Things You'll Need
Glass, 1/4 inch thick
Screen printing ink
The best technique for printing on plexiglass is screen printing, also known as silk screen or serigraphy. Standard screen-printing tools and techniques may be used to print on Plexiglas, with the exception that the proper ink for Plexiglas must be used. The ink must be allowed to dry for an exceptionally long time to maintain the integrity and durability of the print.
Create or select an image to print on Plexiglas. Images may be created on paper or on a computer. For paper images, scan into the computer. For computer-generated images, open a file in a word processing or graphics program. Compose an image using words, photos and illustration elements.
Print the image on a piece of clear vellum. This is called a film positive. If there is more than one color in your image, print each color separately on clear vellum. Select grayscale printing as the film positive needs to print in black.
Coat a screen frame, also know as a silk screen, with photo emulsion in a dark room. Coat both sides of the screen and remove excess emulsion. Let it dry overnight. Place screen frame face down over a piece of foam rubber cut to fit inside the frame. Place the film positive face down on the screen frame and place the 1/4-inch glass over it.
Hang the halide light 18 inches over the glass, film positive and screen frame. Turn it on for five to 10 minutes, according to the exposure time recommended in the photo-emulsion instructions. Spray the image on the screen with warm water under medium pressure. When all the emulsion is out of the design area, blot both sides of the screen with newsprint and let dry. A screen frame must be coated, exposed and imaged for each color in your design.
Place Plexiglas on a flat surface. Place the imaged screen frame over it and put a thick line of ink in the screen frame opposite yourself. Jacquard professional screen printing ink is recommended for ease of use and durability. Pull the ink firmly toward you with the squeegee. Lift the screen frame to check your print. Multiple prints may be made. For multicolor prints, each color must dry three to five hours before the next color may be printed. Clean the ink out of the frame with water.
Try printing an image in one color of ink for your first project, as multicolor printing can be hard to register on Plexiglas. Solvent-based screen printing inks are available for printing on Plexiglas. These inks offer advantages in full-time professional use, such as quicker drying times.
The screen may stick to the Plexiglas after printing, causing the ink to pucker up as the screen frame is pulled away. Try thinning the ink with either water or ink extender if this happens. Jacquard professional screen printing ink takes up to four days to completely set to maximum durability.