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ScoutParent

Screenprinting Tips Please

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Screenprinting you say?

 

Yes, I did it professionally for about 10 years. I'm a master screenprinter.

 

I need more info before I can help though.

 

1. Have you printed before or are you asking because you have no experience whatsoever?

 

2. Camp? Do you mean summer camp?

 

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No experience in making the screen. Would like to use the photo emulsion method. Have a design with black and white. My question is which part will print--the part that is black or the part that is white (so we get it right before we do all that work to the screen)

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Please excuse me if you know some of this already.

 

First off some common definitions so we can be on the same page

 

Screen: Screenprinting mesh pulled taughtly over a wooden or aluminum frame.

 

Stencil: The emulsion coating on the screen that actually carries the image.

 

The artwork question first.

The black will print and the white will not. Lets say you took a white sheet of paper and wrote BSA on it in black. All you want to print is the letters BSA and you intend for the white area of the paper to be T-shirt (or whatever you are printing on)

 

Screen prep:

Ok assuming that you have or have built a screen. The first thing to do is abrade the screen mesh. Get some comet and a plastic scrub brush and throughly scrub the screen and rinse with clean water until no cleaner residue or suds remain. This is necessary to remove any oils or contaminants in the mesh and also roughs up the mesh very slightly as to give it a "tooth" that the emulsion will adhere too. This is necessary even if the mesh is brand new as there will be contaminants on if from the manufacturing process.

 

Let the screen dry in a place without much airflow (no breezes or fans)and protected from stuff that might fall on it like dust. Anything that gets on your screen now will cause pinholes that will allow ink to break through your stencil.

 

Everything from this step forward MUST be done in a red lighted room. ANY exposure to light will ruin the emulsion.

Once the screen is completely dry coat the screen evenly with the emulsion. A scoop coater works bestfor this. It is important to apply an even coat of emulsion. To coat the screen first coat the side of the screen that will contact the shirt and coat it with one even pass. Do not stop or change speed. Then coat the ink side of the screen using the same technique. Let the screen dry in a flat level position with the ink side up under red light or in complete darkness.

 

How the image is made:

Your artwork is made into what is called a "film positive" the film pieces you use on an overhead projector are film positives. What you positives will look like is a clear piece of film with the letters BSA in black on it. You will then take that film positive and place it (tape it) on the SHIRT SIDE of a prepared screen (meaning coated with emulsion and dried).

 

Then you will take the screen and expose the emulsion to a strong light source. The light needs to pass through the positive. The black sections on the positive (the letters BSA) will block the light from hitting the emulsion. VERY IMPORTANT: The black information on your film positive needs to be as opaque as possible. Hold it up to a light. If light passes through you will have problems getting a good stencil.

 

The emulsion that is exposed to light cures (hardens) and the area you blocked with the positive (BSA) does not cure. You then remove the positive You may now leave the red lite room and wash the screen with strong spray of water. The uncured emulsion will fall off the screen leaving you with a negative stencil. Pat dry with a lint free towel and allow to dry. You can even use a fan now.

 

When dry look at the screen with a light source behind it and use some of your extra emulsion and a small brush to fill in any pinholes or thin spots in the stencil. If you don't ink will break through and onto your shirt. We used to take small pieces of card stock and coated the non-printing areas with another coat of emulsion to be sure. It's a good way in ensure a strong screen. When your touch up is done just let the emulsion dry and bring it out in the sun for a couple of minutes to harden it.

 

Hope this helps. If you need anymore info just shout. If you click on my profile you can go to our troop site and email or call me directly from there.

 

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Mike

This is some good information; your tips address questions that I had on the process. I'm wondering about your note on opacity when making the artwork master; can you just pump it out on a laserjet or inkjet printer (maybe setting the font to BOLD? or looking into printer options) or is it better to paint over the original toner? Might you gain something by stacking multiple copies of the printer output?

Would you suggest working with some sort of a kit for we amateurs?

Any thoughts on Tshirt quality? How about printing on a pocket?

Thanks for sharing your expertise!

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We tried this and the first screen turned out ok but the second one was great! We used the inkjet printer with transparencies. We found that setting it on the densenst setting and printing two was the best way for us. Then we stapled the transparencies together in the middle of the paper strip.

 

The kit we purchased was one made by Speedball available at Arts & Crafts stores. It contained the screen, photo sensitizer, emulsion liquid, screen filler, drawing fluid, squeegee and textile ink. It was about $ 50.00.

 

Thanks again for the help, Mike!

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Glad it worked for you but it is not reccomended that you stack positives to shoot a screen. The reason why is that light will creep around the edges and your stensil (ans subsequently your print) will not have a sharp and strong edge to it. A condition known as sawtoothing. Now for what most kitchen table printers are doing stacking positives will work just fine just try to use as few as possible. Just be sure you aren't trying to do any fine detail work. The best way to get it opaque is to use a mechanical pen like a rapidograph pen and use waterproof ink to darken the positive. Rapidograph pens cost about $20 a pop. Get a medium to think line pen.

 

But hey, it worked right? Theory is nice, results are better.

 

Kits work great and just I would suggest the one ScoutParent mentioned made by SpeedBall.

 

T-shirt quality. You get what you pay for. I have printed promotional quality Ts that you could read a newspaper through. Needless to say a thin cheap T prints poorly. There just isn't much material for your ink to grab onto. Most home printers use waterbased inks that sit into the t shirt material. You will want a thicker shirt to give you a nice durable print.

 

Y'all might want to find a commercial t-shirt supplier to get shirts from. There are many of them on the net now. Just search for "imprintables". All of us have tax ID #s so why not use them? Keep in mind your pricing will depend on the volume you buy. See if you can find someone who is sympathetic to the BSA and ask if they could find it in their hearts to give you Case Pricing. Case Pricing is where you want to be. As far a brands I'd suggest Hanes Beefy Ts, Anvil, Fruit of the Loom and other larger names. Russel Athletic always has quality control issues. Be sure to inspect every shirt you get when you get them and send back anything that isn't up to snuff. Don't be nervous about sending back only T either. That's business as usual in printing.

 

Printing on a pocket.

Get a piece of plywood or masonite about 5 or 6 inches wide and about 2 feet long. You want it to be as smooth as possible and as rigid as possible. Cut the material so that it will fit into the shirt pocket without distorting the shirt. Be sure to round it off so the end of the board looks like a U when looking down on it. You have just built a pocket palette.

 

Clamp the palette to a sturdy table so that your U end is pointing towards you and hanging over the edge of the table.

 

Get some spray tack adhesive and lightly mist the very end of the pallette.

 

You will want to tape the backside of your screen in case the spray tack tries to pull your stencil off the screen (and trust me, it will try reeeal hard to do just that.)

 

Fit the pocket over the end of your palette and then take it off to break the tack. The tack should be just that, only tacky enough to just hold the shirt in place but not be hard to take off. Practice loading and unloaded the shirt until you feel confident that you are not distorting the pocket. If you disort the pocket and print on it you design will be a lopsided and funky looking. The rest of the shirt should just be hanging by the pocket. It would be a good idea to get a tall cardboard box for the rest of the shirt to sit on rather than just hang. Less chance of distortion that way.

 

When ready, position your screen and print that sucker.

 

The difficult part is removing the shirt without letting it touch itself and smudge. This why is is important not to over-tack the palette. If you practiced loading and unloading you will see exactly what I mean. Most folks over-tack the first time and "nail" the shirt to the palette. When you try to remove the shirt it will "snap" like a rubber band and usually ruin the print.

 

Hope that helps.

 

Oh, while you are at it use this a chance to work on Graphic Arts Merit Badge.

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