The first time you try to print on buttons, this is what you'd probably see: as you pull the squeegee across the screen and approach the button, the screen will ride up on the top of the button causing the ink to be deposited all around the button leaving a huge amount of unwanted ink on the substrate. The result would be quite messy and very unprofessional looking. Try the same with zippers, and you'll get a very similar look. Printing on garments with buttons or zippers, as you can guess, can be difficult. But with a little effort, and maybe an extra tool, it is possible.
Printing over a zipper or smaller buttons starts with the artwork. If you have script that runs horizontally across the shirt or sweatshirt, you can divide the artwork in half during the art and separation stage, or you could simply cut the film positive in half, measure the width of the buttons or zipper, then burn your image with that gap.
To avoid the excess ink build up during the printing phase, you'll want to have a "trench" to put the zipper or buttons in. You can purchase a pre-made platen, such as our Zipper Pro Dual Cut-Out platen, which comes with a pre-cut slot for fitting your zipper or buttons into. This is perfect if you know that you'll be doing a lot of jobs that involve buttons or zippers, as you can easily swap it onto your press and be ready to print.
For many, however, zipper and button jobs may be few and far between, and the idea of getting an entirely new platen for just one job might not appeal to you. If this is the case, then you can temporarily rig up a surface that will allow you to print without the need to purchase another platen.
If you choose to make your own, you'll need two boards that are about 1/4" thick. If you take a single board that is the same size as your platen, usually a 16x16", and cut it in half, that will work perfect. Mark the center line on your platen, and use spray tack to put your boards in place, leaving a gap or "trench" that is the same width as the zipper/button measurement you took earlier. Using a heavy tape, such as duct tape, to re-enforce the boards is a good idea, so that they don't shift around during printing.
If you're going with the DIY process, make sure you adjust your off-contact to compensate for the additional 1/4" height. You'll also want to enforce the area of the screen that will come in contact with the zipper or buttons by using a strip of thicker tape. Run a thin piece down the middle of the backside of the screen, between your image areas. This will help you avoid damaging your screen, as it is possible for the screen to split upon coming in contact with the zipper or buttons.
Spray the boards with a little spray adhesive, as you would normally, and load up the garment. Make sure the zipper or buttons are settled nicely into the trench you have made, making sure everything is good and flat. Now you can print on the substrate, and if done correctly, you will get a nice, smooth print. The only drawback to this method is having to divide your image.
If you want to print directly onto a zipper, you'll still need your trench boards or platen. If you're using trench boards, you may want to use slightly thinner boards. The slot in the Zipper Pro platen is shallow enough to work with. The goal here is to get your print surface as flat and even as possible for printing.
This time, your artwork will not be separated so that you can print right onto the zipper. Printing from side to side, rather than the traditional top to bottom stroke, is optimal here. This is helpful because you can use a little bit more pressure when your stroke meets the middle of the zipper, which helps to even out the deposit of ink on the surface of the garment.
No matter which method you decide to use, it will take some practice to get the hang of it. Some prints may not be 100% perfect, but with a little bit of time and effort, you'll get the hang of it. Don't forget to do a few practice prints before starting the real job, to make sure everything works well!