It won't look good.
            b.   Nylon is rarely used by businesses except for on contoured substrates (like beer bottles, golf balls, you know, roundish stuff)  However, I have seen it used by some crafty folks and from the results, my guess is that it isn't holding super nice detail.  But it can be done!
            c.   Polyester is the weapon of choice for businesses (like 95% of screen printing uses this).  Now, this doesn't mean you can go grab that pea green sports jacket from the seventies, staple it to the frame and actually have it work.  The mesh is woven to be, well, meshlike.
        2.  But wait there is more to mesh!
Different types of printing use different threads per inch(that is the random seeming number that is somewhere in the title of what you are getting). Here are the usual number ranges and what you can print with each:
           a.  60 to 80- Glitter inks, doesn't hold detail at all.  Seriously, no detail.
           b.  110 to 155- T-shirts, holds pretty good detail. Could probably print on paper and stuff. This is probably what you want.
           c.  180- Used for underbases on dark shirts and tightly woven fabric.
           d.  230- Uncoated paper, plexiglass
           e.  Anything above those- You don't need 'em.  You probably won't need anything above a 155 unless you are printing on something that doesn’t absorb ink very well.

C. Stencil(Emulsion):  You have several different choices with these.
        1.  Direct emulsions is a liquid that you coat both sides of the screen with. There are two types, go with Diazo. This type is pretty cheap.
      2.  Capillary comes in sheets that are fast and fabu to apply to the screen (these are my favorite).  They are more expensive but easier and more consistent to use.
      3.  Magical at home glue concotions look like they work okay, but seem like a pain in the ass.  Also, I’m thinking that these aren’t going to hold detail worth a….something that isn’t good.  So, if you are wanting some good detail and ease of use, go with #1 or 2.

D. Ink:  There are a couple different types for different job.
      1.  Plastisol is used for t-shirts, stuff you wear.  To dry it you have to heat it up to at least 320 F, otherwise it will wash off and you will be sad and cry.
      2.  Enamel is used for cards and paper stuff.  It is water based so it’ll dry all by itself if you just leave it out. 
      3. House Paint is used for concert poster that dude print in their basement. It is good priced and comes in lots of colors. I wouldn't use this on and shirts or anything.
     4.  Other stuff-  I’ve seen that use guys are using other things like Speedball and what not.  I don’t know what these are or how well they work.  The main thing I would be worried about is there durability when you are washing them.

E. Squeegee:  This is pretty basic.
      1.  Uh, just go buy a cheap one with an end that is shaped like a rectangle and you’ll be fine.
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Okay!  I hope I didn’t wear you guys out with all that information.  I tried to sparse it down to just what you need to know to print at home.  (I could have gone on and on about squeegee durometer and shore A, but you don’t need to know that crap.  Hell, I doubt I even need to know it.)  Hopefully this is useful information and will help you kids figure out what you want to use.


Next time on Cassandra Rambles About Screen Printing:  How to get ready to print!!

[professor_ping]

THANK YOU so much for doing that!
I've been searching all over this site and others for a good, comprehensive guide to the ins and outs of getting started on screening, and it's been HARD to find any.  This is awesome.  Can't wait to get some more craft funds together. 

(Sadly, my boyfriend has put me on a much-needed budget.  I'm knitting, painting, sewing, and a bunch of stuff and he said I needed to trim down to one or two projects at a time.... Whatever that means! )

[Sanderpoo]

Alright, in the last extremely long post I told you what you needed to know about your tools.  In this one I’m going to let you in on the magic of actually setting all this stuff up and printing.  Hopefully this one won’t be quite as long as the last.(  Feel free to cross your fingers.)

II.  Prepress:(this is all the stuff that you need to do to get ready to print)
   I’m going to skip all the voodoo involved in getting you graphics ready for printing more than one color.  I can cover that in a later post if there is some interest in it. So, here is what you need to do.
       1.  Print out a positive of your image on some clear plasticy stuff.  You could also use regular transparencies, just make sure that theyou can't see through the black.  When you print out your design, change whatever color it is in to black so that only black will be on the print out.
      2.  Now, you need to get your screen ready to print.  This has a lot of steps to it, so brace yourselves.
           a.  If your screen is brand spankin’ new, you need to abrade it so that your stencil will stick well.  To do this, just take a soft bristle brush and lightly rub it on the screen.  Only do this when the screen is brand new.  (Only when brand new.  Seriously, I’m not kidding.)
           b.  Next you wash the screen and if you happened to buy a kit with a degreaser in it, use that. Then spray it down with water.
           c.  Let it dry for about an hour.  (To speed up drying you can use a shop vac and suck off some excess water after you wash it.)
           d.  Apply your stencil to the mesh.  How you do this depends on the type of stencil you are using.
           e.  Let it dry, this will take longer to dry.  I would recommend just letting it dry over night, or while you are at work.  If you are extra ancy, three hours is probably the bare minimum.
           f.  Expose your image.  The print out should be face up and directly in contact with the stencil on the flat side of the screen.  (The side where if you were to lay it down, it would be completely flat against the floor.)  The time that you expose it for depends on what type of stencil you used and what type of light you are using.
           g.  Wash the screen, and the positive of your image should washout of your screen.  It is like magic!
           h.  Let the screen dry for about an hour.
            i.   Now, then if you have Blockout slather some around the edges of your stencil and let it dry for an hour.  If you don’t have Blockout, don’t panic.  Just take some trusty duct tape and tape off from the edge of your stencil to the frame.
           j.   Now pat yourself on the back and relax for a little bit, that was all tough work.

III.  Printing
   Okay, when you print, there is one very important thing.  Your stencil should absolutely, under no condition, be touching what it is you are printing on.  You can’t just lay your screen down and squeegee away.  This will make you picture all smeary and you will cry.
        1.  My recommendation is that you find a couple pieces of wood that are about and 1/8th of an inch tall.  Take these and put them under the edge of your frame.
        2.  Now, pour some ink along the edge of the screen farthest away from you.  Take your squeegee and pull some ink toward, covering the stencil.  Don’t apply pressure, just gently cover the area that you are going to print with ink. (This covering the stencil with ink is called flooding.)
        3.  Next is the printing stroke (exciting!) take your squeegee(with both hands), press down and away from you.  You need to hold your squeegee at an angle so that you are printing with the edge of the squeegee.  You should hear a nice “Shhhhreeeeeeppbb” sound.
       4.  OMG!!! You just Screen Printed!  I’m soooooo freaking proud of you! Dance a jig!
       5.  Now do a flood stroke and print stroke everytime you print something.

IV. Cleaning all this stuff up
   Some of this depends on what type of ink you’ve used, so I’ll try include all the possibilities.
      1.  First, you aren’t going to want to waste all that ink that is on your screen.  So take something a popsicle stick(or one of those paint stirrers that they give you for free) and scoop up as much in as you and put it back in the can.  Unless it is enamel ink and is drying and icky, in which case, just dump it.
      2.  Next, if you have some Press Wash, dribble some on and try to take off as much of the extra ink as you can.  If  you don’t have press wash, I’m honestly not sure what you can use as an alternative.  Perhaps something like paint thinner, but I have no idea how that will react with the stencil and mesh and what not.
      3.  Now you need to rip off that duct tape and wash off that stencil.  You can get stencil remover that will make them wash of easy peasy.  Other than that, I’m thinking some soap and water might do the trick.  If you are having to scrub really hard, switch to something else.  That stencil isn’t going to dissolve in water and the more you scrub the worse off your mesh is going to be.
      4.  Take a nap.  This is tiring stuff.  I’m tired just typing it.  Whoo.


This is the hardcore stuff, and I’m thinking that I probably took some stuff for granted and cut corners on my explaining.  So if there are any questions, feel free to ask, and don't worry about feeling stupid, I won't mock you too much.

Next up:  Tips, Tricks, and Everything else that is good to know!

[nitachondria]

I'm a little curious on your steps III and IV:

I'm trying to picture this printing 1/8" above your paper or fabric and I can't even begin to comprehend how you do it. I've not gone to school for this, but I've been screen printing for three years and have always just help the screen down with one hand and one foot and printed with my free hand.

as far as any water based inks (which I'm guessing most of the people on here use) all you ahve to do is spray it out with a hose. you may have to rub off some paint with your fingers, but I would never scrub the screen. scrubbing can cause the emulsion to lift.

[Ryu Otera]

 
           
         

III.  Printing
   
        1.  My recommendation is that you find a couple pieces of wood that are about and 1/8th of an inch tall.  Take these and put them under the edge of your frame.
        2.  Now, pour some ink along the edge of the screen farthest away from you.  Take your squeegee and pull some ink toward, covering the stencil.  Don’t apply pressure, just gently cover the area that you are going to print with ink. (This covering the stencil with ink is called flooding.)
        3.  Next is the printing stroke (exciting!) take your squeegee(with both hands), press down and away from you.  You need to hold your squeegee at an angle so that you are printing with the edge of the squeegee.  You should hear a nice “Shhhhreeeeeeppbb” sound.
       

1.)does the ink "fall" down onto the surface? how does the ink get to the shirt?
I heard of people putting it directly on and the paint sticking to the surface when you pull the screen up
2/3.)So pull, then push the squeegee???

[spurtiic]

July 14th's Crafters Coast to Coast featured a screen printer.  She made it look SO easy.

Step 1.  Find a picture you like and "photoshop it" b/w (stenciled).
Step 2.  Print it on acetate.
Step 3.  Make a skirt, expose the stencil, squeegee and PRESTO!

Ok so it's more complicated than that but it was still fun to watch it. 

[Sanderpoo]

I'm a little curious on your steps III and IV:

I'm trying to picture this printing 1/8" above your paper or fabric and I can't even begin to comprehend how you do it.

Whoa! I disappeared for a couple months there, but now I'm back and it is 1 am, so what better to do than answer your burning questions.

Okay, the whole 1/8" thing. This is just a gap between what you are printing on and your frame/mesh.  It keeps the image from being smeary.

1.)does the ink "fall" down onto the surface? how does the ink get to the shirt?

The ink is pushed into the openings in the mesh by the squeegee. Then the tackiness of the ink causes it to stick to the printed object while the mesh is snapping back into it's original place.

Okay, that was unnecessarily complicated, lets just say that you are kind of pushing it through the screen with the squeegee.

2/3.)So pull, then push the squeegee???
Either way, it really doesn't affect the quality of the image.



 
Now that I read back through this, I find it too complicated for at home printing. I'm going to do some editing.

[smarmyclothes]

I'm trying to picture this printing 1/8" above your paper or fabric and I can't even begin to comprehend how you do it.

i also have never had a gap between my screen and fabric.  but apparently this is the "correct" way to do it, or so i was told at some point.  doesn't make sense to me, and my prints came out find with the screen coming in complete contact with the fabric. 

[Sanderpoo]

I'm trying to picture this printing 1/8" above your paper or fabric and I can't even begin to comprehend how you do it.

i also have never had a gap between my screen and fabric.  but apparently this is the "correct" way to do it, or so i was told at some point.  doesn't make sense to me, and my prints came out find with the screen coming in complete contact with the fabric. 

If you are printing something low resolution, it probably isn't very noticeable.  If you are printing a really sharp line on paper, you'll be able to tell.
Here is how it works:
Imagine a piece of elastic laying on a table. Now, if you pressed your finger down on it and then pushed your finger away from you, that piece of elastic would stretch out, right?  And when you pick your finger up, that elastic will snap back to how it originally was.
The mesh on your screen essentially does this exact same thing, but certainly not to the same extent. The squeegee stretches the material out and then the material goes back to how it was once the squeegee is lifted.
So, imagine that piece of elastic again, but now think about it on top of wet ink.  It'll smear.
There you go.

[smarmyclothes]

aha, thanks for that explanation.  it occurs to me now that i also could have very well had a gap and not even known about it, heh.