AfterDark: April 2010

Steps to Screen Printing Pt. II

Continued from Steps to Screen Printing...

6. Take your newly exposed screen and lay it, frame side up on the t-shirt. You will need to keep the screen steady as you pass the squeegee over it, so use clamps or a willing friend to hold it down.

7. Choose the color ink you want. Using a spoon or Popsicle stick, begin laying some ink across the top of the screen-try to use an even amount of ink throughout this process.

8. Take your squeegee and place it above the ink on the screen. Holding it at a 45 to 60 degree angle, push down on it and begin passing the ink through the screen in a downward motion. When you reach the bottom, repeat the process-this time going up. Never move the shirt while doing this, since it will mess up your print.

9. Lift the screen off your shirt. You should have a brand new freshly painted t-shirt! You are free to print out another shirt, just repeat step #8. If you're done printing, leave your shirt where it is and begin the process of cleaning the ink from your screen before it dries-it's a pain to clean up if it does, so avoid it at all cost.

10. Using the squeegee, take any leftover ink from the screen and return it to its container. Take your screen to the nearest bathtub or sink and using soap and hot water, wash your screen. Use mineral spirits to scrub off stubborn ink from the screen. Once dried, you can keep the screen as it is in case you want to print out the same design in the future or you can reclaim the screen.

To reclaim the screen, you will need stencil remover to help remove the dried on emulsion. Apply the chemical on the screen and blast it with hot water, using a nylon bristled brush to break away the emulsion. Afterwards, degrease the screen using Simple Green or the unscented dish washing soap and let dry. Your screen is now be ready for another design.

An outline of the image you've just printed will most likely appear on the screen after you've cleaned it. This is called a ghost image and is perfectly normal, though slightly annoying. It shouldn't interfere with any future printing as long as the screen is clear or translucent when you hold it up to the light. If you find there is still some ink in between the screen’s mesh, use a degreaser and scrub some more.

Picture of ghost image. You can still use the screen as long as there's no ink blockage in the mesh.

11. Back to the shirt. Using the heat gun, hold the gun four to five inches away from the shirt and begin drying your printed design in a circular motion, spending no more than a few seconds on a particular spot to prevent scorching. Remember, the heat needs to reach at least 320 degrees Fahrenheit to fully set the ink in. Use the temperature gun to gauge how hot the heat coming from the heat gun is. Once finished, you should have a fully dried shirt.

Congratulations! Pat yourself on the back, 'cause you've just printed your very first shirt!

Steps to Screen Printing

We've covered the materials needed, how to make the screen, and the exposure lamp. We've also covered the images to print. Now it's time for the fun stuff. The actual screen printing.

1. Degrease the screen: Using regular unscented dish washing liquid (absolutely no orange, lemon, or whatever fruit scented soap) or Simple Green, wash any dust or oils from the screen and let it dry. The dish washing liquid needs to be unscented because the oils that make the soap scented are similar to the oils you're trying to get rid of in the first place.

2. Tape off the edges of the screen. This will make cleaning much easier and save not only your ink but emulsion as well, which we'll be using to coat the screen. Following the directions on the emulsion container, spread your prepared emulsion in an even coat on both sides of the screen using the scoop coater/emulsion trough. If you don't have one, simply use the squeegee, holding it at a 45 degree angle-clean it afterwards.

Depending on your emulsion's instructions, coat the screen in a dark place where no natural light can go through. You can use a simple bug light to help you see what you're doing. Take some push pins and tack them onto the wooden corners of the screen, this will allow the emulsion to dry without coming into contact with the floor. Finally, let the screen dry in the dark in a horizontal position. You can take off the pins when done.

3. Draw or print your design onto a sheet of transparency paper. The design has to be opaque-absolutely no light can shine through the black ink. If you have to, print out two transparencies and place them on top of each other.

4. Now, you are ready to expose. Turn on your handy dandy exposure lamp. Place black foam (or cardboard painted black) underneath your screen.

Position your transparency wherever you want it on the screen and place a piece of glass (taken from a picture frame or found in Home Depot) over it, this will weigh down the transparency so it doesn't move anywhere. Because the heat could crack the glass, keep a small fan turned on nearby.

Burn the screen for at least 18 to 20 minutes. It could be more or less depending on how far the bulb is from the screen-usually, the closer it is, the less time it should take to expose.

When finished, run your screen under the shower with lukewarm water. The emulsion will wash away, leaving your design fully visible. Like step #2, tack four push pins onto the screen to allow it to dry throughly.

5. Lay your t-shirt flat on a table. If needed, you can use spray adhesive to keep it from moving. Remember to place a few sheets of newspaper or a piece of cardboard on the inside of the shirt to keep ink from going through to the other side.

To Be Continued...

Let's Talk Images

A t-shirt is all about images. A message you want the world to know or a picture you want your friends to see. What you print is just as important as how you do it.

You've found the perfect image that would look great on a shirt, how are you going to print it?

Simple. Sort of. You need to take that beautiful, colorful picture and turn it into black and white. Why? You'll find out in just a minute.

Remember the transparency paper I listed in the materials section? Since we're screen printing via the emulsion method, our image needs to be printed onto one or two transparencies in black ink. You can choose whatever color paint you want to print the shirt, but your transparencies need to come out in black only.

Say you've chosen this picture:

Yay, Asian Kung-Fu Generation!

Ahem. Using your favorite imaging software (I'm using Photoshop, but you can certainly use Gimp, Paint, or even Word) and turn the image into black and white. Think of the image as a stencil-if you were making a stencil, the black part of the image would be the part you cut out so that when you ran the paint roller over it, the image would print.

Similarly, the black ink on your transparency will serve to block out the ultraviolet rays from your exposure lamp. When you wash out the emulsion, the parts previously covered by the black should wash out easily and thus make your image t-shirt printable.

Here's how the picture turned out. Now just turn that printer on and hit 'print.'

While you wait for your printer to finish printing, enjoy this music video by

Asian Kung-Fu Generation...

Exposure Lamps

I take my newly constructed screen with the emulsion I've prepared. After I let it dry, I pick up the screen and locate the image I'll be using. I plan to go outside and expose the screen the natural way, with the sun. To my surprise, however, as I open the door I realize that it is just beginning to rain. 'No screen printing today, then...'

Not if I have an exposure lamp. Exposure lamps or units are useful for preparing a screen for screen printing. Though we can use the sun, it is difficult to control the amount of UV ray exposure that the screen is getting. Sometimes it may be too little and the emulsion will wash out in unintended areas, other times it may be too much and you'll end up baking the emulsion directly onto the screen-which is not good. Other times the weather just won't allow it.

To build an exposure lamp is actually pretty simple. All you need is some PVC pipe, a 500 watt halogen work light, a saw, and a power drill, all conveniently found at your local hardware store. Below is a video that gives more in-depth information on how to build one...

Following the instructions in the video, I created this:

Not bad. For someone who is mechanically challenged. It even stays upright.

AfterDark

Steps to Screen Printing Pt. II

Steps to Screen Printing

Let's Talk Images

Exposure Lamps

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