UPDATE: Be sure to check out my video for building a four color printing press to make the printing process much easier and more precise!
Some friends and I decided to run a Tough Mudder a while back. We wanted to make some cheap and easy shirts to represent our team “Department of Redundancy Department” so we got some cheap shirts from Amazon and printed them ourselves. Here’s how we did it!
There may be more effective way to print shirts on your own, but this is how to do it with a minimal amount of equipment.
You’re going to need a few things that you can get at most art stores, or Amazon.
You’ll need these things:
- Speedball Diazo Photo Emulsion Kit
- Screen printing ink (fabric ink for clothing)
- Screen Printing Frame
- palette knife
- Squeegee (we’ve had better luck on shirts with a rounded edge squeegee)
- Whatever you’re printing on
- a fan
- 1 or 2 utility lights with 150 watt bulbs
- A friend (they’re good for lots of things)
HOW IT WORKS
The process of screen printing is making a stencil and pressing ink through the uncovered part of the stencil, onto the surface (shirt, paper, whatever).
PREPPING THE SCREEN
First you have to prepare a screen, which means covering it with an even, smoothe layer of photo emulsion. The emulsion is a simple two part mixture. The two parts are bright blue, and an almost black-green, you can see that it’s evenly mixed when it’s green.
Once it’s mixed, pour it onto the screen and use the squeegee to evenly cover the space that you have. You’ll have to make several passes, on both sides of the screen to get it even. The covering doesn’t need to be thick, the MAIN THING is to make it EVEN. Try to get rid of lines, caused by overlap of squeegee passes. Once the application is complete, you’ll want to put the screen in a dark room (mainly just no DIRECT light) with a fan on it to dry. This usually takes 20-30 minutes of drying time. Make sure, if you are standing the screen on end, that no drips form. If they do, squeegee again before it dries.
Once the screen is dry, it’s ready to “burn”. You’ll need to print your design on transparency. The idea is that your exposing the emulsion to light, and the area underneath your design does not get exposed, which lets it be washed away.
Lay the transparency on the screen. You’ll want to tape it in place with clear tape. Make sure that you have the design facing the right direction. If you’re taping it to the BOTTOM of the screen, the design should be BACKWARDS.. if on TOP, the design should be FORWARDS. Also, be sure that the design is at least a couple of inches away from all edges of the screen so that you have room around the design when it comes time to print. This should all be done in low light (my photos seem brighter than the room actually was)
BURNING THE SCREEN
To burn the screen, we got two cheap utility lamps and put a 150 watt bulb in each.. To effectively expose the photo emulsion, you need a LOT of light (heat is part of the process too). Having the lights about 2 feet away works fine, but I know having them closer will speed up the process a bit. We laid a piece of glass over the design, to try to make sure that the transparency was a close as possible to the screen. If there’s any kind of gap between the two, you’ll get a little shadow, which translates to a blurry edge in the print. You generally want crisp, clear edges. So get the transparency as FLAT AS POSSIBLE.
Turn the lights on and wait about 30 minutes. This time is dependent on several factors, but it seems mostly tied to the distance of the lights from the screen. The end goal is to lift an edge of the transparency, and see your design, on the screen below, in the “unexposed green”. The burning process turns everything else a much darker green.
Turn off your lights and rinse the screen right away. Gently use a sprayer to knock out the unexposed design. This part will take a while. For a while you might think that it’s not going to budge, but keep at it. Gently scrubbing with a toothbrush was helpful to get it started too.
YOU HAVE TO BE CAREFUL HERE: If you scrub or spray too hard, you can take away emulsion that you WANT to stay, then you have to start over. Just realize that it takes a while, be patient and careful. Frequently hold the screen up to a light and look through the negative space to see if it’s fully clear.
Rinse until your design is completely free of emulsion. Once it’s done, I would put it in front of the fan again just to dry everything.
READY TO PRINT
Before printing, I used some painters tape on the backside of the screen to mask any spots where unwanted ink could get through. Make sure that no ink could come through the space that is at least the entire width of the squeegee, just to be safe. Also, this is a good chance to cover any spots where you may have over rinsed and blown a hole through the emulsion.
If you’re printing on a shirt, we found that folding a towel (GET OUT ALL WRINKLES) and placing it IN the shirt, is helpful. It blocks the ink from bleeding through to the other side of the shirt, and it makes the surface give a little, as you pull the squeegee across the screen. Then you’ll need to lay the screen on the shirt, getting the design placed where you want it. We’ve used several methods for centering, like laying a string down the center of the shirt, then laying the screen on top and aligning the design’s center to the string. We also laid the shirt on a piece of MDF, then traced the shirt, so that the next shirt laid in the exact same spot.
The process of printing is simple, but it takes practice to get the technique down (which I haven’t). Using a palette knife, lay out a good thick bead of ink above the design. You’ll want to over do it here, rather than under do it. Sometimes, you may even want to add another bead further down the design, for example, in between lines of words. You’re pushing ink through the screen, so you want to make sure that there’s enough ink to cover then entire design.
Now, have someone hold the screen in place.. and I mean REALLY HOLD IT. If it moves, you’ll have a nice big smudgy shirt. With the screen locked in, put the squeegee down at a 45 degree angle PAST the ink, and pull towards you. Try to keep the downward pressure the same (this is tougher than it sounds.) and make sure you pull all the way across and PAST the design.
Before you lift the screen, I’d suggest someone hold the shirt down to the table so the ink doesn’t glue the shirt to the screen as you lift it. Also, lift the screen from one side, not straight up. Now, theoretically, you’ll have a design printed on your shirt!
Let the ink dry (the fan helps again). Once it’s dry, you need to heat set it so that the ink bonds to the fabric better, and lasts longer. This is as simple as laying a piece of paper over the design, and ironing (on cotton setting) over the paper for a minute or two. Failing to do this will justs shorten the life of the print. If you’re going for the worn/vintage look, maybe NOT heat setting it is the way to go.
- Rinse the screens out as soon as you’re finished printing. The screens will last longer and your design will be reusable.
- If you print multiples, be sure to check the bottom of the screen between each print. Eventually ink will start to bleed under the edges, and will cause the next print to be blurry. If it’s bleeding through, rinse the screen off and add new ink.
- Test print on an old shirt before you try it on your expensive shirts, there are lots of things that could go wrong the first time.
- Make sure that you get FABRIC inks when printing on clothes. There is a difference.
- If printing a light color onto a dark shirt, try to find an “OPAQUE INK” so that the color stays more true to what you intend.
Getting the print to turn out really well takes a good bit of practice, but once you get the hang of it, you’ve got a really handy way to make custom shirts, posters, whatevers!
Got a tip or some advice for screen printing? I’d love to hear it in the comments below!