The foundation of every good screen print is the screen itself. After a design is created, it has to be translated into a stencil on a screen. This process is called burning, or exposing, the screen. In this article, we’ll give you a quick overview of how the burning process works, and get you ready to make your first one-color screen.
In most cases, a stencil is made by placing a film printed with your design in black on the screen and then exposing light-sensitive emulsion with ultraviolet light. When the light hits the emulsion, it hardens. The black parts of the film block the light from hitting the emulsion, so the areas underneath the design remain soft and water-soluble. When you wash out the soft areas, you leave open mesh that ink can be pushed through.
The process of making your stencils works a little differently on Merchmakr than it does on a traditional screen printing machine, so even if you have experience screen printing, you’ll want to change your process a bit. The Merchmakr exposure process makes setup much easier, and eliminates the need for complicated hardware.
Note: This overview assumes you already have your film and a coated screen ready to go! Remember, before your screen has been exposed, you’ll want to use the safe light built into your Merchmakr exposure unit to avoid hardening the emulsion before you’re ready!
Make sure the platen is clean and free of debris. Put your coated screen into Merchmakr’s HotSwap clamp, face down. Make sure that the back of the screen is flat against the back of the clamp and the tab is properly seated.
When you’re printing, it’s usually a good idea to have about 1/8" of space between the screen and the platen. Screen printers call this off-contact. For the burning process, it’s best for the screen to be flat against the platen. You can control the off-contact using the elevator bolt located just behind the platen to raise and lower the screen.
Put the transparency film with your design on it in the screen. Line it up straight and center. A T-square will help a lot, if you have one. Once the film is where you want it, tape it to the screen using clear Scotch tape.
Take your Merchmakr Exposure Unit and flip it over so that the clear pane of acrylic faces down. Set the exposure unit into the screen. It should fit perfectly inside the frame of the screen. Once the exposure unit is in the screen, you can use regular lights for the rest of the process without an issue. Use the included bungee cord to strap the exposure unit down to minimize the amount of light that can work its way around your film and affect the design.
The Merchmakr Dual Cure Graphic emulsion that comes with the kit will expose most designs at 3 minutes. Merchmakr Tenacious E exposes at about 2 minutes.
When the timer runs out, remove the bungee, take out the exposure unit, and take the film off the screen. You might be able to see a faint version of your design on the emulsion already!
Take your screen out of the HotSwap clamp and move to the sink. Wash out the image area with lightly pressurized water. When you get the screen wet, you’ll see your design start to take shape. When the image is fully washed out and your design is completely clear of emulsion, you’ll have your stencil. Let it dry, and you’re ready to go!
If you have any trouble, make sure to check out Screen Exposure Problems and Solutions.
It’s a good idea to make sure the emulsion is as durable as possible, especially when you’re printing with water-based inks. A good way to do that is to set your screen outside in the sun, and let the rays of the sun continue the exposure process on the emulsion that remains. You can use this to help dry the screen and kill two birds with one stone.
Now you’re ready to start printing!
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