Screen Printing at Turdus Concept: BackstageMay 30th, 2018 / Screen Printing
n today’s post, we’ll announce the mystery and we’ll show you how we make our shirts. Prints on shirts can be made using one of two common types of paints: water or plastisol paints. Water paints, as the name suggests, are manufactured on the basis of water and it is diluted. It is the cheapest method of printing and the earliest. The second type of inks used for screen printing are the plastisol paints mentioned above. Vinyl-based products are characterized by a much higher durability than water-based paints, are more flexible and have better coverage. The difference in the printing of dark fabrics is particularly noticeable. It is this type of paint that we make our prints.
Starting the party!
We start each print with the preparation of templates printed on a transparent foil with black ink. Thanks to them, it will be possible to reproduce the shape of the future print on the sieve.
The next step is covering previously prepared sieves with a photo-curing emulsion. After the sieves dry (about 40-60 minutes depending on the ambient temperature), we can proceed to the proper screening. The process of covering the sieves with emulsion, drying and recording and burning the sieves is carried out in a poorly lit room, preferably using a yellow bulb (the one used in the darkroom).
Place each sieve on the shoulder of the printing press, and then one by one, register each template on the work surface, and then on each sieve. This process consists in placing all the templates at the same distance from the inner edges of the sieves (preferably in the middle of the sieve), so that after exposure, it is possible to overlap the position of all layers of paint in a multicolored print. This process is all the more complicated, the more colors we have foreseen for our print. The most demanding prints are those made in CMYK format, ie with the reproduction of all possible colors. The reason is the need for very accurate registration of templates and sieves.
After registering the templates and checking their position on each screen, we can start firing. Place each sieve on the work surface, press the template with clean, transparent glass, and then, using photo tubes (eg softbox), we light the screens until the emulsion hardens in places exposed to light. Typically, this process takes about 4-7 minutes, but its length depends largely on the thickness of the emulsion layer, the distance of the lamp from the sieve and the power of the lamps themselves.
After burning the sieve and removing the template, there will be a difference in the colors of the emulsion exposed from the covered one. We wash each spent sieve thoroughly with water, using a soft brush or using a high-pressure cleaner, if we have one.
We repeat the firing and washing process with each sieve prepared. Finished sieves leave to dry completely.
When the sieves are registered, burnt and cleaned, you can start printing. The ready sieves are placed in the arms of the press and we check the position, correcting the inclination and distance from the worktop. There should be a small space between the sieve and the top to allow the sieve mesh to be pressed against the fabric to squeeze the paint through the sieve. After making sure about the position of each sieve and the necessary adjustments, put on a worktop designed for printing a shirt, blouse or any other substrate.
We apply paint on each sieve to the width of the future print and gently spread it over the entire surface of the burnt template. Then we leave the press arm with the sieve above the shirt and pressing the squeegee with a squeegee, we print a single layer of paint on the fabric. We raise the sieve and heat the paint layer using a heat gun set at a temperature of about 150-170 degrees Celsius or burn with an infrared heater (the latter method is recommended for plastisol paints.) The first one is also good, but it is dedicated to water paints).
The above process is repeated with each color that is provided in the design of the print. We warm everything up at the end again. The shirt is ready!